Tag Archives: Paleo Diet

At The Paleo Diet, we look forward to August when our local farmer’s markets are stocked with a plentiful array of fresh-picked produce. We love visiting the various vendors to pick up a bounty of heirloom tomatoes, squash, onions, peppers, lettuce, spinach, peaches, strawberries, melons, and just about anything that grows in our neck of the woods. Right through October, there is little need to visit our local grocery chain, as you can’t beat the freshness of our locally sourced foods. Wherever you reside, give your local growers your support and stock up on some delicious Paleo Diet foods. Give this versatile seasonal favorite from The Paleo Diet kitchen a try. Serve with your favorite fresh greens and some sliced seasonal fruit for an easy, nutritionpacked meal! For more delicious recipes, visit us at: www.thepaleodiet.com

 

Ingredients

  • 1 large 2-3 in diameter squash of your choice, or 4 large peppers
  • 1-pound of ground grass fed beef
  • 3 tablespoons of olive oil
  • ½ yellow onion, chopped
  • 1 cloves garlic, minced
  • ½ large bell pepper, seeds removed and chopped
  • 1 tablespoon of each: fresh thyme, basil, parsley, rosemary and cilantro, finely minced
  • ½ cup water

 

Preheat the oven to 400 degrees. Slice the squash in half lengthwise and scrape out seeds, leaving a 1-2 inch channel to fill later with the beef mixture. Set aside. Brown beef in fry pan on low heat, stirring to be sure the meat is cooked evenly. Heat 1 tablespoon olive oil in a separate medium sized sauté pan, setting aside the rest. Add onion and garlic and sauté on medium heat about 3 minutes. Add the chopped pepper and continue to sauté for an additional 3-5 minutes. Season evenly with fresh herbs and mix throughout the veggies. Add cooked veggies to meat mixture and mix thoroughly. Evenly coat the inside floor of a 1 or 2-inch baking dish with the remaining olive oil. Stuff squash or peppers with the meat mixture and place in baking dish. Add ½ cup water to bottom of dish and cover with foil. Cook for 20 minutes, or until the squash or peppers are tender. Serves up to 4 people.

For more Paleo Diet recipes, visit our website today!

The increased abdominal fat that many women develop after menopause due to hormonal changes and the skin disorder psoriasis are divergent health concerns that would seem to have little in common. But two recently published studies found a common ground – chronic inflammation.

More importantly, the anti-inflammatory properties of the Paleo Diet were found to improve both [1, 2].

After menopause, women have a tendency to “redistribute” fat around the abdomen which increases the risk for metabolic disorders such as diabetes and cardiovascular disease [3, 4]. In the first study, which was published in Obesity, researchers placed 70 obese postmenopausal women on either a Paleo Diet or a “prudent control diet” (CD) for 24 months. The CD diet, also called the Diabetes diet, is recommended for people with diabetes or insulin resistance; it includes higher vegetable, fiber, whole-grain, and fruit consumption along with lower fat intake [5].

Women on both diets were able to reduce adipose tissue and improve their inflammatory markers. However, improvements in the Paleo Diet group were greater. Women in this group were also the only ones to lower two key inflammatory markers – MCP-1 and plasma C-reactive protein (figure 3). This led the researchers to suggest that the Paleo Diet produced “a more pronounced overall decrease in low-grade inflammation compared to the CD group.”

It’s worth pointing out that subjects on the Diabetes diet reported greater difficulty adhering to the diet and had a higher dropout rate [2]. The Diabetes diet differed from the Paleo Diet in only two major ways – unlike the Paleo Diet, it recommended whole grain consumption and it recommended reduced fat intake. The researchers pointed to the fatty acid profile of the Paleo diet as a potential reason for the better inflammatory profile.

The second study, out of the Department of Dermatology at the University of California, took a different tact. The researchers surveyed 1206 psoriasis patients through the National Psoriasis Foundation to determine specific foods and diets that may influence their condition [1].

Tables 4 and 5 below shows reported trigger foods, foods that may have improved symptoms, and diets that patients said helped their condition:

What is fascinating is that with only a few exceptions, the foods that worsened or helped the condition aligned very closely with Paleo Diet recommendations. Likewise, 69 percent of respondents who tried the Paleo Diet found it helped their condition. Many of the other diets on the list, including the Pangano diet (increased fruit and vegetables/decreased nightshades and junk food) have Paleo-like characteristics. In fact, the study reported that compared to controls in the large-scale NHANES 2009-2010 dataset, “respondents reported less daily intake of sugar, whole grain fiber, dairy products, and calcium.” A quote that could be used to describe someone starting a Paleo Diet.

A theme of the two studies was that chronic inflammation was considered both a cause and a major risk factor for co-morbidities. In fact, psoriasis is being increasingly recognized as a systemic inflammatory condition that is associated with a variety of cardiac and metabolic diseases [6-8].

Researchers of the psoriasis study proposed that a poor diet may change the microbiome and digestion leading to poor immune function. They specifically pointed to the consumption of simple carbohydrates (sugar) and nightshades.

Likewise, authors of the postmenopausal study discussed past research showing that fat deposits can increase inflammation and contribute to metabolic dysfunction.  But weight-loss alone did not resolve the inflammation in some of this past research [2, 9]. The authors pointed to the better fatty acid profile of the Paleo Diet – focused on monounsaturated and polyunsaturated fatty acids over saturated fats – as a potential explanation for the better inflammatory profile after both six and 24 months [2].

Perhaps most telling is that after including many diets in their survey, the authors of the psoriasis study specifically called out the Paleo Diet. They wrote the diet “can reduce the risk of cardiometabolic comorbidities in psoriasis which are a predominant cause of reduced life expectancy and an important aspect of disease management” [1].

 

References

  1. Afifi, L., et al., Dietary Behaviors in Psoriasis: Patient-Reported Outcomes from a U.S. National Survey. Dermatol Ther (Heidelb), 2017. 7(2): p. 227-242.
  2. Blomquist, C., et al., Attenuated Low-Grade Inflammation Following Long-Term Dietary Intervention in Postmenopausal Women with Obesity. Obesity (Silver Spring), 2017. 25(5): p. 892-900.
  3. Gaspard, U., Hyperinsulinaemia, a key factor of the metabolic syndrome in postmenopausal women. Maturitas, 2009. 62(4): p. 362-5.
  4. Kranendonk, M.E., et al., Inflammatory characteristics of distinct abdominal adipose tissue depots relate differently to metabolic risk factors for cardiovascular disease: distinct fat depots and vascular risk factors. Atherosclerosis, 2015. 239(2): p. 419-27.
  5. Jonsson, T., et al., Beneficial effects of a Paleolithic diet on cardiovascular risk factors in type 2 diabetes: a randomized cross-over pilot study. Cardiovasc Diabetol, 2009. 8: p. 35.
  6. Takeshita, J., et al., Psoriasis and comorbid diseases: Implications for management. J Am Acad Dermatol, 2017. 76(3): p. 393-403.
  7. Coimbra, S., et al., Systemic inflammation and proinflammatory interleukin-17 signalling persist at the end of therapy in patients with metabolic syndrome and psoriasis, reducing the length of remission. Br J Dermatol, 2016. 174(2): p. 414-6.
  8. Reich, K., The concept of psoriasis as a systemic inflammation: implications for disease management. J Eur Acad Dermatol Venereol, 2012. 26 Suppl 2: p. 3-11.
  9. Magkos, F., et al., Effects of Moderate and Subsequent Progressive Weight Loss on Metabolic Function and Adipose Tissue Biology in Humans with Obesity. Cell Metab, 2016. 23(4): p. 591-601.

 

As a fellow Cornellian, I’ve had a long-standing admiration for Bill Nye The Science Guy. Alright, I admit that I was a fan-boy. I was pretty excited when Nye returned to Cornell during my time there, to take a guest professor post. Here was a scientist who was charismatic, made science exciting for the masses, and had the “science chops” to teach at the Cornell science department.

So, I was all too disappointed when I watched Bill Nye take on the Paleo Diet in his new Netflix show Bill Nye Saves the World. Don’t get me wrong; I wasn’t disappointed because he criticized the diet. As scientists, we welcome criticism and counter-arguments – it makes the science stronger. No, I was disappointed because this scientist, who I admired, not only presented a poor argument, but demonstrated a fundamental misunderstanding of basic science.


An unedited version of the Bill Nye’s Paleo Diet bit isn’t available outside of Netflix. But here’s two YouTube videos showing parts of it – one for and one against:

Bill Nye Disses Paleo. Says Vegan Is The Future
Bill Nye LIES About The Paleo Diet


I do understand that his show is directed at a young audience, so I can forgive a lot. I can even forgive Nye for dressing an actor in bad animal firs, a club, and steel rimmed glasses (apparently a long-forgotten Paleolithic invention made soon after the discovery of fire) and claiming he’s a paleolithic ancestor.

However, when the caveman asks Nye sarcastically “look at me, do I look happy, is this what you want to be?” my only thought was “no, you look like a grown man being paid to act in a bad skit. I wouldn’t be happy either.”

The fact is our unhappy Paleolithic actor doesn’t look anything like a real hunter-gatherer. Just look at him next to this old photo of authentic hunter-gatherers:

 

Do they look happy and healthy? They aren’t smiling. But, they certainly look healthier and fitter than their average modern counterpart. Head-to-head, I would definitely put my money on one of them over Nye’s cavemen – with or without the club.

But again, let’s forgive the costume.

Let’s instead focus on the message. Nye’s caveman continued his rant pointing to himself and saying, “this is not healthy, I’m seventeen.” The underlying message of his rant is that he is representative of the health and happiness of millennia of hunter-gatherer civilizations.

And that’s where Nye crosses a line. Putting a 40-year-old man in a dollar Halloween store caveman get-up is funny. Using that joke as evidence to completely misrepresent entire civilizations seems a little classless.

So, I can forgive the costume, but I can’t forgive the implications. Nye and his caveman make flippant and bold claims about hunter-gatherer health, happiness, and aging without evidence, and in direct contradiction of the established science. Simplifying the science to make it entertaining isn’t an excuse for getting it wrong; especially for someone who’s talent is to make science digestible to the masses.

So, let’s look at what the science really says about his claims. And let’s do it in mostly simple terms to show that the true science is digestible. Nye and his caveman make four arguments against The Paleo Diet. First that the diet is all protein which is dangerous. Second, that Nye’s caveman is 17-years-old and “not healthy,” implying that hunter-gatherers aged very rapidly and poorly. Third, that their diet didn’t help with disease because our paleolithic ancestors did not live long enough to suffer from now common conditions like cancer and heart attacks. And finally, that the caveman is clearly unhappy living a Paleo life.

I could address that final argument with dozens of accounts of how tribal cultures centered around their regular feast and the joy experienced at these community events. But you know what, that would be a lot of energy focused on addressing a bad joke. Forget the science – I’m just going to recommend Nye takes a couple hours to watch Dances with Wolves.

 

Bill Nye Gets Hunter-Gatherer Aging and Health Wrong

Let’s address the second and third arguments – first that hunter-gatherers aged rapidly and poorly and second, that they didn’t live long enough to develop cancer and other degenerative diseases. These are common misconceptions easily disproved by current science.

Yes, the average life-expectancy of ancient hunter-gatherer societies was somewhere between 20-years of age and late 30s [1-6]. But that does not mean, as Nye implies, that 30-year-olds looked like frail modern-day 80-year-olds.

Life expectancy and aging are two very different things.  Life expectancy is determined using a complex multi-factorial equation that considers all causes of death including illness, accidents and war, It also factors in mortality rates of children, full-grown adults and the elderly, Delve deeper and you have to understand things like senescence, life tables and mortality hazard rates [6].

