Tag Archives: vegetarian

Paleo Diet Vegetarian Diet Mediterranean Diet

As we spring into a new season, there has been renewed interest in how one diet stacks up to the next. In this presentation which I made at the Functional Medicine Conference in San Francisco in Spring of 2014, I contrasted the Paleo Diet to the Mediterranean Diet and vegan and vegetarian diets.

I have always said a Paleo Diet is not a diet per se, but rather a lifelong way of eating to reduce the risk of chronic disease. Although intuitively it seems like the traditional Mediterranean diet has been with us forever, on an evolutionary perspective (30 yrs per generation), this cultural dietary adaptation is relatively recent. Genetic studies of certain Mediterranean populations show that the majority, 65%, are not genetically evolved to digest lactose, the primary sugar in cows’ milk. Further, the Mediterranean diet is not as nutritionally (vitamins and minerals) dense as the Paleo Diet and it contains considerably more salt and is clearly not gluten free.

In our Three Part Series on Veganism and Vegetarianism, I have detailed extensively why this regime is an unnatural way of eating that has no evolutionary precedence in our species. No hunter gatherer society ever consumed a meatless diet, nor should you. So without further adieu, let’s take a closer look at how a Paleo Diet really stacks up to the Mediterranean and vegetarian diets.

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Cordially,

Loren Cordain, Ph.D., Professor Emeritus

Vegetarian Diet | The Paleo Diet

Did you miss Vegetarian and Vegan Diets: Nutritional Disasters Part 1 or Part 2?
Read Part 1 HERE
Read Part 2 HERE

Vegetarian Diets: Other Nutritional Shortcomings

You don’t have to look any further than the ADA’s Position Statement28 or the USDA’s recommendations on vegetarian diets142 to discover additional nutrient shortcomings caused by plant based diets. The ADA matter of factly mentions that “…key nutrients for vegetarians include protein, n-3 fatty acids, iron, zinc, iodine, calcium, and vitamins D and B12..28 The USDA notes that “…vegetarians may need to focus on…iron, calcium, zinc, and vitamin B12.142 These subtle admissions of potential nutrient deficiency problems associated with vegetarian diets represent the tip of a nutritional nightmare. Just as was the case with vegetarian diets and vitamin B12 deficiency, there is little credible scientific evidence to show that people eating a lifelong plant based diet (without taking supplements or eating fortified foods) can achieve adequate dietary intakes of omega 3 fatty acids (EPA and DHA), iron, zinc, iodine, calcium, and vitamin D. To this list you can also add vitamin B6 and taurine, an amino acid.

Mineral Deficiencies and Vegetarian Diets

One of the major complications with the assessment of dietary nutrient adequacy in vegetarian diets, or for that matter, any diet has to do with whether or not the vitamins and minerals measured in certain foods actually get absorbed into our bodies. The bioavailability of vitamins and minerals in foods is just as important in how they impact our health as is the simple content of these nutrients in a food. By now you know that phytate is not a good thing because it prevents absorption of essential minerals. Whole grains and legumes are rich sources of phytate. Accordingly, our bodies have great difficulty extracting certain minerals from these foods because they are tightly bound to phytate. Phytate in whole grains impairs calcium absorption and may adversely affect bone health. Further, phytate also binds zinc, thereby interfering with its assimilation and incorporation into our cells. To this list you can add iron and magnesium. Because vegetarian diets are virtually impossible to follow without including lots of whole grains, beans, soy and legumes, they are inherently high in phytate. This is why it is difficult or impossible for vegetarians and vegans to maintain adequate body stores of calcium, zinc and iron.

Zinc Deficiencies in Vegetarian Diets

From the discussion above, you know that zinc is crucial for normal male reproductive function, but it is also required for good health and disease resistance in virtually every cell in our bodies, whether you are a man, woman or child.20, 41 Marginal zinc status impairs our immune system, slows wound healing, adversely affects glucose and insulin metabolism, and damages our body’s built in antioxidant system.16, 55 Without adequate dietary zinc we experience more upper respiratory illnesses that last longer. Zinc lozenges can slow or prevent common cold symptoms, and zinc oxide creams applied topically can speed healing. If you have ever experienced painful cracked heels or nose bleeds that just wouldn’t stop, try rubbing zinc oxide ointments on these wounds – you will be amazed at how rapidly zinc can heal these stubborn sores. How we got into this problem (marginal zinc status or deficiencies) in the first place originates directly from our diets. Anybody eating excessive whole grains and/or legumes and not eating meat, fish or animal products on a regular basis45, 59, 62 puts themselves at risk for all illnesses and health problems associated with borderline or deficient zinc intakes.

Iron Deficiencies in Vegetarian Diets

Your body stores of iron run hand in hand with zinc. The same types of diets that produce zinc deficiencies also create iron deficiencies. High phytate vegetarian diets based upon whole grains, beans, soy and other legumes invariably cause iron deficiencies5, 135 which are the most common nutrient deficit worldwide. In the U.S. 9% of all women between 12 and 49 years are iron deficient, while 4% of 3 to 5 year old children have insufficient stores of this crucial mineral.25 If you are pregnant, low iron status increases your risk of dying during childbirth, and frequently causes low birth weights and preterm deliveries. Even more disturbing is the potential for iron deficiencies to prevent normal mental development in our children and young adults.39, 90, 96 As a parent, I would never wish upon my child or for that matter anyone else’s, a diet causing nutritional deficiencies known to impair brain development and normal mental function. But this is just the case if you eat a vegetarian diet and impose it upon your children. Plant based diets not only increase the risk of impaired cognitive function in your children, but will hamper your own mental functioning. Numerous experimental studies show that inadequate iron stores in adults can slow or impair tasks requiring concentration and mental clarity.73

One of the most important outcomes of diets that cause iron deficiencies is that they make us fatigued and tired. If you are an athlete or have a demanding job requiring physical exertion, low iron stores will invariably reduce your performance. A recent (2009) experiment involving 219 female soldiers during military training showed that iron supplements improved blood iron stores, increased performance for a 2 mile run and enhanced mood.92 Similarly a study by Dr. Hinton and colleagues demonstrated that iron supplements in iron deficient male and female athletes improved endurance performance and efficiency.56 Whether you are an athlete, a laborer or even an office worker, your best nutritional strategy to improve iron stores, add vigor to your life and improve performance is to eliminate whole grains and legumes from your diet by adopting The Paleo Diet.

The burden of proof that vegetarian diets will not produce multiple vitamin and mineral deficiencies lies upon the governmental (USDA) and dietary organizations (ADA) that recommend these diets to us all and tell us that they are safe.28, 142 You might expect that the experimental evidence surrounding vegetarian diet recommendations would be convincing and overpowering. Nothing could be further from the truth, particularly when it comes to iron deficiencies and vegetarian diets.

As always the devil is in the details when it comes to getting correct answers to nutritional questions. Scientists who believe that vegetarian diets don’t adversely affect our iron stores often cite scientific papers showing no difference between blood iron concentrations in vegetarians and meat eaters. What they don’t tell us is how iron measurements were performed in the experiments they quote to support their viewpoint. This information is absolutely essential in knowing if iron deficiencies exist or not. Any study examining blood levels of iron in vegetarians using either measurements of hemoglobin (an iron carrying substance in red blood cells) or hematocrit (the concentration of red blood cells) are unreliable indicators of long term iron status. A much better marker is an iron carrying molecule called ferritin.75 Virtually all epidemiological (population) studies of vegans or ovo/lacto vegetarians show them to be either deficient or borderline iron deficient when blood ferritin levels are measured. Given this nearly unanimous finding from epidemiological studies, you might think that either the USDA or the ADA would become concerned and re-examine their endorsement of vegetarian diets. Unfortunately, we still live with governmental and institutional dietary recommendations that may do considerable harm to our health.

The most convincing type of experiments to reveal whether or not vegetarian diets may cause our iron stores to nosedive are called dietary interventions. Why not put a large group of non-vegetarians on a plant based diet for an extended period and see what happens to their blood iron levels? Wow what a great idea – unfortunately no such study has ever been conducted. The closest we have come to this experiment is a short term study (8 weeks) by Dr. Janet Hunt and co-workers at the Grand Forks Human Nutrition Research Center in North Dakota.63 The results of this experiment were anything but conclusive as the researchers made a fundamental blunder in the design of their experiment – they forgot to include a control group. Without a control group, it is impossible to interpret the outcome of this or any experiment.

Nevertheless, when women were placed on lacto/ovo vegetarian diets, their intestinal iron absorption was reduced by 70%; however, inexplicably, blood ferritin levels (a marker of their long-term iron status) did not decline for the group as a whole. It should be noted that nearly half of the subjects did experience drops in blood ferritin concentrations. Because the authors of this study failed to include a control group, then extraneous variables likely swayed the experiment’s outcome. You recall from earlier in this essay that vegetarian diets caused 7 out of 9 women to stop ovulating. With the cessation of menstrual periods, monthly blood loses also cease which in turn prevents monthly iron losses because blood is a rich source of iron. Hence, in any study evaluating blood iron stores in women, it is absolutely essential to know if their normal menstrual cycles were altered. Unfortunately, Dr. Hunt did not provide us with this information, thereby making the correct interpretation of her experiment difficult or impossible.

In order to once and for all know whether or not vegetarian diets cause iron deficiencies, we would need to perform Dr. Hunt’s experiment again, for at least a year with more subjects, a control group and monitor changes in menstrual periods. You would think that this kind of very basic experimental evidence would have already been in place before any governmental or institutional organization told us that vegetarian diets were safe and didn’t cause nutritional deficiencies. Unfortunately, these precautionary steps have never been taken, and millions of Americans who adhere to vegetarian diets with the mistaken belief that they will benefit health-wise will actually suffer.

Iodine Deficiencies in Vegetarian Diets

A number of studies have reported that vegetarian and vegan diets increase the risk for iodine deficiency.40, 77, 102, 153 One study from Europe demonstrated that 80% of vegans and 25% of ovo/lacto vegetarians suffered from iodine deficiency.77 Additionally, a dietary intervention by Dr. Remer and colleagues in 1999 confirmed this epidemiological evidence.102 After only five days on ovo/lacto vegetarian diets, iodine status and function became impaired in healthy adults.102 The primary reason why vegetarian diets cause iodine deficiencies is that plant foods (except for seaweed) are generally poor sources of iodine compared to meat, eggs, poultry and fish. Gross deficiencies of iodine cause our thyroid glands to swell producing a condition known as goiter, and in pregnant women result in severe birth defects called cretinism.141 Because salt is fortified with iodine, most people in the U.S. and Europe rarely develop gross iodine deficiencies.40, 140, 141 However moderate to mild iodine deficiencies appear in westernized countries, particularly among vegetarians and vegans.77, 102 Moderate iodine deficiency impairs normal growth in children and adversely affects mental development.140, 141, 152 A large meta analysis revealed that moderate childhood iodine deficiency lowered I.Q. by 12-13.5 points.153 Paleo Diets are not just good medicine for adults, but they also ensure normal physical and mental development in our children because of their high iodine content.

One of the problems with plant based diets is that they may put into play a vicious cycle that makes iodine deficiencies worse. When the thyroid glands iodine stores become depleted, as often happens with vegetarian diets, then certain antinutrients found in plant foods can gain a foot hold and further aggravate iodine shortages. Soy beans and soy products are frequently a mainstay in vegetarian diets and may promote inflammation.66 Unfortunately soy contains certain antinutrients (isoflavones) that impair iodine metabolism in the thyroid gland,43, 95 but only when our body stores of iodine are already depleted. Other plant foods (millet, cassava root, lima beans, sweet potatoes, and cruciferous vegetables [broccoli, cauliflower, turnips, kale, cabbage]) also contain a variety of antinutrients which hinder normal iodine metabolism. So, plant based diets put us at risk for developing iodine deficiencies in the first place, and when this happens our bodies become vulnerable to plant antinutrients that worsen the pre-existing deficiency. The important point here is that antinutritional compounds have virtually zero effect upon our thyroid gland when our body stores of iodine are normal and fully replete. Because meats, fish, eggs and poultry are rich sources of iodine, you will never have to worry about this nutrient when you eat Paleo style.