That’s a mouthful, and not something that Nye’s audience should have to understand – but Nye should.

Put simply, life expectancy says very little if anything about the aging process. If life expectancy was 30, that does not mean that people died of old age at 30. War, disease, and high childhood mortality all affect the number. In fact, the biggest factor in life expectancy is childhood mortality. Life expectancy in hunter-gatherer societies were so much lower than modern day societies because of the rates of childhood mortality were very high, as this graph of Hiwi hunter-gatherers shows [2]:

In 2007, Michael Gurven, PhD and Hillard Kaplan, PhD published the most extensive study of hunter-gatherer life expectancy and longevity to date. And they used actual records of deaths from multiple recent hunter-gatherer societies instead of calculations and theory like previous studies.

Showing just how big a factor childhood mortality was, they compared mortality rates of their hunter-gatherer societies to modern Americans [6]:

What this graph shows, simply, is that mortality rates in childhood are up to 100 times higher in hunter-gatherers than modern humans. But for those who lived past the age of 15, their life-expectancy was very similar to modern humans.

Gurven and Kaplan concluded their study by stating:

Our results contradict Vallois’s claim that among early humans, “few individuals passed forty years, and it is only quite exceptional that any passed fifty”… The data shows that modal adult life span is 68-78 years and that it was not uncommon for individuals to reach these ages, suggesting that inferences based on paleodemographic reconstruction are unreliable.

In other words, claims that life was short was based on unreliable data. Hunter-gatherers who survived to the age of 15 in fact aged no faster than modern humans and frequently lived into their 70s.

A better way to estimate the age at which people tended to die of old age is modal age. Sorry again for the complex term. Simply put, it’s the most common age of death. Gurven and Kaplan determined the modal ages for modern Americans and for both recent and ancient hunter-gatherers:

While modern Americans have the highest model age of death, the differences are not that great. The modal adult life span ranged from 68-78 years for pre-modern societies [6].

Nye’s failure to understand this accepted science about aging and life span led to his other mistaken argument. He claimed that while our Paleolithic ancestors had few chronic diseases, it was because no one lived long enough to contract them and not because of lifestyle or diet.

Gurven and Kaplan explored causes of death as well. They divided the causes into four categories: illness (such as respiratory infection and gastrointestinal problems,) accidents, violence, and degenerative deaths (cancer, heart disease, old-age.) Gurven and Kaplan, admitted that chronic illness was hard to diagnose in these societies. However, since the other three causes accounted for, on average, 90.8% of deaths, degenerative death was at most a minor factor at 9.2% [6]. Even in those who survived to old age, degeneration still only accounted for 28.2% of deaths in adults over 60 years of age.

Contrast those rates to the 2015 Center For Disease Control statistics on the top 10 causes of death in America where the seven leading degenerative conditions (heart disease, cancer, stroke, Alzheimer’s disease, diabetes, and nephritis) accounted for 59.4% of deaths [7]:

It’s important to recognize that this higher percentage in modern Americans is due in part or mostly to a drop in deaths due to illness, injury and violence and not just a rise in chronic disease.

However, contradicting Nye’s claim that chronic illness is purely an old-age phenomena, among adults aged 25-44, the four top degenerative conditions alone (including cancer) accounted for 30% of deaths in America in 2015 [7]. Death rates were similar between hunter-gatherers and modern Americans in this age range [6] yet for hunter-gatherers, all degenerative diseases accounted for only 9.2% of deaths in adults aged 15 to 59 [6].

The fact is, if the appearance of chronic disease was purely due to people living longer, then we wouldn’t have had a dramatic rise in these conditions in recent decades including a rise in childhood cancer, diabetes, and other chronic conditions. [4, 5, 8-12]. Chronic disease among US children increased from 12.8% in 1994 to 26.6% in 2006 alone [12]. A rise that corresponds more with dietary changes like the increase in high-carbohydrate diets and refined sugars.

Gurven and Kaplan wrote that “degenerative deaths are relatively few, confined largely to problems early in infancy and late-age cerebrovascular problems, as well as attribution of ‘old-age’ in the absence of obvious symptoms… heart attack and stroke appear rare and do not account for these old-age deaths.”

The general good health was also reflected in Captain Cook’s account of the native Maori during his 1772 expedition to New Zealand:

A further proof that human nature here is untainted with disease is the great number of old men that we saw… appeared to be very ancient, yet none of them were decrepit; and though not equal to the young in muscular strength, were not a whit behind them in cheerfulness and vivacity.

Simply put, hunter-gatherers lived a much longer, healthier and happier life than Bill Nye claimed. We have a wealth of ethnographic science to show this. He has an actor with a club.

 

Bill Nye Gets the Paleo Diet Wrong… and Nutrition in General

Nye very correctly states that an all-protein diet is dangerous. Dr Loren Cordain even wrote in the original Paleo Diet book that consuming more than about 35% of our calories from protein can lead to a fatal condition called rabbit starvation [4].

However, the fact that Nye believes the Paleo Diet is an all-protein diet demonstrates that he didn’t bother to research the diet before attacking it. He also makes some very basic nutrition mistakes. Even if hunter-gatherers ate only meat (which they didn’t), meat is not all-protein. It’s often not even predominantly protein. It contains fat– a macronutrient that Nye failed to even mention. Yet, the types of fat we eat have a profound impact on our health.

Hunter-gatherer diets in fact ranged from 19-35% protein and 22-40% carbohydrate [13]. Further, about 35-45% of hunter-gatherer’s total calories came from fruits and vegetables. And since meat is far more calorie dense, hunter-gatherers ate a greater volume of carbohydrate-rich plant food than meat [14].

Nye continued to demonstrate a lack of understanding of basic nutrition by saying that “eating Paleo means giving up pasta, breads: carbohydrates.”

Again, this is basic nutrition. Grains are not our only carbohydrate source. Vegetables and fruits are considered carbohydrate sources as well. They are also more nutrient dense than grain products, and even Paleo-detractors will generally agree that fresh vegetables are healthier than bread and pasta [4, 5, 13, 15, 16].

So yes, an all-protein, all-meat diet is bad for you. But what does that have to do with The Paleo Diet or basic nutrition in general? I challenge Nye to eat an all-protein diet. I’m not sure it’s physiologically possible.

 

Bill Nye Is Trying to Save the World

Nye has publicly stated his support for a vegan diet. And don’t get me wrong; I admire vegans – when they are doing it for ethical or sustainability reasons. Sustainability is a legitimate concern and Dr. Cordain has published a paper stating that the world’s population has exceeded what can be supported on a Paleo Diet [17].

My co-thesis advisor researched beans and rice. She claimed a few times that “Trevor is working with Dr. Cordain to help figure out what’s the healthiest diet. I’m trying to figure out how to feed the world.”

But, supporting a vegan diet for sustainability reasons doesn’t also automatically make it healthier. Nor does it make the diet our bodies evolved around less healthy. It’s noble for a scientist to want to “save the world” and maybe a little cocky to name your show that. But no scientist will save anything by getting the basic science wrong.

 

References

1. Karasik, D., B. Arensburg, and O.M. Pavlovsky, Age assessment of Natufian remains from the land of Israel. American Journal of Physical Anthropology, 2000. 113(2): p. 263-274.
2. Hill, K., A.M. Hurtado, and R.S. Walker, High adult mortality among Hiwi hunter-gatherers: Implications for human evolution. Journal of Human Evolution, 2007. 52(4): p. 443-454.
3. Trinkaus, E., Late Pleistocene adult mortality patterns and modern human establishment. Proceedings of the National Academy of Sciences of the United States of America, 2011. 108(4): p. 1267-1271.
4. Cordain, L., The Paleo diet : lose weight and get healthy by eating the foods you were designed to eat. Rev. ed. 2011, Hoboken, N.J.: Wiley. xv, 266 p.
5. Eaton, S.B., M. Konner, and M. Shostak, Stone agers in the fast lane: chronic degenerative diseases in evolutionary perspective. Am J Med, 1988. 84(4): p. 739-49.
6. Gurven, M. and H. Kaplan, Longevity among hunter-gatherers: A cross-cultural examination. Population and Development Review, 2007. 33(2): p. 321-365.
7. Statistics, N.C.f.H., Health, United States, 2016: With Chartbook on Long-term Trends in Health, U.D.o.H.a.H. Services, Editor. 2017. p. 488.
8. Anderson, G. and J. Horvath, The growing burden of chronic disease in America. Public Health Rep, 2004. 119(3): p. 263-70.
9. Gale, E.A., The rise of childhood type 1 diabetes in the 20th century. Diabetes, 2002. 51(12): p. 3353-61.
10. Eaton, S.B., L. Cordain, and P.B. Sparling, Evolution, body composition, insulin receptor competition, and insulin resistance. Prev Med, 2009. 49(4): p. 283-5.
11. Eaton, S.B. and M. Konner, Paleolithic nutrition. A consideration of its nature and current implications. N Engl J Med, 1985. 312(5): p. 283-9.
12. Van Cleave, J., S.L. Gortmaker, and J.M. Perrin, Dynamics of Obesity and Chronic Health Conditions Among Children and Youth. Jama-Journal of the American Medical Association, 2010. 303(7): p. 623-630.
13. Cordain, L., et al., Origins and evolution of the Western diet: health implications for the 21st century. Am J Clin Nutr, 2005. 81(2): p. 341-54.
14. Cordain, L., et al., Plant-animal subsistence ratios and macronutrient energy estimations in worldwide hunter-gatherer diets. Am J Clin Nutr, 2000. 71(3): p. 682-92.
15. Cordain, L., et al., Macronutrient estimations in hunter-gatherer diets. Am J Clin Nutr, 2000. 72(6): p. 1589-92.
16. Eaton, S.B. and S.B. Eaton, 3rd, Paleolithic vs. modern diets–selected pathophysiological implications. Eur J Nutr, 2000. 39(2): p. 67-70.
17. Cordain, L., Cereal grains: humanity’s double-edged sword. World Rev Nutr Diet, 1999. 84: p. 19-73.

US Government Poised to Drop Cholesterol Warnings? | The Paleo DietCholesterol – is there a more controversial topic in the world of nutrition? For years, we were told that cholesterol is one of the most important biomarkers of health, particularly cardiovascular health. Prominent government- and health-related institutions have traditionally recommended upper limits on dietary cholesterol of 300 mg/day (effectively limiting egg consumption to 1 egg per day.) A recommendation based on the theory that dietary cholesterol – the cholesterol contained in food – negatively impacts cholesterol found in the blood, called serum cholesterol.

With the emergence of more and more scientific evidence, however, this theory has become increasingly untenable, causing many scientists to change their views on cholesterol. The counter theory – that dietary cholesterol has little impact on serum cholesterol – is actually nothing new. Even the progenitor of the misguided lipid theory of heart disease, Ancel Keys, acknowledged back in 1953 that dietary cholesterol doesn’t significantly impact serum cholesterol.1

Unfortunately, cholesterol came to be demonized due to its association with saturated fat and for decades both were thought to be unhealthy. New studies in the past several years have challenged this orthodox view of cholesterol.

The new research has also challenged traditional beliefs about eggs. Rather than limiting egg consumption, the available evidence suggests that eggs are actually cardio-protective.

In March 2017, for example, The Journal of Nutrition published a new study about egg consumption and its positive effects on both HDL function and plasma antioxidant levels.2 Previous studies had shown similar benefits, but those studies were largely conducted on unhealthy populations.3,4,5

The authors of this new study, therefore, decided to test how eating one, two, or three eggs daily would affect healthy young adults. This study was the latest in a series of scientific papers showing that foods rich in dietary cholesterol can actually decrease one’s risk for heart disease – a complete turnaround from the institutional forebodings of decades past.

 

Important, But Not Essential

Cholesterol is not an essential nutrient. This means that although your body requires cholesterol, you’re not dependent on food to obtain it. In fact, your liver produces 90% of the cholesterol needed by your body. Some people use this fact to advance the hypothesis that dietary cholesterol is unnecessary or even unhealthy. This hypothesis is flawed for several reasons, including:

  1. The foods that contain significant amounts of cholesterol also contain many other important nutrients, particularly iron, and vitamin B12.
  2. Nearly all foods that contain bioavailable forms of high-quality protein also contain cholesterol.

 

The Origins of the Theory

So where does the idea that dietary cholesterol is unhealthy come from? Surprisingly, the early studies that inspired this idea were actually conducted on rabbits. While this may seem reasonable, it’s important to remember that rabbits are herbivores. And since their natural diets don’t contain cholesterol, it’s no surprise that it impacts them negatively.

Nikolay Anichkov was the scientist who originally conducted these rabbit studies back in the early 20th century. Interestingly, he fed rabbits a purified form of cholesterol.6 Obtaining cholesterol this way is completely different from obtaining cholesterol from healthy foods. In fact, most of Anichkov’s peers questioned the relevance to human health of his cholesterol experiments performed on rabbits.

Nearly 40 years later, John Gofman became the next major researcher to show interest in the topic. Gofman reported that higher levels of LDL were associated with an increased risk for coronary heart disease (CHD), whereas higher levels of HDL appeared to protect against CHD.7

After Gofman, Ancel Keys became the most prominent heart disease researcher. Through a series of experiments, Keys concluded that saturated fat consumption has the biggest impact on serum cholesterol levels. However, regarding dietary cholesterol, as mentioned above, Keys reported, “repeated careful dietary surveys on large numbers of persons in whom blood cholesterol was measured consistently fail to disclose a relationship between the cholesterol in the diet and in the serum.”8

Keys became known as the father of the lipid hypothesis – the theory that fat consumption, particularly saturated fat, drives heart disease. During the past 15 years or so, the lipid hypothesis has faced serious challenges. One of its core tenets is that saturated fat increase LDL cholesterol, which does in fact correlate with heart disease. However, LDL varies by particle size – small or large.

 

Small versus Large

Small particle LDL is more prone to oxidation and to the formation of subsequent arterial lesions and arterial plaque.9 Large particle LDL is less susceptible to such modifications and therefore carries little, if any, cardiovascular risk. In fact, a study that tracked women for 11 years found no significant association between large particle LDL and cardiovascular disease risk (CVD).10

So how does all this relate to eggs and their relatively high amounts of dietary cholesterol? Some interesting findings emerged from the recent Journal of Nutrition study.2 For example, as egg consumption increased, small LDL decreased and large LDL increased – a win-win with respect to reducing CVD risk. Additionally, concentrations of HDL and the antioxidants lutein and zeaxanthin also increased as daily egg consumption went up.2

One great benefit of HDL is its ability to remove cholesterol from macrophages. This is one of the key aspects of preventing the build-up of cholesterol inside the blood vessels. Additionally, this is one reason why low HDL is related to increased CVD risk.11

 

Conclusions

Eggs have gotten a bad rap, mostly due their high levels of cholesterol and due to our imprecise, yet ever-evolving, views on the relationship between cholesterol-rich foods and blood cholesterol levels.

Unfortunately, the nutrition establishment is still struggling to acknowledge the obvious – that eggs and other cholesterol-rich foods are healthy. Back in 2015, the USDA was in the process of updating its official Dietary Guidelines for Americans. In its Preliminary Report, published in February 2015, the group’s Advisory Committee recommended dropping the decades old 300 mg/day limit on dietary cholesterol. The available evidence, they reported, “shows no appreciable relationship between consumption of dietary cholesterol and serum cholesterol.”12 Accordingly the committee concluded, “cholesterol is not a nutrient of concern for over-consumption.”

Unfortunately, as soon as the clouds of bad conclusions dissipated, they quickly reemerged, again blocking the light of reason and evidence. For in their final report, published in January 2016, the USDA backed away from the Preliminary Report’s encouraging conclusions. Instead, they settled on “individuals should eat as little dietary cholesterol as possible while consuming a healthy eating pattern.”13

So we’re back to square one. The usual suspects are still warning against dietary cholesterol, whereas the scientific evidence draws other conclusions. Egg-white omelets are still served in many restaurants, whereas the nutrient-rich yolks are often discarded. Are eggs healthy? The science says yes, but you can decide.

References

[1] Keys, A. (1953). Prediction and Possible Prevention of Coronary Disease. Am J Public Health Nations Health., 43(11). Retrieved from (link).

[2] DiMarco DM, et al. (2017). Intake of up to 3 Eggs per Day Is Associated with Changes in HDL Function and Increased Plasma Antioxidants in Healthy, Young Adults. Journal of Nutrition, 147(3). Retrieved from (link).

[3] Herron KL, et al. (2004). High intake of cholesterol results in less atherogenic low-density lipoprotein particles in men and women independent of response classification. Metabolism, 53(6). Retrieved from (link).

[4] Mutungi G, et al. (2008). Dietary Cholesterol from Eggs Increases Plasma HDL Cholesterol in Overweight Men Consuming a Carbohydrate-Restricted Diet. Journal of Nutrition, 138(2). Retrieved from (link).

[5] Blesso CN, et al. (2013). Whole egg consumption improves lipoprotein profiles and insulin sensitivity to a greater extent than yolk-free egg substitute in individuals with metabolic syndrome. Metabolism, 62(3). Retrieved from (link).

[6] Finking G, et al. (1997). Nikolaj Nikolajewitsch Anitschkow (1885-1964) established the cholesterol-fed rabbit as a model for atherosclerosis research. Atherosclerosis, 135(1). Retrieved from (link).

[7] Gotto AM, et al. (2011). Jeremiah Metzger Lecture: Cholesterol, Inflammation and Atherosclerotic Cardiovascular Disease: Is It All LDL? Trans Am Clin Climatol Assoc., 122. Retrieved from (link).

[8] Keys, A. (1953). Prediction and Possible Prevention of Coronary Disease. Am J Public Health Nations Health., 43(11). Retrieved from (link).

[9] Ross R. (1999). Atherosclerosis – an inflammatory disease. New England Journal of Medicine, 340(2). Retrieved from (link).

[10] Mora S, et al. (Feb 2009). Lipoprotein particle profiles by nuclear magnetic resonance compared with standard lipids and apolipoproteins in predicting incident cardiovascular disease in women. Circulation, 119(7). Retrieved from (link).

[11] Assmann G, et al. (1996). High-density lipoprotein cholesterol as a predictor of coronary heart disease risk. The PROCAM experience and pathophysiological implications for reverse cholesterol transport. Atherosclerosis, 124. Retrieved from (link).

[12] 2015 Dietary Guidelines Advisory Committee. (Feb 2015). Scientific Report of the 2015 Dietary Guidelines Advisory Committee. US Department of Health and Human Services and US Department of Agriculture. Retrieved from (link).

[13] USDA. (2016). Dietary Guidelines for Americans, Final Report. Retrieved from (link).

2016 Fireworks | The Paleo Diet

Paleo critics are always voicing unsubstantiated claims. Their attacks are easily countered, but they sometimes create confusion and discouragement, especially for those who are new to Paleo. The British Dietetic Association, for example, has called Paleo a “time consuming, socially-isolating diet.” If you’re just starting out with Paleo, it’s probably better to get your advice from people who actually follow the lifestyle, not from critics who simply parrot talking points.

The Paleo Diet shouldn’t be time consuming or socially isolating, nor should it be overly expensive. Above all, the Paleo Diet is flexible. Whatever your personal circumstances, you can customize the Paleo Diet so it works for you. Here are 5 great tips to get you started.

1. Master the Slow-Cooker

The slow-cooker is one of your best kitchen-friends. It saves you time and money while helping you cook meals that taste like they were prepared by a professional chef…or by your grandmother. With a slow-cooker, you can save money on meat by buying the cheaper, tougher cuts, which are just as tasty (and nutritious) after being cooked for several hours.

The slow-cooker also saves you time, because the cooking is passive. Slow-cookers are designed to be safe even when they are unattended. Most of us would be wary about leaving the oven or stove turned on while we were away from the house for several hours. With a slow-cooker, however, this is perfectly acceptable.

2. Eating at Restaurants

Paleo need not be “socially isolating.” Sure, if your friends are going out for pizza and sodas, you should probably pass, but at most restaurants you’ll find plenty of Paleo-compliant choices. Go for grilled meat or fish plus steamed vegetables or a salad. Salad dressings will typically have canola or other vegetable oils, so ask your server to bring you olive oil and lemon juice on the side.

3. Lunch On the Go

The reality of our modern lifestyles is that you probably won’t be able to eat every meal at home. Get into the habit of taking your lunch with you, especially if you work at an office. Make a Paleo meal, preferably something that tastes good cold, and get some glass or BPA-free plastic storage containers with lids that lock into place. Usually you can find mini-size containers for sauces and dressing, so as to avoid soggy salads.

4. Strategic Leftovers

Another key to minimizing kitchen time is using leftovers strategically. This starts by intentionally cooking extras, with the plan of using these extras for upcoming meals. For example, you’re cooking steaks. Cook one or two more than you need. Let them cool and then refrigerate. Later, slice thinly with a sharp knife. Add this to a salad. Congratulations, you’re salad has just become a complete meal. You can do the same thing with turkey, duck, lamb, and other meats.

5. Making Fabulous Sauces

A great way to fancy up your vegetable dishes is with sauces. Sure, you could just drizzle some coconut oil or olive oil on salads and steamed vegetables, but sauces bring these foods to another level, which might be important for you, especially if you are seeking more variety and when cooking for family or friends.

Here’s a simple sauce strategy. You’ll need a blender, preferably a small one. Blend a small handful of nuts (cashews, almonds, or macadamia) with a couple spoons of olive oil, a few spoons of lemon juice, and a handful of washed herbs (stems removed), like parsley, cilantro, or mint. Add just enough water to achieve a smooth, creamy texture.

You’ll find plenty more tips and tricks throughout this website. Start the New Year off right. Make Paleo work for you!

Maca Root Powder | The Paleo Diet
Dear Dr. Cordain,

Thank you for your great YouTube vidoes and your website. I found them last week after some detours through a few pale imitators, and have begun transitioning to the Paleo diet according to your interpretation, which I consider to be the most authentic. In only about a week, I am feeling much less bloated, have fewer cravings, and think my body looks slightly different. I love how deeply the foundations of the diet have been researched and how well you explain it.

I have a question about maca root, which I have just learned is from a plant in the brassica family. I have a thyroid condition which manifests as hypothyroid (Grave’s Disease, 38 years post-thyroidectomy of 90% of the organ), so avoid cruciferous vegetables pretty regularly. I have been taking synthroid for about 15 years. I’m 59 years old, and have used maca for a few years as a post-menopausal adaptogen. Now, that I know that maca is in the brassica family, I have a concern about whether or not it might be best to eliminate it from my diet. I am using a raw, organic, powdered version at about 1-2 teaspoons a day.

I know you can’t give me medical advice. My question is whether or not you know if maca shares all the same anti-nutritional properties of other brassicas. If I know that and will share it with me, I can make an educated choice whether or not to continue ingesting it.

Many thanks!