Vitamin D and Vitamin B6 Deficiencies in Vegetarian Diets

In my paper, Cereal Grains: Humanity’s Double Edged Sword, I have pointed out how excessive consumption of whole grains adversely affects vitamin D status in our bodies.148 Hence it goes without saying that vitamin D deficiencies run rampant in vegetarians worldwide because it is nearly impossible to become a full-fledged vegetarian without eating lots of grains. In the largest study of vegetarians ever undertaken (The Epic-Oxford Study), Dr. Crowe and fellow researchers reported that blood concentrations of vitamin D were highest in meat eaters and lowest in vegans and vegetarians.29 Nearly 8% of the vegans maintained clinical deficiencies of vitamin D. Vitamin D is not really a vitamin at all, but rather a crucial hormone that impacts virtually every cell in our bodies.

By now, you are starting to get a pretty good picture of what a nutritional nightmare vegetarian diets really are. When we let the data speak for itself, the number of nutrient deficiencies and adverse health effects associated with plant based diets are appalling and far outweigh any supposed health effects of this unnatural way of eating. One of the biggest kept secrets about vegan or vegetarian diets is that they frequently cause vitamin B6 deficiencies. If you recall, neither the ADA,28 nor the USDA142 has given us any warning that meatless diets increase our risk for vitamin B6 deficiencies.

On paper, it would appear that vegetarian diets generally meet daily recommended intakes for vitamin B6. This assumption comes primarily from population surveys examining the foods that vegans and vegetarians normally eat. In contrast, when blood samples are analyzed from people relying upon plant based diets, they unexpectedly reveal that long term vegetarians and vegans frequently are deficient vitamin B6. A recent study of 93 German vegans by Dr. Waldman and colleagues showed that 58% of these men and women suffered from vitamin B6 deficiencies despite seemingly adequate intakes of this essential nutrient.131 It turns out that the type of vitamin B-6 (pyridoxine glucoside) found in plant foods is poorly absorbed.47, 103 The presence of pyridoxine glucoside in plant foods along with fiber has been reported to reduce the bioavailability of vitamin B6 so that only 20 to 25% is absorbed and completely utilized.47 In contrast, vitamin B6 found in animal foods is easily assimilated, and an estimated 75 to 100% fully makes its way into our bloodstreams.47

Compelling evidence that vegetarian diets relying upon the plant form of vitamin B6 adversely affect our body’s overall vitamin B6 stores comes from Dr. Leklem’s laboratory at Oregon State University.47 Nine women were put on diets either high or low in the plant form of vitamin B6 (pyridoxine glucoside). After only 18 days, the high pyridoxine glucoside diets consistently lowered blood concentrations and other indices of vitamin B6 status. Deficiencies in this vitamin elevate blood homocysteine concentrations and increase our risk for cardiovascular disease similar to shortages of folate and vitamin B12. Further, vitamin B6 is an important factor in normal immune system functioning149 and shortfalls of this crucial nutrient have been identified in depression150 and colorectal cancer.151

Omega 3 Fatty Acid Deficiencies in Vegetarian Diets

A few years ago I was involved in a series of experiments here at Colorado State University in which we were interested in determining how high and low salt diets affected exercise-induced asthma. Our working hypothesis was that high salt diets would make measures of lung function worse, and low salt diets would improve things. One of our concerns with this experiment was to somehow make sure our subjects had fully complied with either the high or low salt diets. Completely removing salt from your diet is not an easy thing to do, and if some of our subjects had decided to sneak in a piece of pizza or some Doritos, it would mess up the experiment’s outcome. Fortunately, there was an easy way to figure out if our subjects had been compliant with the prescribed diets. All we had to do was to spot check their urine, because measurement of urinary salt levels is an accurate gauge of dietary salt consumption. High urinary salt levels universally reflect high salt consumption, whereas low urinary salt concentrations indicate low salt consumption. Short of major disease, there is virtually no other way high amounts of salt in the urine don’t indicate high amounts of salt in the diet.

In a similar manner, there are equivalent telltale indicators of omega 3 fatty acids in our bloodstreams that tell us beyond a shadow of a doubt whether or not we have regularly consumed fish, seafood or other good sources these healthful fats. The three main types of omega 3 fatty acids we need to concern ourselves with are EPA, DHA and ALA. EPA and DHA are called long chain omega 3 fatty acids and are only found in high amounts in fish, seafood, certain meats, and other foods of animal origin. Plant foods contain no EPA or DHA. On the other hand, ALA is called a short chain fatty acid and is found in both plant and animal foods. Both EPA and DHA in our red blood cells are markers of these important fatty acids in our diet. Without good dietary sources of EPA and DHA such as are found in fish, seafood and certain meats, our blood levels of EPA and DHA will decline. Just like salt in our urine was an indicator for dietary salt, EPA and DHA concentrations in our red blood cells are markers for our dietary intake of these long chain omega 3 fatty acids. It is virtually impossible to achieve high blood levels of EPA and DHA without regularly consuming fish, seafood and certain meats and organ meats (particularly grass produced meats and organ meats).

One of the major nutritional shortcomings in vegans is that they obtain absolutely no EPA or DHA from their diets.108, 110, 111 Consequently, they are totally dependent upon plant based ALA, supplements or fortified foods to obtain these healthful long chain omega 3 fatty acids. Without supplements or fortified foods, all vegans will become deficient in EPA and DHA because plant based ALA is inefficiently converted into these long chain fatty acids in our bodies. The liver converts less than 5% of ALA into EPA and less than 1% of ALA into DHA.15, 97 Virtually every epidemiological study that has ever been published shows that vegans, who do not supplement or consume long chain omega 3 fortified foods, to be deficient in both EPA and DHA76, 88, 108, 110, 111 Lacto/ovo vegetarians don’t fare much better because milk and egg based vegetarian diets simply do not supply sufficient DHA or EPA to maintain normal blood concentrations.88, 111

There is little doubt that vegan or vegetarian diets cause reductions in blood concentrations of DHA and EPA, which in turn represent a potent risk factor for many chronic diseases. Perhaps the single most important dietary recommendation to improve your health and prevent illness is to increase your dietary intake of EPA and DHA. Thousands of scientific papers covering an assortment of diseases clearly show the health benefits of these fatty acids. In randomized clinical trials in patients with pre-existing heart disease, omega-3 fatty acid supplements significantly reduced cardiovascular events (deaths, non-fatal heart attacks, and non-fatal strokes).19, 48, 138 Omega-3 fatty acids lessen the risk for heart disease through a number of means including a reduction in heart beat irregularities called arrhythmias, a decrease in blood clots, and reduced inflammation which is now known to be an chief factor causing atherosclerosis or artery clogging.