Margaret

Dr. Cordain’s Response

Hi Margaret,

Many thanks for your kind words about my research on the Paleo diet. Let me answer your question about maca root (Lepidium meyenii) which is indeed a member of the brassica family.

In theory powdered maca root could adversely affect throid function because of the presence of glucosinolates.1 In my blog post “Millet: A Gluten-Free Grain You Should Avoid” I have explained how concentrated sources of these compounds may adversely affect thyroid function and cause goiter.

Generally, in people with normal thyroid function consumption of brassica plants have no adverse effects. Only when thyroid is impaired by pre-existing low plasma iodine levels does consumption of brassica exacerbate the problem. A study in rats demonstrated no change in thyroid function via measurement of thyroid stimulating hormone (TSH) following both short and long term consumption of Lepidium species.2 Hence, unless a person has a pre-existing thyroid problem or low blood concentrations of iodine, consumption of maca root powder generally appears to be safe.

References

1. Valerio LG, Gonzales GF. Toxicological aspects of the South American herbs cat’s claw (Uncaria tomentosa) and maca (Lepidium meyenni)

2. H. O. Meissner, B. Kedzia, P. M. Mrozikiewicz, and A. Mscisz. Short and Long-Term Physiological Responses of Male and Female Rats to Two Dietary Levels of Pre-Gelatinized Maca (Lepidium Peruvianum Chacon) Int J Biomed Sci. 2006 Feb; 2(1): 13–28.

Beans and Legumes | The Paleo Diet

A few days ago I was delighted to learn that Dr. Oz was going to again feature The Paleo Diet on his nationally syndicated television show along with one of my co-authors, Nell Stephenson, of The Paleo Diet Cookbook. I tuned into the Dr. Oz show and was happy about most of what I saw except for Chris Kresser, expounding upon the health virtues of a food group, beans and legumes, that definitely are not Paleo. Please read the following article on beans and legumes, and decide for yourself if beans and legumes are Paleo and feel free to pass this information on to your friends, family and anyone interested in starting a Paleo Diet.

In the decade since I wrote The Paleo Diet, a question that comes up time and again is, “Why can’t I eat beans?”  I briefly touched upon this topic in my first book, but never really was able to get into the necessary detail of why you should avoid not only beans, but all other legumes including peanuts and soy.  Now let me bring you fully up to date on recent developments about our understanding of how beans, soy and other legumes may impact our health.  But most importantly, I’ll show you beyond a shadow of a doubt why legumes are inferior foods that should not be part of any contemporary Paleo Diet.

Toxicity of Uncooked Beans

It may come as a surprise to you, but as recently as 19 years ago imports of red kidney beans into South Africa were legally prohibited because of “their potential toxicity to humans” (63).  Although many people think about kidney beans as nutritious, plant based high-protein foods; few would ever consider them to be toxic poisons.  But indeed toxic they are – unless adequately soaked and boiled kidney beans and almost all legumes produce detrimental effects in our bodies.  Starting in the early 1970’s a number of scientific papers reported that consumption of raw or undercooked red kidney beans caused nausea, vomiting, abdominal pain, severe diarrhea, muscle weakness and even inflammation of the heart (42, 52, 60).  Similar symptoms were documented in horses and cattle (8).  Further, raw kidney beans were lethally toxic to rats when fed at more than 37 % of their daily calories  (24, 27, 51).  Like the proverbial canary in a coal mine, these clues should make us proceed cautiously as we consider the nutritional benefits and/or liabilities of beans and legumes.  Before I get into why raw or partially cooked beans, legumes and soy are toxic, I want to first point out the obvious – these foods (even when fully cooked) are nutritional lightweights when compared to meat, fish and other animal foods.

 The Nutrient Content of Beans and Legumes

If we examine the USDA’s My Plate, governmental nutritionists have arbitrarily created five food groups: 1) grains, 2) vegetables, 3) fruit, 4) dairy and 5) protein foods (61).  On the surface, these categories seem reasonable, and I would basically agree that most common foods could logically be placed into one of these five categories except for one glaring exception – protein foods.

Upon more careful inspection of this category we find the USDA has decided that protein foods should include: 1) meat, 2) poultry, 3) fish, 4) eggs, 5) nuts and seeds and 6) dry beans and peas.  I have little disagreement that meat, poultry, fish and eggs are good sources of protein.  However, digging a little bit deeper, we soon find that the USDA tells us that these six protein food groups are equivalent and can be used interchangeably with one another (61) – meaning that animal protein sources (meats, poultry, fish and eggs) are nutritionally comparable to plant protein sources (nuts, seeds, dry beans and peas).  OK? It gets better still.  I quote the USDA My Plate recommendations:

“Dry beans and peas are the mature forms of legumes such as kidney beans, pinto beans, black-eyed peas, and lentils.  These foods are excellent sources of plant protein, and also provide other nutrients such as iron and zinc.  They are similar to meats, poultry, and fish in their contribution of these nutrients.  Many people consider dry beans and peas as vegetarian alternatives for meat.” (61).

The Paleo Diet

OK let’s let the data speak for itself and really see how “dry beans and peas” stack up to meats, poultry, fish and eggs in terms of protein, iron and zinc as alluded to by the USDA.  In the figure below [data from (66)] you can see that on a calorie by calorie basis, legumes are utter lightweights when compared to the protein content of lean poultry, beef, pork and seafood. Nuts and seeds fare even worse.  Beans, peas and other legumes contain 66 % less protein than either lean chicken or turkey, and 61 % less protein than lean beef, pork and seafood.  What the USDA doesn’t tell us is that our bodies don’t process bean and legume proteins nearly as efficiently as plant proteins – meaning that the proteins found in beans, peas and other legumes have poor digestibility.

The Food and Agricultural Organization (FAO)/World Health Organization (WHO) of the United Nations have devised a protein quality index known as the Protein Digestibility-Corrected Amino Acid Score (PDCAAS).  This index reveals that beans and other legumes maintain second-rate PDCAAS ratings which average about 20 to 25 % lower than animal protein ratings (14).  So to add insult to injury legumes and beans not only contain about three times less protein than animal foods, but what little protein they do have is poorly digested.  Their poor PDCAAS scores stem from a variety of antinutrients which impair protein absorption (20, 29, 44) and from low levels of two essential amino acids (cysteine and methionine) (66).  I don’t know about you, but I have no idea how the USDA concluded that legumes are, “excellent sources of plant protein . . . similar to meats, poultry, and fish in their contribution of these nutrients.

Now let’s take a look at the average zinc and iron content of eight commonly eaten legumes (green peas, lentils, kidney beans, lima beans, garbanzo beans [chick peas], black-eyed peas, mung beans and soybeans).  In the two figures below, I have contrasted the average iron and zinc content [data from (66)] of these eight legumes to lean chicken, turkey, beef, pork and seafood.

The Paleo Diet

The Paleo Diet

Notice that the iron content of legumes appears to be similar to seafood and about twice as high as in lean meats and eggs.  Once again, as was the case with legume protein, this data is misleading because it doesn’t tell us how legume iron is handled in our bodies.  Experimental human studies from Dr. Cook’s laboratory in Switzerland and (30) from Dr. Hallberg’s research group in Sweden (26) have shown that only about 20 to 25 % of the iron in legumes is available for absorption because it is bound to phytate.  So in reality, the high iron content of legumes (2.2 mg/100 kcal) plummets by 75 – 80 %, thereby making legumes a very poor source of iron compared to animal foods.  A similar situation occurs with zinc, as phytate and other antinutrients in legumes severely reduce its absorption in our bodies (13, 19, 57).  Given that this information has been known for more than 30 years, it absolutely defies logic how the USDA could misinform the American public by declaring that, “These foods are excellent sources of plant protein, and also provide other nutrients such as iron and zinc.  They are similar to meats, poultry, and fish in their contribution of these nutrients.” 

Antinutrients in Beans and Legumes

From the picture I have painted so far, you can see how misleading it can be to evaluate the nutritional and health effects of beans and other legumes by simply analyzing their nutrient content on paper, as the USDA has done.  Before we can pass nutritional judgment on any food, it is absolutely essential to determine how it actually acts within our bodies.  Beans are not good sources of either zinc or iron, and they have low protein digestibility because these legumes are chock full of antinutrients that impair our body’s ability to absorb and assimilate potential nutrients found in these foods.

As with whole grains, the primary purpose of most antinutrients in legumes is to discourage predation and prevent destruction of the plant’s reproductive materials (e.g. its seeds) by microorganisms, insects, birds, rodents and large mammals (10, 25).  We most frequently refer to legume seeds as beans, but don’t forget that peanuts are not really nuts at all, but rather are legumes.  In the table below I have listed some of the more commonly known legume seeds along with their scientific names.

Table of Commonly Consumed Legumes

The Paleo Diet

Part of the reason for doing this is to point out that many different versions of the beans we frequently eat actually are the exact same species – and as such contain comparable concentrations of toxic antinutrients.  Notice how many times you see the scientific name, Phaseolus vulgaris, repeated in the table above.  If you enjoy Mexican food then you have probably tasted Phaseolus vulgaris as either refried beans or black beans, since these two beans are one in the same species, differing only by color.  Great northern beans, green beans, kidney beans, navy beans, pinto beans and white kidney beans also are members of the same species, Phaseolus vulgaris.  I bring this information up because all beans that are members of Phaseolus vulgaris contain some of the highest concentrations of antinutrients known.

The list of antinutrients found in legumes, beans and soy is seemingly endless and includes: lectins, saponins, phytate, polyphenols (tannins, isoflavones), protease inhibitors, raffinose oligosaccharides, cyanogenetic glycosides, and favism glycosides.  I know that this list appears somewhat formidable at first because of all the scientific terms, but don’t be worried – the concepts underlying how these toxins may impair our health are easily understood.  Let’s briefly go through this list so you can clearly understand why you should avoid legumes.

Lectins

All beans and legumes are concentrated sources of lectins.    Lectins are potent antinutrients that plants have evolved as toxins to ward off predators (10).  You remember from earlier in this chapter that raw or undercooked kidney beans caused severe cases of food poisoning in humans and were lethally toxic in rats.  Although several kidney bean antinutrients probably contributed to these poisonous effects, animal experiments indicate that a specific lectin found in kidney beans was the major culprit (2, 44).  Kidney beans and all other varieties of beans (black beans, kidney beans, pinto beans, string beans, navy beans etc.) within the Phaseolus vulgaris species contain a lectin called phytohemagglutinin (PHA).  The more PHA we ingest, the more ill we become.  This is why raw beans are so toxic – they contain much higher concentrations of PHA than cooked beans (4, 23. 46).  However, cooking doesn’t completely eliminate PHA, and even small amounts of this lectin are known to produce adverse health effects, providing they can penetrate our gut barrier.

The trick with lectins is that they must bypass our intestinal wall and enter into our bloodstream if they are to wreak havoc within our bodies. So far, no human studies of PHA have ever been conducted.  However, in laboratory animals, PHA easily breeches the gut barrier and enters into the bloodstream where it may travel to many organs and tissues and disrupt normal cell function and cause disease (45, 49).  Human and animal tissue experiments reveal that PHA and other food lectins can cause a “leaky gut” and enter circulation (24, 34, 35, 45, 47, 49, 64, 65) .  A leaky gut represents one of the first steps implicated in many autoimmune diseases (67).  Impaired intestinal integrity produced by dietary lectins may also my cause low level inflammation in our bloodstreams (15, 43, 48, 62) – a necessary step for atherosclerosis (the artery clogging process) and cancer.

Besides  kidney beans and other bean varieties within Phaseolus vulgaris species, all other legumes contain lectins with varying degrees of toxicity ranging from mild to lethal.   Soybean lectin (SBA) is also known to impair intestinal permeability and cause a leaky gut (1, 35).  Peanut lectin (PNA) is the only legume lectin to have been tested in living humans by Dr. Rhodes’ research group in London.  Within less than an hour after ingestion in healthy normal subjects, PNA entered their bloodstreams (64) – whether the peanuts were cooked or not.   Later I will show you how peanuts and PNA are potent initiators of atherosclerosis.

The lectins found in peas (PSA) and lentils (LCA) seem to be much less toxic than PHA, SBA or PNA, however they are not completely without adverse effects in tissue and animal experiments (9, 21, 25, 38 ).  Unfortunately, no long term lectin experiments have ever been conducted in humans.  Nevertheless, from animal and tissue studies, we know that these antinutrients damage the intestinal barrier, impair growth, alter normal immune function and cause inflammation.

Saponins

The term, saponin, is derived from the word soap.  Saponins are antinutrients found in almost all legumes and have soap-like properties that punch holes in the membranes lining the exterior of all cells.  As was the case with lectins, this effect is dose dependent – meaning that the more saponins you ingest, the greater will be the damage to your body’s cells.  Our first line of defense against any antinutrient is our gut barrier.  Human tissue and animal studies confirm that legume saponins can easily disrupt the cells lining our intestines and rapidly make their way into our bloodstream (1, 16, 17, 18, 32 ).  Once in the bloodstream in sufficient quantities, saponins can then cause ruptures in our red blood cells in a process known as hemolysis which can then temporarily impair our blood’s oxygen carrying capacity (3).  In the long term, the major threat to our health from legume saponins stems not from hemolysis (red blood cell damage) but rather from their ability to increase intestinal permeability (3, 16, 17, 18, 32)  A leaky gut likely promotes low level inflammation because it allows toxins and bacteria in our guts to interact with our immune system.  This process is known to be is a necessary first step in autoimmune diseases (67) and may promote the inflammation  necessary for heart disease and and the metabolic syndrome to develop and progress (68).

The other major problem with legume saponins is that cooking does not destroy them.  In fact, even after extended boiling for two hours, 85-100 % of the original saponins in most beans and legumes remain intact (55).   On the other hand, by eating fermented soy products such as tofu and tempeh, or sprouted beans you can lower your saponin intake (39).  The table below shows you the saponin content of some common beans, legumes and soy products.

Saponin Content of Selected Beans, Legumes and Soy Products

The Paleo Diet

Consumers beware! Notice that the concentration of saponins in soy protein isolates is dangerously high.  If you are an athlete or anyone else trying to increase your protein intake by supplementing with soy protein isolates, I suggest that you reconsider.  A much healthier strategy would be to eat more meats, fish and seafood.  These protein packed foods taste a whole lot better than artificial soy isolates and are much better for your body.  If we only eat legumes occasionally,  saponin damage to our intestines will quickly repair itself, however when legumes or soy products are consumed in high amounts as staples or daily supplements, the risk for a leaky gut and the diseases associated with it is greatly increased.

Phytate

We’ve already discussed this antinutrient in great detail, so there is really not much else to say.  Because phytate prevents the full absorption of iron, zinc, calcium, magnesium and copper present in legumes and whole grains, then reliance upon these plant foods frequently causes multiple nutritional deficiencies in adults, children and even nursing infants.  Boiling and cooking don’t seem to have much effect upon the phytate content of legumes, whereas sprouting and fermentation can moderately reduce phytate concentrations. Also, vitamin C counteracts phytate’ s inhibitory effects on mineral absorption.  Nevertheless, the best tactic to reduce phytate in your diet is to adopt The Paleo Diet – humanity’s original legume and grain free diet.

Polyphenols: Tannins and Isoflavones

Polyphenols are antioxidant compounds that protect plants from UV sunlight damage as well as from insects, pests and other microorganisms.  Just like sunscreens protect our skin from UV damage, polyphenols are one of the compounds plants have evolved to escape the harmful effects of ultraviolet (UV) radiation from the sun, along with damage caused by animal and microorganism predators.  Polyphenols come in many different varieties and forms and are common throughout the plant kingdom.  When we eat these compounds, they seem to have both healthful and detrimental effects in our bodies.  For instance, resveratrol is a polyphenol found in red wine that may increase lifespan in mice and slow or prevent many diseases.    On the other hand, at least two types of polyphenols (tannins and isoflavones) within beans, soy and other legumes may have adverse effects in our bodies (59).

Tannins are bitter tasting polyphenols and give wine its astringent qualities.  As with all antinutrients, the more tannin you ingest, the greater is the potential to disrupt your health.   Tannins are similar to phytate in that they reduce protein digestibility and bind iron and other minerals, thereby preventing their normal absorption (29, 59).  Some, but not all tannins damage our intestines causing a “leaky gut” (59).   By now you can see that legumes, beans and soy represent a triple threat to our intestinal integrity since three separate antinutrients (lectins, saponins, and tannins) all work together to encourage a leaky gut. Let’s move on to the next category of polyphenols.

Isoflavones are some of nature’s weirder plant compounds in that they act like female hormones in our bodies.  Certain isoflavones which are concentrated in soybeans and soy products are called phytoestrogens – literally meaning, “plant estrogens”.  I’ve previously mentioned that isoflavones from soy products can cause goiters (an enlargement of the thyroid gland), particularly if your blood levels of iodine are low.  Two phytoestrogens in soy called genistein and daidzen produce goiters in experimental animals.  You don’t have to develop full blown goiters by these soy isoflavones to impair your health.  In a study of elderly subjects, Dr. Ishizuki (31) and colleagues demonstrated that when subjects (average age, 61 years) were given 30 grams of soy daily for three months they developed symptoms of low thyroid function (malaise, lethargy, and constipation), and half of these people ended up with goiters.

For women, regular intake of soy or soy isoflavones may disrupt certain hormones that regulate the normal menstrual cycle.  In a meta analysis of 47 studies, Dr. Hooper and co-workers (28) demonstrated that soy or soy isoflavones consumption caused two female hormones, follicle stimulating hormone (FSH) and luteinizing hormone (LH), to fall by 20 %.  The authors concluded, “The clinical implications of these modest hormonal changes remain to be determined.”

I wouldn’t necessary agree with this conclusion, nor would I call a 20 % reduction in both FSH and LH “modest”.  In one study, seven of nine women who consumed vegetarian diets (containing significant quantities of legumes) for only six weeks stopped ovulating (69).  One of the hormonal changes reported in this study, concurrent with the cessation of normal periods, was a significant decline in luteinizing hormone (LH).  Because western vegetarian diets almost always contain lots of soy and hence soy isoflavones, it is entirely possible that soy isoflavones were directly responsible for the declines in LH and the disruption of normal menstrual periods documented in this study.

I have received email from women all over the world who’s menstrual and infertility problems subsided after adopting The Paleo Diet (see Chapter 13). Their stories paint a credible picture that modern day Paleo Diets contain multiple nutritional elements that may improve or eliminate female reproductive and menstrual problems.  Unfortunately scientific validation of these women’s experiences still lies in the future.

Perhaps the most worrisome effects of soy isoflavones may occur in developing fetuses with iodine deficient mothers and in infants receiving soy formula.  A recent (2007) paper by Dr. Gustavo Roman (54) at the University of Texas Health Sciences Center has implicated soy isoflavones as risk factors for autism via their ability to impair normal iodine metabolism and thyroid function.  Specifically, the soy isoflavone known as genistein may inhibit a key iodine based enzyme required for normal brain development.  Pregnant women with borderline iodine status can become iodine deficient by consuming a high soy diet.  Their deficiency may then be conveyed to their developing fetus which in turn impairs growth in fetal brain cells known to be involved in autism.  Infants born with iodine deficiencies are made worse if they are fed a soy formula.  Once again, the evolutionary lesson repeats itself.  If a food or nutrient generally was not a part of our ancestral diet, it has a high probability of disrupting our health and that of our children.

Protease Inhibitors

Unless you are a biologist by trade or are involved in a very narrow area of human nutrition, very few people on the planet know about protease inhibitors.  But I can tell you that when you eat beans, soy or other legumes you should be as aware of protease inhibitors as you are of a radar trap on the freeway – that is – if you don’t want to get a ticket or eat foods that can have unfavorably effects upon your health.

When we eat any protein, we have enzymes in our intestines which break protein into its component amino acids.  These enzymes are called proteases and must be operating normally for our bodies to properly assimilate dietary proteins.  Almost all legumes are concentrated sources of antinutrients called protease inhibitors which prevent our gut enzymes from degrading protein into amino acids.  Protease inhibitors found in beans, soy, peanuts and other legumes are part of the reason why legume proteins have lower bioavailability than meat proteins (20).  In experimental animals ingestion of protease inhibitors in high amounts depresses normal growth and causes pancreatic enlargement (21, 39, 41).  Heating and cooking effectively destroys about 80 % of protease inhibitors found in most legumes (5, 11), so the dietary concentrations of these antinutrients found in beans and soy are thought to have little harmful effects in our bodies.  Nevertheless, at least one important adverse effect of protease inhibitors may have been overlooked.

When the gut’s normal protein degrading enzymes are inhibited by legume protease inhibitors, the pancreas works harder and compensates by secreting more protein degrading enzymes.  Consequently, consumption of protease inhibitors causes levels of protein degrading enzymes to rise within our intestines.  One enzyme in particular, called trypsin, increases significantly.  The rise in trypsin concentrations inside our gut is not without consequence, because elevated trypsin levels increase intestinal permeability in animal experiments (53).  Once again we see yet another antinutrient found in legumes that contribute to a leaky gut, which as I have explained early is not without consequence.

Raffinose Oligosaccharides

Here’s another big scientific term for a little problem almost every one of us has had to deal with at one time or another after we ate beans.  Beans cause gas or flatulence.  Almost all legumes contain complex sugars called oligosaccharides.  In particular, two complex sugars (raffinose and stachyose) are the culprits and are the elements in beans that give us gas (6).  We lack the gut enzymes to breakdown these complex sugars into simpler sugars.  Consequently, bacteria in our intestines metabolize these oligosaccharides into a variety of gases (hydrogen, carbon dioxide and methane).  Beans don’t affect us all equally.  Some people experience extreme digestive discomfort with diarrhea, nausea, intestinal rumbling and flatulence, whereas others are almost symptomless (6).  These differences among people seem to be caused by varying types of gut flora (microorganisms).

Cyanogenetic Glycosides

Upon digestion, antinutrients in lima beans called cyanogenetic glycosides are turned into the lethal poison, hydrogen cyanide, in our intestines.  Fortunately, cooking eliminates most of the hydrogen cyanide in lima beans.  Nevertheless a number of fatal poisonings have been reported in the medical literature from people eating raw or undercooked lima beans (70).

Although most of us would never consider eating raw lima beans, the problem doesn’t end here.  Upon cooking most of the hydrogen cyanide in lima beans is converted into a compound called thiocyanate which you can add to soy isoflavones as dietary antinutrients that impair iodine metabolism and cause goiter (70).  In iodine deficient children, these so-called goitrogens are suspect dietary agents underlying autism (54).

Favism  Glycosides

Unless you are a bean connoisseur, most of us in the United States have never tasted broad beans which are also known as fava or faba beans.  In Mediterranean, Middle Eastern and North African countries broad beans are more popular.  Unfortunately, for many people in these countries, particularly young children, consumption of fava beans can be lethal.  It has been intuitively known for centuries that fava bean consumption was fatal in certain people.  However, the biochemistry of the disease (called favism) has only been worked out in the past 50 years or so (7).