In addition to lowering the risk for heart disease, regular consumption of fish or supplemental omega-3 fatty acids may be useful in averting, treating, or improving a wide range of diseases and disorders, including virtually all inflammatory diseases (any disease ending with “itis”): rheumatoid arthritis,99 inflammatory bowel disorders (Crohn’s disease, ulcerative colitis), periodontal disease (gingivitis). Also mental disorders (autism, depression),3, 84 postpartum depression, bi-polar disorder, borderline personality disorder, impaired cognitive development in infants and children) may respond favorably to these beneficial fatty acids. Further, acne, asthma, exercise induced asthma, many types of cancers,120 macular degeneration, pre-term birth, psoriasis, insulin resistance, type 2 diabetes, cancer cachexia, intermittent claudication, skin damage from sunlight, IgA nephropathy, lupus erythematosus, type 1 diabetes, multiple sclerosis, and migraine headaches also improve with omega 3 fatty acids.

Taurine deficiencies in Vegetarian Diets

Although the number of nutrients which are frequently lacking in vegetarian and vegan diets may seem endless to you, we are now at the end of the list. Taurine is an amino acid (actually a sulfonic acid because it lacks a carboxyl group) in our bloodstreams that has multiple functions in every cell of our body. Unfortunately, this nutrient is not present in any plant food and is found in low concentrations in milk (6 mg per cup).80 In contrast, all flesh foods are excellent sources of taurine.80 For example, ¼ pound of dark meat from chicken provides 200mg of taurine. Shellfish are even richer still with over 800mg per quarter pound. The daily taurine intake in non-vegetarians is about 150mg, whereas lacto/ovo vegetarians take in about 17mg per day, and vegans get none. Although our livers can manufacture taurine from precursor molecules, our capacity to do so is limited – so much so that this amino acid is regularly fortified in infant formulas. As you might expect, studies of vegans show that their blood taurine levels are lower than meat eaters.81, 100 How depleted blood concentrations of taurine affect our overall health, is not entirely understood. Nevertheless, shortages of this amino acid and omega 3 fatty acids (EPA and DHA) may cause certain elements (platelets) in our blood to clot more rapidly which in turn increase our risk for cardiovascular disease.85, 91 Despite their meat free diets, vegetarians almost always exhibit abnormal platelets that excessively adhere to one another. In one dietary intervention, Dr. Mezzano and colleagues demonstrated that after eight weeks of EPA and DHA supplementation normal platelet function was restored in a group of 18 lacto/ovo vegetarians.85 Obviously, compromised taurine status will never become a problem in Paleo Diets, because meat, fish, poultry and animal products are consumed at nearly every meal.

In summary, if you have adopted, or are considering adopting a plant based diet for reasons of improving your health, make sure you reread this chapter and look up all of the references I have provided you. The evidence that vegetarian and vegan diets almost always cause a multitude of nutritional deficiencies is overwhelming and conclusive. Over the course of a lifetime, vegetarian diets will not reduce your risk of chronic disease and will not allow you to live longer. Rather, this abnormal way of eating will predispose you to a host of health problems and illnesses. Vegetarianism is an unnatural way of eating that has no evolutionary precedence in our species. No hunter-gatherer society ever consumed a meatless diet, nor should you. The ADA has labeled The Paleo Diet a fad diet because it eliminates “two entire food groups” (grains and dairy). Yet hypocritically, they exempt vegan diets from this characterization despite also eliminating two food groups (dairy, meats and fish). If The Paleo Diet is a fad diet, then it is the world’s oldest.

Cordially,

Loren Cordain, Ph.D., Professor Emeritus

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Vegetarian Diet | The Paleo Diet

Did you miss Vegetarian and Vegan Diets: Nutritional Disasters Part 1? Read it HERE

Vegetarian Diets and Homocysteine

Vitamin B12 deficiencies caused by vegetarian or vegan diets are just as devastating to adults as they are to infants and pregnant women. Vitamins technically are defined as “organic catalysts” – meaning that without their presence in our diets, our metabolic machinery slows, or is sufficiently damaged to eventually cause illness and disease. One of the most destructive changes in our bodies caused by vitamin B12 deficiency is the appearance of a toxic substance in our bloodstream known as homocysteine. Without sufficient dietary sources of vitamin B12, a chemical reaction within our bodies is impaired and causes blood concentrations of homocysteine to rise. Homocysteine is a toxin for almost every cell in our bodies, and increases the risk for birth defects, infertility, dementia, psychological illness, stroke, heart attacks, blood vessel disease, blood clots, osteoporosis and overall death rates. Worldwide studies of vegetarians and vegans show that the less animal food they eat, the higher are their blood concentrations of homocysteine.9, 21, 38, 60, 67, 70, 94, 101 Let’s take a look at how vegetarian diets raise blood concentrations of homocysteine and increase the risk for numerous diseases.

Homocysteine and Cardiovascular Disease

It is widely assumed that vegetarian diets reduce the risk for cardiovascular disease and heart attacks because they lower total and saturated fats in our diets. Unfortunately, this simplistic explanation is only part of the story. Total fat and saturated fat have been shown in large meta analyses to have negligible effect upon the atherosclerotic process that clogs the arteries and causes heart and blood vessel disease.143-146 In contrast, meta analyses published in the past 15 years have confirmed that homocysteine is an independent risk factor for cardiovascular disease and heart attacks.61, 130 The higher your blood levels of homocysteine, the greater will be your risk of having a stroke or heart attack. As I mentioned earlier, homocysteine is toxic to almost all cells in our bodies. It is particularly dangerous when high concentrations build up in our bloodstreams because it damages the cells lining blood vessels. This initial injury to the blood vessels represents one of the first steps in the artery clogging process. If blood concentrations of homocysteine remain high and the blood vessel damage goes on unabated for decades, it may result in fatal strokes and heart attacks. A recent (2008) meta analysis by Dr. Humphrey and colleagues indicated that for each (5 micromol/L) increase in blood homocysteine levels, the risk for cardiovascular disease events increased by approximately 20%.61

Because vegetarian diets cause vitamin B12 levels in the bloodstream to plummet, which in turn causes homocysteine levels to dangerously rise, you might expect to find high rates of cardiovascular disease in strict lifelong vegetarians. One of the problems in examining cardiovascular disease in vegetarians from the U.S. and Europe is that many of them aren’t strict vegetarians, and typically haven’t consumed vegetarian diets for their entire lives. All of these variables tend to confound the results of epidemiological studies. Given this scenario, what better place to examine vegetarian diets and cardiovascular disease than in India? With a population of 1.17 billion people, 31 % (362,700,000) of whom are vegetarians,42 India represents a country which can give us insight into study cardiovascular disease and plant based diets. As opposed to vegetarians in the U.S. and Europe, many Indian vegetarians are committed to lifelong vegetarian diets due to their religious convictions and family conventions.

If vegetarian diets provide protection from cardiovascular disease as the ADA suggests, then you might expect to find a low prevalence of heart disease and stroke in India because almost one third of its population are vegetarians. Unfortunately, this is not the case.137 In reality, the incidence of cardiovascular disease is much higher in India than in most other places in the world. Moreover, Indians develop cardiovascular disease at a much earlier age than people from other countries. In the largest study ever of 368 lifelong Indian vegetarians with cardiovascular disease, Dr. Kumar and co-workers showed that heart disease was higher in vegetarians and that they had lower blood levels of vitamin B12.79 I quote Dr. Kumar, “We believe that the beneficial effect of a vegetarian diet in this population is circumvented by deficiency of vitamin B12.

Homocysteine and Neurological Diseases

Not only is homocysteine toxic to our blood vessels, but numerous studies also have found that it adversely affects brain function, behavior and mood.23, 129 People with higher blood concentrations of homocysteine have a greater risk for Alzheimer’s disease, dementia, depression, Parkinson’s disease and stroke. In a comprehensive 2010 review of 1,627 articles on high blood levels of homocysteine and vitamin B12 Dr. Werder133 concluded that: “Hyperhomocysteinemia (high blood levels of homocysteine) with or without hypovitaminosis B12 (low blood levels of vitamin B12) is a risk factor for dementia.” In addition to vitamin B12 deficiencies another B vitamin, folate, can cause blood concentrations of homocysteine to rise. However in a study involving 2,403 older people, Dr. Clarke and colleagues24 found that, “the relative importance of vitamin B12 deficiency as a determinant of homocysteine concentrations and cognitive impairment is probably greater than that of folate deficiency in older adults.” Additionally, a recent study by Dr. Selhub’s research group showed that high dietary intakes of folate seems to make B12 deficiencies worse by further increasing blood concentrations of homocysteine.114 This is precisely the dietary pattern found in the blood of most vegetarians – low B12 and adequate or elevated folate. Is it any wonder why so many vegetarians and vegans have dangerously high blood levels of homocysteine?

Homocysteine and Bone Disease

The list of chronic diseases associated with high blood concentrations of homocysteine seems almost endless and has recently been extended to bone disease. By raising blood homocysteine levels, vegetarian diets may not only increase your risk for neurological disorders and cardiovascular disease, but they also increase bone fracture risk. The notion that vegetarians have weaker bones than their meat eating counterparts was verified in the largest study ever undertaken in a vegetarian population (9,420 vegetarians and 1,126 vegans). The authors of the EPIC-Oxford study concluded that, “The higher fracture risk in the vegans appeared to be a consequence of their considerably lower mean calcium intake.2 Low calcium and vitamin D intakes are well known risk factors for bone fractures and osteoporosis, and these nutritional deficiencies are common in vegan and vegetarian populations. But to add insult to injury, you can now add another strike against vegan and vegetarian diets in promoting bone disease. Since 2003, numerous studies have identified low B12, low folate or high homocysteine blood levels as risk factors for poor bone density, increased fractures, or osteoporosis.2, 4, 17, 34, 51, 53, 54, 58, 78, 82, 112, 125

Although we don’t completely understand how high blood levels of homocysteine adversely affect bone, tissue studies have identified a number of mechanisms. First homocysteine seems to impair the normal bone mineralization process.17 It also causes an accelerated breakdown of bone and inhibits the formation of new bone cells.51 Some of the best evidence implicating homocysteine in bone disease comes from human dietary interventions. In a two year study of 559 elderly women in Japan, Dr. Sato and fellow researchers showed that supplementation of vitamin B12 and folate reduced blood concentrations of homocysteine by 38%.112 But more importantly women in the vitamin supplemented group suffered 33 fewer hip fractures than women in the un-supplemented control group.

One of the best ways you can prevent hip fractures is to follow The Paleo Diet. Because you will be eating meat and fish at virtually every meal, you won’t have to worry about vitamin B12 deficiencies, as these two foods are our best sources of this essential vitamin. The other mainstay of The Paleo Diet is fresh fruit and veggies which are rich sources of the B vitamin, folate. The combination of lots of meat and fish along with plenty of fruits and vegetables at every meal will ensure that you do not develop vitamin B12 or folate deficiencies and that your blood homocysteine levels will remain low throughout your life – just as nature intended.

Homocysteine and Infertility

Before I leave homocysteine, I’ve got to cover one more topic that for some of you may be the most important revelation of all about this noxious molecule. By now, you know that elevated blood concentrations of homocysteine result primarily from too little vitamin B12 and folate in our diets. When adequate stores of these two B vitamins are present from nutritious foods in our diet (e.g. meats, fresh fruits and veggies), then our cells can defuse the poisonous effects of homocysteine and convert it into less toxic compounds. However, when B12 is lacking or deficient, as it almost always is in vegetarian and vegan diets, then homocysteine builds up in our bloodstream and literally infiltrates nearly every cell in our bodies.