Favism can only occur in people with a genetic defect called G6PD deficiency.  This mutation is the most common human enzyme defect – being present in more than 400 million people worldwide.   It is thought to confer protection against malaria.  People whose genetic background can be traced to Italy, Greece, the Middle East or North Africa are at a much higher risk for carrying this mutation.  If you or your children don’t know if you have the genes causing favism, a simple blood test available at most hospitals and medical clinics can diagnose this problem.  Consumption of fava beans in genetically susceptible people causes a massive rupturing of red blood cells called hemolytic anemia and may frequently be fatal in small children unless blood transfusions are made immediately (7, 71).  Not all people with G6PD deficiency experience favism symptoms after they eat broad beans; however if your family background is from the Mediterranean region you may be particularly susceptible.

Although it is not completely known how broad bean consumption causes favism, three antinutrient glycosides (divicine, isouramil and convicine) found in these legumes likely do the damage (72).  These compounds enter our bloodstreams, and in people with the G6PD mutations interact with red blood cells in a manner that causes them to rupture.   So, you can now add fava beans along with lima beans to the list of legumes which are lethally toxic.

Peanuts and Heart Disease

What’s wrong with Peanut Oil and Peanuts?  Most nutritional experts would tell us that they are heart healthy foods because they contain little saturated fat and most of their fat is made up of cholesterol lowering monounsaturated and polyunsaturated fats.  Hence, on the surface, you might think that peanut oil would probably be helpful in preventing the artery clogging process (atherosclerosis) that underlies heart disease.  Your thoughts were not much different from those of nutritional scientists – that is until they actually tested peanuts and peanut oil in laboratory animals.  Starting in the 1960’s and continuing into the 1980’s scientists unexpectedly found peanut oil to be highly atherogenic, causing arterial plaques to form in rabbits, rats and primates (73-78) – only a single study (79) showed otherwise.  Peanut oil was found to be so atherogenic that it continues to be routinely fed to rabbits to produce atherosclerosis to study the disease itself.

Initially, it was unclear how a seemingly healthful oil could be so toxic in such a wide variety of animals.  Dr. David Kritchevsky and co-workers at the Wistar Institute in Philadelphia were able to show with a series of experiments that peanut oil lectin (PNA) was most likely responsible for it artery clogging properties (36, 37).  Lectins are large protein molecules and most scientists had presumed that digestive enzymes in the gut would degrade it into its component amino acids.  Consequently, it was assumed that the intact lectin molecule would not be able to get into the bloodstream to do its dirty work.  But they were wrong.  It turned out that lectins were highly resistant to the gut’s protein shearing enzymes.  An experiment conducted by Dr. Wang and colleagues and published in the prestigious medical journal Lancet (64) revealed that PNA got into the bloodstream intact in as little 1-4 hours after subjects ate a handful of roasted, salted peanuts.   Even though the concentrations of PNA in the subject’s blood were quite low, they were still at concentrations known to cause atherosclerosis in experimental animals.  Lectins are a lot like super glue – it doesn’t take much.  Because these proteins contain carbohydrates, they can bind to a wide variety of cells in the body, including the cells lining the arteries.  And indeed, it was found that PNA did its damage to the arteries by binding to a specific sugar receptor (58).  So, the practical point here is to stay away from both peanuts and peanut oil and all legumes.

 Summary

I’d like to make a final departing comment before we leave the topic of beans and legumes.  As you adopt The Paleo Diet or any diet, listen to your body.  If a food or food type doesn’t agree with you or makes you feel ill or unwell, don’t eat it.  I should have listened to my own advice 25 years ago when I was experimenting with vegetarian diets.  Whenever I ate beans or legumes, I experienced digestive upset, gas and frequently had diarrhea.   Since embracing The Paleo Diet almost 20 years ago, these symptoms have become a thing of the past.

Cordially,

Loren Cordain, Ph.D., Professor Emeritus

REFERENCES

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2. Banwell, JG, Howard R, Kabir I, Costerton JW.   Bacterial overgrowth by indigenous microflora in the phytohemagglutinin-fed rat. Canadian Journal of  Microbiology. 1988; 34:1009-13.

3. Baumann E, Stoya G, Völkner A, Richter W, Lemke C, Linss W. Hemolysis of human erythrocytes with saponin affects the membrane structure. Acta Histochem. 2000 Feb;102(1):21-35.

4. Boufassa C, Lafont J, Rouanet J M, Besancon P 1986 Thermal inactivation of lectins (PHA)isolated from Phaseolus vulgaris. Food Chem 20 295-304.

5. Buera M P, Pilosof A M R, Bartholomai G B 1984 Kinetics of trypsin inhibitory activity loss in heated flour from bean Phaseolus vulgaris. J Food Sci 49 124-126.

6. Calloway DH, Carol A. Hickey CA,  Murphy EL. Reduction of intestinal gas-forming properties of legumes by traditional and experimental processing methods. J Food Sci. 1971;  36: 251-255.

7. Cappellini MD, Fiorelli G. Glucose-6-phosphate dehydrogenase deficiency. Lancet 2008;371(9606): 64–74.

8. Carmalt J, Rosel K, Burns T, Janzen E. Suspected white kidney bean (Phaseolus vulgaris) toxicity in horses and cattle. Aust Vet J. 2003 Nov;81(11):674-6.

9. Caron, M. & Steve, A.P. Lectins and Pathology, Taylor & Francis, 2000, London.

10. Chrispeels, M.J. & Raikel, N.V. (1991) Lectins, lectin genes, and their role in plant defense. Plant Cell 3, 1-9.

11. Collins J L, Beaty B F 1980 Heat inactivation of trypsin inhibitor in fresh green soybeans and physiological responses of rats fed the beans. J Food Sci 45 542-546.

12. Cordain L, Toohey L, Smith MJ, Hickey MS. Modulation of immune function by dietary lectins in rheumatoid arthritis. Br J Nutr. 2000 Mar;83(3):207-17.

13. Couzy F, Mansourian R, Labate A, Guinchard S, Montagne DH, Dirren H. Effect of dietary phytic acid on zinc absorption in the healthy elderly, as assessed by serum concentration curve tests. Br J Nutr. 1998 Aug;80(2):177-82.

14. FAO/WHO Expert Consultation. Protein Quality Evaluation. Food and Agricultural Organization of the United Nations, FAO Food and Nutrition Paper 51, Rome.

15. Firestein GS, Alvaro-Gracia JM, Maki R.  Quantitative analysis of cytokine gene expression in rheumatoid arthritis. Journal of  Immunology. 1990;144: 33347-53.

16. Francis G, Kerem Z, Makkar HP, Becker K. The biological action of saponins in animal systems: a review. Br J Nutr. 2002 Dec;88(6):587-605.

17. Gee JM, Johnson IT. Interactions between hemolytic saponins, bile salts and small intestinal mucosa in the rat. J Nutr. 1988 Nov;118(11):1391-7.

18. Gee JM, Wal JM, Miller K, Atkinson H, Grigoriadou F, Wijnands MV, Penninks AH, Wortley G, Johnson IT. Effect of saponin on the transmucosal passage of beta-lactoglobulin across the proximal small intestine of normal and beta-lactoglobulin-sensitised rats. Toxicology. 1997 Feb 28;117(2-3):219-28.

19. Gibson RS, Bailey KB, Gibbs M, Ferguson EL. A review of phytate, iron, zinc, and calcium concentrations in plant-based complementary foods used in low-income countries and implications for bioavailability. Food Nutr Bull. 2010 Jun;31(2 Suppl):S134-46.

20. Gilani GS, Cockell KA, Sepehr E. Effects of antinutritional factors on protein digestibility and amino acid availability in foods. J AOAC Int. 2005 May-Jun;88(3):967-87.

21. Grant G. Anti-nutritional effects of soyabean: a review. Prog Food Nutr Sci. 1989;13(3-4):317-48.

22. Grant G, More LJ, McKenzie NH, Stewart JC, Pusztai A. A survey of the nutritional and haemagglutination properties of legume seeds generally available in the UK. Br J Nutr. 1983 Sep;50(2):207-14.

23. Grant G, More LJ, McKenzie NH, Pusztai A. The effect of heating on the haemagglutinating activity and nutritional properties of bean (Phaseolus vulgaris) seeds. J Sci Food Agric 1982;33: 1324-1326.

24. Greer F,  Pusztai A. (1985).  Toxicity of kidney bean (Phaseolus vulgaris) in rats: changes in intestinal permeability. Digestion. 1985 32: 42-46.

25. Gupta YP. Anti-nutritional and toxic factors in food legumes: a review. Plant Foods Hum Nutr 1987;37:201-228.

26. Hallberg L, Hulthén L. Prediction of dietary iron absorption: an algorithm for calculating absorption and bioavailability of dietary iron. Am J Clin Nutr. 2000 May;71(5):1147-60.

27. Hintz HF, Hogue DE, Krook L. Toxicity of red kidney beans (Phaseolus vulgaris) in the rat. J Nutr. 1967 Sep;93(1):77-86

28. Hooper L, Ryder JJ, Kurzer MS, Lampe JW, Messina MJ, Phipps WR, Cassidy A. Effects of soy protein and isoflavones on circulating hormone concentrations in pre- and post- enopausal women: a systematic review and meta-analysis. Hum Reprod Update. 2009 Jul-Aug;15(4):423-40.

29. Hughes JS, Acevedo E, Bressani R, Swanson BG.  Effects of dietary fiber and tannins on protein utilization in dry beans (Phaseolus vulgaris). Food Res Int 1996;29:331-338.

30. Hurrell RF, Juillerat MA, Reddy MB, Lynch SR, Dassenko SA, Cook JD. Soy protein, phytate, and iron absorption in humans. Am J Clin Nutr. 1992 Sep;56(3):573-8.

31. Ishizuki Y, Hirooka Y, Murata Y, Togashi K.  The effects on the thyroid gland of soybeans administered experimentally in healthy subjects. Nippon Naibunpi Gakkai Zasshi. 1991 May 20;67(5):622-9.

32. Johnson IT, Gee JM, Price K, Curl C, Fenwick GR. Influence of saponins on gut permeability and active nutrient transport in vitro. J Nutr. 1986 Nov;116(11):2270-7.

33. Keukens EA, de Vrije T, van den Boom C, de Waard P, Plasman HH, Thiel F, Chupin V, Jongen WM, de Kruijff B. Molecular basis of glycoalkaloid induced membrane disruption. Biochim Biophys Acta. 1995 Dec 13;1240(2):216-28.

34. Kilpatrick DC, Pusztai A, Grant G, Graham C, Ewen SW. Tomato lectin resists digestion in the mammalian alimentary canal and binds to intestinal villi without deleterious effects. FEBS Lett. 1985;185:299-305

35. Knudsen D, Jutfelt F, Sundh H, Sundell K, Koppe W, Frøkiaer H. Dietary soya saponins increase gut permeability and play a key role in the onset of soyabean-induced enteritis in Atlantic salmon ( Salmo salar L.). Br J Nutr. 2008 Jul;100(1):120-9.

36. Kritchevsky D et al.  Influence of native and randomized peanut oil on lipid metabolism and aortic sudanophilia in the vervet monkey. Atherosclerosis 1982;42:53-58.

37. Kritchevsky D, Tepper SA, Klurfeld DM. Lectin may contribute to the atherogenicity of peanut oil. Lipids 1998 Aug;33(8):821-3

38. Liener IE.   Nutritional significance of lectins in the diet.  In The Lectins: Properties, Functions, and Applications in Biology and Medicine, pp. 527-52 [I.E. Liener, N. Sharon, I.J. Goldstein, editors]. Orlando; Academic Press, 1986.