Healthy egg cells in women and healthy sperm cells in men are absolutely essential requirements for getting pregnant, staying pregnant and producing normal embryos, vigorous infants and healthy children. I’ve previously outlined how vitamin B12 deficiencies can elevate blood levels of homocysteine and cause numerous adverse health problems in pregnant women, their unborn fetuses and nursing infants. In addition to these unfavorable effects, a diet deficient or marginal in vitamins B12 and folate can severely reduce your chances for successful fertilization and conception. Infertility is a huge problem in both the U.S. and elsewhere11, 122 and affects at least 6 million people in the U.S. or more importantly about 7.4% of the reproductive age population.119 Many environmental and genetic factors may be involved. However, one thing is certain, as a couple, if you or your partner’s blood levels of vitamin B12 and/or folate are low and your homocysteine is elevated, your chances for a normal conception and pregnancy will be significantly reduced.8, 12-14, 30, 36, 93, 98, 116, 128

The injurious effects of homocysteine in our bones and in our cardiovascular and nervous systems have been much better studied than in our reproductive systems. Nevertheless, it is becoming increasingly evident that the low vitamin B12 and folate status responsible for elevated homocysteine is toxic to both sperm and egg cells and may represent a major, previously unrecognized risk factor for infertility. More than 30 years ago, at least one group of researchers pointed out that Indian vegetarian men maintained lower vitamin B12 concentrations in their sperm than non-vegetarians and attributed these values to their vegetarian diet.65 Additionally, a number of these earlier studies hinted that vitamin B12 supplementation could improve sperm function and vigor and even boost male fertility.57, 65

If we fast forward to the 21st century, in the past five to ten years similar nutritional patterns have been discovered in western populations. In a recent (2009) study of 172 men and 223 women who were unable to conceive, 36% of men and 23% of women had vitamin B12 deficiencies. Almost 40% of the infertile men had abnormal semen that was directly related to their vitamin B12 deficiencies. Other recent studies in men show that low dietary folate and vitamin B12 are associated with high blood concentrations of homocysteine that likely underlie abnormal sperm function. On the flip side of the equation, women with compromised dietary B12 and folate intakes frequently have elevated blood levels of homocysteine68 which prevent them from becoming pregnant. We are not completely sure how these blood chemistry changes impede successful pregnancies in women, but tissue studies suggest that egg cells infiltrated by homocysteine and deficient in vitamin B12 and folate make them fragile and unable to continue with a normal pregnancy once fertilized.13, 126

Vegetarian Diets: Additional Fertility Problems

Menstrual Problems caused by Vegetarian Diets

In addition to B vitamin deficiencies and elevated blood concentrations of homocysteine, vegetarian diets are frequently associated with menstrual problems known to affect fertility. A total of five studies have compared the incidence of menstrual irregularities between vegetarians and meat eaters. Four out of these five studies demonstrated significantly higher rates of menstrual complications in vegetarians. Not all types of scientific experiments have equal clout in establishing cause and effect. Of the five studies, four were epidemiological (population) studies and one was an actual experimental intervention. Because dietary interventions represent the most powerful experimental procedure for determining if dietary changes improve health or cause illness, they carry more weight than epidemiological studies. Let’s take a look at the only dietary intervention investigating vegetarian diets on menstrual health.

Dr. Pirke and researchers at the University of Trier in Germany randomly divided 18 young women with normal menstrual periods into either vegetarian or non-vegetarian diet groups. After six weeks, 7 of the 9 women assigned to the vegetarian diet stopped ovulating, whereas only a single woman in the meat eating group experienced this problem.147 The results of this experiment are shocking. Within only six weeks of consuming a vegetarian diet, 78% of healthy, normally cycling women ceased ovulating. The takeaway: if you are trying to get pregnant, one of your best strategies is to avoid vegetarian diets. While you’re at it, make sure your husband or partner does the same.

Zinc Deficiencies Impair Sperm Function

One of the most frequent nutritional shortcomings of vegetarian and vegan diets is that they fall short of recommended intakes for zinc. In the largest epidemiological study ever of vegetarians (The EPIC-Oxford Study) Dr. Davey and colleagues noted that vegans had “…the lowest intakes of retinol [vitamin A], vitamin B12, vitamin D, calcium and zinc” when compared to meat and fish eaters.31 More importantly, with zinc it’s not just how much is present in your food, but how much is actually absorbed in your body. Although dietary zinc intakes in vegetarian diets sometimes appear to be adequate on paper – in the body they actually result in deficiencies32, 44, 45, 62 because most of plant based zinc is bound to phytate and, therefore, unavailable for absorption. Phytate is an antinutrient found in whole grains, beans, soy and other legumes that prevents normal assimilation of many minerals. Laboratory experiments show that vegetarians only absorb about half as much zinc as meat eaters because zinc from animal food is much better assimilated than from plant foods.

Based upon this information, you might expect blood concentrations of zinc to be lower in vegetarians than meat eaters. Sometimes scientists have found this to be the case, but not always. The problem here has to do with where zinc ends up in our bodies after we ingest it. Most zinc finds its way into the interior of cells and does not accumulate in the liquid portion (plasma) of blood. Consequently, unless scientists examine zinc concentrations within cells, readings obtained in blood plasma frequently do not accurately reflect body stores of this essential mineral. In virtually every study of vegetarians which measured zinc levels inside various cells (red blood cells, hair cells and skin cells in saliva), plant based diets caused zinc deficiencies. In one study, 12 meat eating women were put on a lacto-ovo vegetarian diet, and after only 22 days Dr. Freeland-Graves and co-workers reported that zinc concentrations in the women’s salivary cells plunged by 27%.44 Similar results were described by Dr. Srikumar and colleagues from a longer term experiment in which 20 meat eating men and women adopted a lactovegetarian diet for an entire year.117 In this study, both hair cells and blood levels of zinc sharply declined and remained low throughout the 12 month experiment.

So, I’ve set the stage for zinc deficiencies and infertility problems. Because of their low zinc content and bioavailability, long term vegetarian diets almost always cause zinc deficiencies.20, 32, 44, 45, 62 Numerous studies have shown that infertile/subfertile men had poor seminal quality that was associated with vegetarian diets6, 65 or reduced zinc levels in their semen. Virtually every well controlled experimental study ever conducted shows that men put on zinc deficient diets ended up with reduced sperm counts, impaired sperm health and often depressed blood testosterone levels. The good news is that these deleterious changes in male reproductive function can be reversed if zinc rich diets (e.g. The Paleo Diet) are consumed, or if zinc pills are supplemented.136 Dr. Steegers-Theunissen’s research group in the Netherlands showed dramatic improvements in the reproductive health of 103 sub-fertile men when zinc and folic acid were supplemented.37 Following the six month supplementation program, sperm counts increased significantly in the sub-fertile men while sperm abnormalities declined by 4%. A similar study of 14 infertile men from India also indicated that zinc supplementation increased sperm health, sperm counts and shortly thereafter resulted in three successful conceptions by these men’s wives.123

Whether you are a man or woman, if you want to sidestep infertility problems, the best advice I can give you is to abandon vegetarian diets and adopt the nutritional patterns that have sustained our hunter gatherer ancestors for the past 2.6 million years. There are no known risks to adopting The Paleo Diet, and in fact, regular consumption of meat, seafood and fresh fruit and vegetables at the expense of cereals, dairy and processed foods will prevent vitamin B12 and folate deficiencies. In turn these essential vitamins will ensure that your blood levels of homocysteine will return to normal – effectively reducing your risk for cardiovascular, neurological, bone and reproductive diseases.

In Vegetarian and Vegan Diets: Nutritional Disasters Part 3 we’ll discuss the additional copious shortcomings of vegetarian and vegan diets and why The Paleo Diet is optimal for health and wellbeing.

Cordially,

Loren Cordain, Ph.D., Professor Emeritus

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120. Szymanski KM, Wheeler DC, Mucci LA. Fish consumption and prostate cancer risk: a review and meta-analysis. Am J Clin Nutr. 2010 Nov;92(5):1223-33.

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Vegetarian Diet | The Paleo Diet

Over the years since the publication of my first book, I have been asked time and again if there is a vegetarian version of The Paleo Diet. I’ve got to say emphatically – No! Vegetarian diets are a bit of a moving target because they come in at least three major versions. We all know in principle that vegetarians do not eat meat, poultry or fish – this is the first and foremost characteristic of vegetarian diets. Less restrictive are lacto/ovo vegetarians who limit their animal food choices to dairy products and/or eggs, whereas vegans eat plant foods exclusively. A recent study published by Vegetarian Times Magazine revealed that 3.2% of U.S. adults or 7.3 million people follow a vegetarian-based diet.127 Approximately 0.5% or 1 million Americans are vegans. The study also indicated that over half (53%) of current vegetarians ate their plant based diet to improve overall health. Additional reasons underlying their vegetarian lifestyles were: 1) animal welfare cited by 54%, 2) environmental concerns named by 47%, 3) natural approaches to wellness mentioned by 39%, 4) food safety issues brought up by 31% and 5) weight loss and weight maintenance issues were cited by 25% of the respondents.127

First, let me say I respect everyone’s choice to eat whatever diet they like and those foods that they feel are best suited for themselves and their families. I also respect people’s decisions to abstain from eating meat for religious, moral, and ethical reasons. Nevertheless, as a scientist, I hope that we all try to make dietary decisions based not just upon philosophical and ethical issues, but also upon foods that are good for our bodies and long term health. Accordingly, I simply can’t lend my support to any version of vegetarian diets that people may adopt for the mistaken idea that these diets “improve overall health.”

Vegetarian Diets: The Evolutionary Evidence

Animal Food Subsistence | The Paleo DietAlthough vegetarianism has deep historical roots dating back at least to 500 BC with such ancient Greeks as Pythagoras, Porphyry and Plutarch,106, 115, 134 this manner of eating has only been with us for the mere blink of an eye on an evolutionary timescale. In our comprehensive analysis of 229 hunter-gatherer diets, my research group and I showed beyond question that no historically studied foragers were vegetarians.26 In fact, whenever and wherever animal foods were available they were always preferred over plant foods.26 The chart to the left shows the overwhelming preference for animal foods in all 229 hunter-gatherer societies that we studied. Notice that not a single foraging society fell into the (0 – 5%) animal subsistence category.

Most (73%) of the 229 hunter-gatherers consumed 46% or more of their daily energy as animal food.26 The compelling reason for their preference of animal foods over plant foods was because hunter-gatherers got more bang (food calories) for the buck (their energy expended to obtain the food), as verified by optimal foraging theory.

Human preference and appetite for meat, marrow and animal food has an incredibly long history in our ancestral line.18, 33 Fossils of butchered animals with stone tool-cut marks on their bones were discovered in Africa dating back 2.5 million years.33 These definitive “smoking guns” in the archaeological record leave little doubt that all human species ate animal foods from the very get-go of our existence. Scientists are able to determine the relative percentage of plant and animal food in extinct human (hominid) species by analyzing elements called isotopes within their fossilized bones.10, 104, 105 Every single hominid skeleton examined since the emergence of our own genus (Homo) 2.5 million years ago show an isotopic signature characteristic of meat based diets.10, 83, 104, 105, 124 Further, if we compare our biochemical and anatomical machinery to cats, who are absolute carnivores, we both share evolutionary enzyme pathways characteristic of processing lots of meat.27 If you are interested in these details, I have written about them in my debate with the noted vegetarian, Dr. T. Colin Campbell, author of The China Study.27Download the Full Debate Here

If we accept the idea that vegetarianism represents an ideal human diet, then this manner of eating must be part of a much larger or ultimate mechanism governing human biology. What I’m getting at is the question of “Why?” Why would a vegetarian diet, or for that matter, any diet represent an optimal nutritional road map for our species? Any unified theory of human nutrition is a detective story in which scientists attempt to reveal or uncover biological systems that have been designed by, and put into place by evolution through natural selection. Accordingly, hypotheses regarding what we should and shouldn’t eat must be consistent with the system and ancient environments that engineered our current genes. If we are to buy into vegetarianism, then the system, evolution via natural selection, which shaped our present genome necessarily had to be conditioned over eons by a plant based, vegetarian diet. Otherwise, there is no rationale alternative hypothesis to explain why humans would “prosper and thrive” on vegetarian diets.