39. Liener IE (1994) “Implications of antinutritional components in soybean foods.” Crit Rev Food Sci Nutr., vol. 34, pp. 31-67.

40. Lochner N, Pittner F, Wirth M, Gabor F. Wheat germ agglutinin binds to the epidermal growth factor receptor of artificial Caco-2 membranes as detected by silver nanoparticle enhanced fluorescence. Pharm Res. 2003 May;20(5):833-9

41. Losso JN. The biochemical and functional food properties of the bowman-birk inhibitor. Crit Rev Food Sci Nutr. 2008 Jan;48(1):94-118.

42. Noah ND, Bender AE, Reaidi GB, Gilbert RJ. Food poisoning from raw red kidney beans. BrMed J. 1980 Jul 19;281 (6234):236-7.

43. Muraille E, Pajak B, Urbain J, Leo O. Carbohydrate-bearing cell surface receptors involved in innate immunity: interleukin-12 induction by mitogenic and nonmitogenic lectins. Cell Immunol. 1999 Jan 10;191(1):1-9.

44. Pusztai A, Clarke EM, Grant G, King TP. The toxicity of Phaseolus vulgaris lectins. Nitrogen balance and immunochemical studies. J Sci Food Agric. 1981 Oct;32(10):1037-46.

45. Pusztai A, Greer F & Grant G. Specific uptake of dietary lectins into the systemic circulation of rats. Biochemical Society Transcations. 1989;17, 527-528

46. Pusztai A, Grant G.  Assessment of lectin inactivation by heat and digestion. In: Methods in Molecular Medicine: Vol. 9: Lectin methods and protocols.  J M Rhodes, JM, J D Milton JD (Eds). Humana Press Inc. Totowa, NJ, 1998.

47. Pusztai A, Ewen SW, Grant G, Brown DS, Stewart JC, Peumans WJ, Van Damme EJ, Bardocz S. Antinutritive effects of wheat-germ agglutinin and other N-acetylglucosamine-specific lectins. Br J Nutr. 1993 Jul;70(1):313-21

48. Pusztai A.. Dietary lectins are metabolic signals for the gut and modulate immune and hormone functions. European Journal of Clinical Nutrition. 1993;47: 691-99.

49. Pusztai A, Ewen  SWB, Grant G, Peumans WJ, Van Damme EJM, Rubio LA, Bardocz S. Plant (food) lectins as signal molecules: Effects on the morphology and bacterial ecology of the small intestine.  In Lectin Reviews, Volume I , pp. 1-15 [D.C. Kilpatrick, E. Van Driessche, T.C. Bog-Hansen, editors].  St. Louis: Sigma, 1991.

50. Pusztai A, Grant G, Spencer RJ, Duguid TJ, Brown DS, Ewen, SWB, Peumans WJ, Van Damme EJM, Bardocz S.  Kidney bean lectin-induced Escherichia coli overgrowth in the small intestine is blocked by GNA, a mannose-specific lectin. Journal of Applied Bacteriology. 1993;75: 360-68.

51. Rattray EAS, Palmer R, Pusztai A. Toxicity of kidney beans (Phaseolus vulgaris L.) to conventional and gnotobiotic rats. Journal of the Science of  Food and Agriculture. 1974; 25:1035-40.

52. Rodhouse JC, Haugh CA, Roberts D, Gilbert RJ. Red kidney bean poisoning in the UK: an analysis of 50 suspected incidents between 1976 and 1989. Epidemiol Infect. 1990 Dec;105(3):485-91.

53. Róka R, Demaude J, Cenac N, Ferrier L, Salvador-Cartier C, Garcia-Villar R, Fioramonti J, Bueno L. Colonic luminal proteases activate colonocyte proteinase-activated receptor-2 and regulate paracellular permeability in mice. Neurogastroenterol Motil. 2007 Jan;19(1):57-65.

54. Román GC. Autism: transient in utero hypothyroxinemia related to maternal flavonoid ingestion during pregnancy and to other environmental antithyroid agents. J Neurol Sci. 2007 Nov 15;262(1-2):15-26

55. Ruiz RG, Price KR, Arthur AE, Rose ME, Rhodes MJ, Fenwick RG.  Effect of soaking and cooking on saponin content and composition of chickpeas (Cicer arietinum) and lentils (Lens culinaris). J Agric Food Chem 1996;44:1526-30.

56. Ryder SD, Smith JA, Rhodes JM.  Peanut lectin: a mitogen for normal human colonic epithelium and human HT29 colorectal cancer cells. Journal of the National Cancer Institute. 1992;84:1410-16.

57. Sandberg AS. Bioavailability of minerals in legumes. Br J Nutr. 2002 Dec;88 Suppl 3:S281-5.

58. Sanford GL, Harris-Hooker S.  Stimulation of vascular proliferation by beta-galactoside specific lectins. FASEB J 1990;4:2912-2918.

59. Singleton VL. Naturally occurring food toxicants: phenolic substances of plant origin. Adv Food Res. 1981;27:149-242.

60. Tuxen MK, Nielsen HV, Birgens H.  [Poisoning by kidney beans (Phaseolus vulgaris)]. Ugeskr Laeger. 1991 Dec 16;153(51):3628-9.

61.  U.S.D.A. Choose My Plate.

62. van den Bourne BE, Kijkmans BA, de Rooij HH, le Cessie S, Verweij CL. Chloroquine and hydroxychloroquine equally affect tumor necrosis factor-alpha, interleukin 6, and interferon-gamma production by peripheral blood mononuclear cells. Journal of Rheumatology. 1997;24: 55-60.

63. Venter FS, Thiel PG. Red kidney beans–to eat or not to eat? S Afr Med J. 1995 Apr;85(4):250-2.

64. Wang Q, Yu LG, Campbell BJ, Milton JD, Rhodes JM. Identification of intact peanut lectin in peripheral venous blood. Lancet. 1998;352:1831-2

65. Wilson AB, King TP, Clarke EMW, Pusztai A.   Kidney bean (Phaseolus vulgaris) lectin-induced lesions in the small intestine. II. Microbiological studies. Journal of  Comparitive Pathology. 1980; 90:597-602.

66. Nutritionist Pro Dietary Software. http://www.nutritionistpro.com/

67. Fasano A. Leaky gut and autoimmune diseases. Clin Rev Allergy Immunol. 2012 Feb;42(1):71-8

68. Piya MK, Harte AL, McTernan PG. Metabolic endotoxaemia: is it more than just a gut feeling? Curr Opin Lipidol. 2013 Feb;24(1):78-85.

69. Pirke KM, Schweiger U, Laessle R, Dickhaut B, Schweiger M, Waechtler M. Dieting influences the menstrual cycle: vegetarian versus nonvegetarian diet. Fertil Steril. 1986 Dec;46(6):1083-8

70. Conn EE. Cyanogenic glycosides.  In:  Encyclopedia of Plant Physiology. New Series. Volume 8. Secondary plant products [Bell, A.E.; Charlwood, B.V. (Editors)]. 1980 pp. 461-492

71. Schuurman M, van Waardenburg D, Da Costa J, Niemarkt H, Leroy P.Severe hemolysis and methemoglobinemia following fava beans ingestion in glucose-6-phosphatase dehydrogenase deficiency: case report and literature review. Eur J Pediatr. 2009 Jul;168(7):779-82

72. Arese P, Bosia A, Naitana A, Gaetani S, D’Aquino M, Gaetani GF. Effect of divicine and isouramil on red cell metabolism in normal and G6PD-deficient (Mediterranean variant) subjects. Possible role in the genesis of favism. Prog Clin Biol Res. 1981;55:725-46

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74. Scott RF et al.  Short term feeding of unsaturated vs. satruated fat in the production of atherosclerosis and thrombosis in the rat. Exp Mol Pathol 1964;3:421-443.

75. Wissler RW et al. Aortic lesions and blood lipids in monkeys fed three food fats. Fed Proc 1967;26:371.

76. Kritchevsky D et al.  Influence of native and randomized peanut oil on lipid metabolism and aortic sudanophilia in the vervet monkey. Atherosclerosis 1982;42:53-58.

77. Kritchevsky D et al. Lipid metabolism and experimental atherosclerosis in baboons– influence of cholesterol free, semi-synthetic diets. Am J Clin Nutr 1974;27:29-50.

78. Boyle EM et al.  Atherosclerosis. Ann Thorac Surg 1997;64:S47-56.

79. Alderson LM et al.  Peanut oil reduces diet-induced atherosclerosis in cynomolgus monkeys.   Arteriosclerosis 1986;6:465-74.

Betaine | The Paleo Diet
The modern Paleo Diet is focused on lean meats, but we love vegetables too. However, many Westerners need to beef up their vegetable intake because over 87% of adults are not eating enough of them each day.1 Although, the Paleo Diet favors foods with a lower glycemic impact, 2 you can’t beat the nutritional benefits of beets. They are rich in calcium, iron, magnesium, vitamin C, potassium, manganese, phosphorous, as well as carotene and B complex.3 Beets provide anti-inflammatory, antioxidant and detox support in the body. They also support healthy bile flow,4 stimulate liver cell function, and provide a protective effect for the liver and bile ducts.5

Beets are a great source of betaine, also called betaine anhydrous or trimethylglycine (TMG). Betaine is a substance that’s made in the body that’s required for healthy liver function, cellular reproduction, and to make carnitine.6 Further, there is a growing body of evidence that betaine is an important nutrient for the prevention of chronic disease.7 It is also a metabolite of choline8 and an essential biochemical component of the methionine-homocysteine cycle.9

Specifically, betaine also plays a role in reducing levels of the amino acid homocysteine in the blood.10 Homocysteine is a toxic substance in the body that can lead to osteoporosis and is an indicator of an increased risk of heart disease.11

Beets are a great alternative for endurance athletes looking for a nutrient dense option for post workout food to replenish from workouts.12 Studies have shown that eating beets prior to exercise, led to a 16% increase in workout times.13 They are also rich in antioxidants14 to aid in recovery between exercise sessions. Whether you are an avid exerciser or not, adding beets to your Paleo Diet is a win-win as they are a nutritional powerhouse.

Although typically eaten cooked, beets can also be eaten raw. Thinly slice or grate and serve over dressed lettuce greens. To roast whole beets, place them in a covered roasting pan for 45-60 minutes (until you can pierce them with a fork) in a 375 °F oven. Once cooked, the skin will easily peel away with your fingers.

This hearty, Paleo Roasted Beet and Tomato Soup offers a simple way to introduce cooked beets into your Paleo Diet.  It is a festive, bright dish to commence any holiday meal or as an accompaniment to your favorite Paleo sandwich.

Paleo Roasted Red Beet & Tomato Soup

Paleo Soup | The Paleo Diet

Serves 4

Ingredients

  • 1 tablespoon coconut oil
  • 1 red onion, sliced
  • 1 small carrot, diced
  • 2 (14.5 oz.) cans of no salt added organic diced tomatoes or homemade canned tomatoes
  • 1 large roasted, peeled, red beet (about 2 cups cubed)
  • Black pepper to taste

Directions

  1. Sauté the red onion and carrot in the coconut oil until the onions turn translucent and the carrot is soft.
  2. In a blender, combine the diced tomatoes, the cubed roasted beet, and the cooked onion mixture.
  3. Blend until very smooth.
  4. Pour the mixture into a soup pot.
  5. Simmer for 10-20 minutes, season with black pepper to taste and serve!

References

1. Available at: http://epi.grants.cancer.gov/diet/usualintakes/pop/2007-10/. Accessed on November 8, 2015.

2. Cordain, Loren. The Paleo Diet Revised: Lose Weight and Get Healthy by Eating the Foods You Were Designed to Eat. Houghton Mifflin Harcourt, 2010.

3. Available at: http://nutritiondata.self.com/facts/vegetables-and-vegetable-products/2348/2. Accessed on November 8, 2015.

4. Gu, X., and D. Li. “Fat nutrition and metabolism in piglets: a review.” Animal Feed Science and Technology 109.1 (2003): 151-170.

5. Kanbak, Güngör, Mine İnal, and Cengiz Bayçu. “Ethanol‐induced hepatotoxicity and protective effect of betaine.” Cell biochemistry and function 19.4 (2001): 281-285.

6. Craig, Stuart AS. “Betaine in human nutrition.” The American journal of clinical nutrition 80.3 (2004): 539-549.

7. Craig, Stuart AS. “Betaine in human nutrition.” The American journal of clinical nutrition 80.3 (2004): 539-549.

8. Abdelmalek, Manal F., et al. “Betaine, a promising new agent for patients with nonalcoholic steatohepatitis: results of a pilot study.” The American journal of gastroenterology 96.9 (2001): 2711-2717.

9. Craig SA. Betaine in human nutrition. Am J Clin Nutr 80: 539–549, 2004.

10. Olthof, Margreet R., et al. “Low dose betaine supplementation leads to immediate and long term lowering of plasma homocysteine in healthy men and women.” The Journal of nutrition 133.12 (2003): 4135-4138.

11. Homocysteine Studies Collaboration. “Homocysteine and risk of ischemic heart disease and stroke: a meta-analysis.” Jama 288.16 (2002): 2015-2022.

12. Lomangino, Kevin. “Moving With the Beet: Can It Enhance Athletic Performance?.” Clinical Nutrition Insight 38.9 (2012): 6-7.

13. Bailey, Stephen J., et al. “Dietary nitrate supplementation reduces the O2 cost of low-intensity exercise and enhances tolerance to high-intensity exercise in humans.” Journal of Applied Physiology 107.4 (2009): 1144-1155.

14. Trejo-Tapia, G., et al. “Effect of screening and subculture on the production of betaxanthins in Beta vulgaris L. var.‘Dark Detroit’callus culture.” Innovative Food Science & Emerging Technologies 9.1 (2008): 32-36.

Eliminate Food Groups | The Paleo Diet
Do you believe that “our modern lifestyles, including nutrition, are the cause of current health problems?” If so, you could be susceptible to “fad diets,” according to the United Dairy Industry of Michigan (UDIM). Last week, the organization’s Technical Advisor for Nutrition, Lois McBean, wrote that those who follow the Paleo diet “are likely setting themselves up for nutritional deficiencies by eliminating entire food groups such as dairy, grains, and legumes.”1

McBean went on to observe, “Such restrictive diets are not consistent with current dietary recommendations including USDA’s MyPlate or the 2010 Dietary Guidelines for Americans.” It’s interesting that she invokes the 2010 Guidelines, considering that earlier this year, the Dietary Guidelines Advisory Committee (DGAC) acknowledged that the 2010 and previous Guidelines contain a glaring error.

In the DGAC’s own words, “Previously, the Dietary Guidelines for Americans recommended that cholesterol intake be limited to no more than 300 mg/day. The 2015 DGAC will not bring forward this recommendation because available evidence shows no appreciable relationship between consumption of dietary cholesterol and serum cholesterol.”2

The 2010 and previous Guidelines were wrong about cholesterol, a mistake that likely persuaded millions of people to avoid eggs, shrimp, and other healthy, cholesterol-rich foods. Is it conceivable that the Guidelines could also be wrong about dairy, cereals, and legumes? We’ll address this question, but first let’s examine the idea of “eliminating entire food groups.”

Eliminating Entire Food Groups

Paleo critics like McBean seem to think the USDA’s MyPlate is inclusive of all food groups, but surprisingly, it excludes the most nutrient dense food group of them all – organ meat. The Paleo diet, on the other hand, excludes dairy, cereals, and legumes because, despite the nutrients they contain, they also contain antinutrients and promote various adverse health effects. But what possible reason could the USDA and Paleo critics have for excluding organ meat?

In the US, organ meat fell out of favor decades ago, but in most other countries it’s embraced and recognized for its remarkably high nutrient levels. Those who worry about nutrient deficiencies should be questioning the exclusion of organ meat (an entire food group) before criticizing those who, for valid reasons, exclude dairy, cereals, and legumes.

Nutrient Deficiencies

McBean lauds dairy foods as “important sources of multiple essential nutrients, including calcium, vitamin D, and potassium,” while implying that the Paleo diet falls short on these nutrients. This is an interesting comment for three reasons:

1. Dairy is not a rich source of potassium

The charts below show potassium, vitamin D, and calcium levels for 100g portions of common foods. Paleo foods are highlighted in orange, non-Paleo foods in purple. All values are for uncooked foods; note that 100g doesn’t necessarily represent a serving size. For example, beans are richest in potassium, but once cooked, potassium is significantly diluted because the beans absorb so much water. As shown, Paleo foods, including vegetables, seeds, nuts, mushrooms, fruit, fish, and meat, provide plenty of potassium.

How much potassium is enough? The National Academy of Sciences (NAS) sets the Daily Recommended Intake (DRI) for all nutrients. For potassium, however, instead of a DRI they set an Adequate Intake (AI) level of 4.7g per day. The NAS notes, “dietary intake of potassium by all groups in the United States and Canada is considerably lower than the AI.”3 With so many potassium-rich foods to choose from (note: the chart is not comprehensive), the Paleo diet emerges as the solution for potassium deficiency, not the cause.

Potassium | The Paleo Diet

2. Most of dairy’s vitamin D comes through fortification

Vitamin D | The Paleo Diet[/one_half]

Dairy fat does contain a small amount of natural vitamin D, but non-fat and low-fat dairy have almost none. As shown in the chart, the foods highest in vitamin D are Paleo foods, namely fish, shrimp, eggs, and to a lesser degree organ meat and mushrooms. Even fortified dairy doesn’t provide spectacular amounts.

Furthermore, if you want to go the fortification route, you’re much better off with vitamin D supplements, in which case you could avoid the negative effects of dairy. Note that the DRI for vitamin D is 600 IU/day.

3. Dairy is indeed high in calcium, but the calcium story is nuanced

As Dr. Cordain has explained extensively, net calcium balance (NCB) is far more important than calcium intake. NCB equals calcium intake minus calcium excretion. Calcium excretion is largely a function of acid/alkaline balance. For diets with net acid loads, the body’s calcium salts, which are stored within the bones, are excreted to maintain balance. For diets with net alkaline loads, endogenous calcium stores are unaffected.

Calcium | The Paleo DietThe only alkalizing foods are vegetables and fruit. The Paleo diet is more alkaline than MyPlate because of its emphasis on vegetables and its exclusion of dairy, cereals, and legumes. As shown in the chart, calcium in the Paleo diet comes from seeds, nuts, bones, vegetables, and from the fact that proportionally less calcium is excreted, due to the diet’s alkalinity. Note that the DRI for calcium is 1,000 mg/day.

Despite its calcium levels, dairy causes more problems than it solves. According to the US National Library of Medicine, an estimated 65% of the global population is lactose intolerant.4 Additionally, drinking 3 cups of milk per day, as McBean and the UDIM recommend, is associated with an increased risk of bone fractures as well as increased overall mortality, according to a cohort study published by the British Medical Journal.5 This study was observational, so it cannot prove causation, but it underscores the net acid load problem and other problems associated with dairy.

Far from promoting nutrient deficiencies, a careful examination of the evidence shows the Paleo diet reverses nutrient deficiencies caused by junk food and other imbalanced diets. This is accomplished by eliminating problematic food groups, including dairy, cereals, and legumes, while embracing the healthiest food groups, including meat, fish, organ meat, vegetables, nuts/seeds, and fruit.

References

1. McBean, L. (November 4, 2015). Fad Diets: Be Careful What You Wish For. United Dairy Industry of Michigan.

2. Dietary Guidelines Advisory Committee. (February 2015). Scientific Report of the 2105 Dietary Guidelines Advisory Committee. USDA and Department of Health and Human Services.

3. National Academy of Sciences. Institute of Medicine. Food and Nutrition Board. (2004). Dietary Reference Intakes for Water, Potassium, Sodium, Chloride, and Sulfate.

4. Genetics Home Reference. (May 2010). “Lactose Intolerance.” U.S. National Library of Medicine.

5. Michaëlsson, K., et al. (October 2014). Milk intake and risk of mortality and fractures in women and men: cohort studies. The British Medical Journal, 349.

6. Schmid, A and Walther, B. (July 2013). Natural Vitamin D Content in Animal Products. Advances in Nutrition, 4(453-462).

Sweet Sugar Coconut Fat | The Paleo Diet
If you’ve popped into your local Starbucks lately, you’ve already seen it. The Christmas red cups are here!  As someone who is admittedly an absolute Christmas fanatic, I must say that the hint of the season’s festivities in the air brings a smile to my face and that happy, and coaxes the warm holiday aura.

But one thing that doesn’t sit quite right is thinking about the sizeable number of syrupy sweet holiday drinks we’re consuming as a whole, let alone the sheer size of each individual drink has gone from 12 oz to 16 oz to… a 31 oz!1

A ‘Grande,’ 2% milk, peppermint latte is a whopping 54g of sugar from Starbucks.2 Thinking about supersizing to the mega 31 oz? That’s a whole heck of a lot of sugar (nearly double)!

But what if we want to enjoy a taste of the season? Is there a way to do so without wreaking havoc to our blood sugar, our mood, and our guts? Yes.

And it’s not about finding a ‘more Paleo’ sweetener. Instead of focusing on sweet, do yourself a favor and instead focus on fat. Without sugar, you can forget about the blood sugar spike, ensuing crash, and craving pangs for another.

Long before we ever knew about putting butter in coffee, in the lofty Himalayan mountains a few cups of yak butter tea, or po cha, was a welcome respite from the cold, thin air.[3] Since neither butter nor coffee are part of a strict Paleo diet, why not put a spin on the Tibetan model and brew a hot cup with a healthy, Paleo approved fat?

Can you say let’s go nuts with coconuts? Tasty, warming, and a with a fantastic creamy texture to boot, the Paleo recipe below will satisfy your palate and leave you feeling energized and ready to face the hectic holiday season… without ever feeling like you’ve had to deprive yourself!

Paleoista’s Holiday Coconut Tea

(Serves 2)

Ingredients

  • Herbal tea, your preference; try peppermint, cinnamon or ginger to create the holiday flavor profile
  • ¼ cup coconut butter, at room temperature
  • Ground cinnamon, to taste

Instructions

  1. Brew tea and let steep 3- 5 minutes.
  2. Remove tea leaves or bag and let cool slightly.
  3. Combine tea with coconut butter in blender and whiz to combine.
  4. Top with cinnamon and enjoy!

References

1. “Starbucks to Roll Out Biggest Drink Size Yet | Fox News.” Fox News. FOX News Network, 16 Jan. 2011. Web. 04 Nov. 2015.

2. “Peppermint Mocha.” Starbucks Coffee Company. Starbucks Coffee Company, n.d. Web. 04 Nov. 2015.

3. “Tea Tuesdays: Butter Up That Tea, Tibetan-Style.” NPR. NPR, n.d. Web. 04 Nov. 2015.

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