As I have extensively pointed out,26, 27 there is no credible fossil, archeological, anthropological or biochemical evidence to show that any hunter-gatherers or pre-agricultural humans ever consumed all plant based diets. This information should be your first clue that there just may be some problems with vegetarian dietary recommendations created by humans for humans. What is that expression? “We are all human, we all make mistakes.” Let us not depend upon human frailties for dietary advice, but rather let us fall back on the wisdom of the system, again, evolution via natural selection, that designed the diet to which we are genetically adapted.

Vegetarian Diets: The Experimental Evidence

If you are considering adopting a vegetarian diet because you think it may improve your overall health and wellbeing, my immediate advice to you would be to forget it. I urge you to always let the data speak for itself, and don’t listen to me or anyone else until you have carefully scrutinized both sides of this or any other nutritional argument. I can guarantee you that the assessment of positive health effects, or lack thereof, caused by vegetarian diets is not just a straight forward matter involving objectivity and a mere sifting of scientific facts. Rather, this inquiry is politically charged involving charismatic individuals and well known scientists promoting a vegetarian viewpoint that is frequently at odds with the best science.

If you are currently a vegetarian or vegan, one of the most powerful health expectations for adopting this lifestyle is that you will outlive your “hamburger eating” neighbors by escaping cancer, 72 heart disease,69, 71 and all other causes of death (mortality).69, 71 In fact, if truth be told, your lifelong dietary deprivations will not prolong your lifespan, but rather will produce multiple nutrient deficiencies that are associated with numerous health problems and illnesses. If you have forced plant based diets upon your children, or unborn fetus they will also suffer. Not a pretty picture. Now let’s let the data speak for itself and get into the science of vegetarian diets and health.

In their 2009 Position Statement on Vegetarian Diets,28 The American Dietetic Association tells us,”…appropriately planned vegetarian diets, including total vegetarian or vegan diets are healthful, nutritionally adequate, and may provide health benefits in the prevention and treatment of certain disease. Well-planned vegetarian diets are appropriate for individuals during all stages of the life cycle, including pregnancy, lactation, infancy, childhood, and adolescence, and for athletes.” I don’t know what planet the authors of this paper came from or what scientific journals they have been reading, but these statements simply are not supported by the data.

To start with, if vegetarian diets are so healthful, then any reasonable person might expect that people eating plant based diets would have lower death rates from all causes than their meat eating counterparts. This question was never fully answered until 1999 when Dr. Key and colleagues at Oxford University conducted a large meta analysis comparing overall death rates between 27,808 vegetarians and 48,364 meat eaters.69 I quote Dr. Key’s study, “There were no significant differences between vegetarians and non-vegetarians in mortality from cerebrovascular disease, stomach cancer, colorectal cancer, lung cancer, breast cancer, prostate cancer or all other causes combined. I have underlined and bolded the last words of this sentence to emphasize the fact that vegetarians do not fair any better than their hamburger eating counterparts when death rates for all causes are considered. A more recent 2009 analysis (The EPIC-Oxford Study), employing the largest sample of vegetarians (33,883) ever examined came up with identical conclusions.71 I quote the authors, “Within the study mortality from circulatory diseases and all causes is not significantly different between vegetarians and meat eaters.” The results of this study71 and the earlier meta analysis,69 fly directly in the face of the American Dietetic Association’s suggestion that “vegetarian and vegan diets may provide health benefits in the prevention and treatment of certain disease.”28

Vegetarian Diets and Nutritional Deficiencies

The American Dietetic Association (ADA) advises us that, “…appropriately planned vegetarian diets, including total vegetarian or vegan diets are healthful and nutritionally adequate…28 This view is also shared by the USDA Choose My Plate guidelines which counsel us that, “Vegetarian diets can meet all the recommendations for nutrients.”142 The American Dietetic Association’s quote28 is a craftily written statement that is deliberately misleading and one sided. Taken at face value, it would appear that all vegetarian diets including vegan diets are nutritionally sound all by themselves and don’t require any additional nutritional supplements.

In order to get to the true meaning out of the ADA’s position statement, we need to dig deeper and determine what they mean by an “appropriately planned vegetarian diet.”  The ADA further hedges this statement by telling us that “…key nutrients for vegetarians include protein, n-3 fatty acids, iron, zinc, iodine, calcium, and vitamins D and B12.  A vegetarian diet can meet current recommendations for all of these nutrients.  In some cases, supplements or fortified foods can provide useful amounts of important nutrients.”28 Let’s dissect this masterly deceptive statement even further. The last line informing us that supplements and fortified foods “sometimes” are useful, is an outlandish understatement. In reality, it is not just in some cases that supplements and vitamin fortified foods are required, but rather in all cases for vegan diets and in most cases for lacto/ovo diets. Without supplementation vegetarian diets simply don’t work and invariably cause multiple nutrient deficiencies that not only adversely affect our health and wellbeing, but also that of our children.

Vegetarian Diets and Vitamin B12

Even informed vegetarians won’t argue that virtually all plant foods contain no vitamin B12 and that meat and animal foods are the only significant dietary source of this crucial nutrient. Additionally, we can’t synthesize B12 in our bodies. Consequently, if you decide to become a vegan, by default you will become vitamin B12 deficient unless you supplement your diet with this essential vitamin or eat B12 fortified foods.

Any lifelong dietary plan that requires nutrient supplementation on a regular basis makes no sense from an evolutionary perspective. You don’t have to be an evolutionary biologist to realize that wild animals don’t take nutritional supplements, nor do they normally develop vitamin deficiencies when living in their native environments. You will recall that not a single hunter-gatherer society consumed a vegetarian diet.26 This choice was not just a haphazard decision on their part, but rather was dictated by evolution through natural selection. If our ancestral foragers didn’t eat B12 containing animal foods, they developed vitamin B12 deficiencies which in turn impaired health and survival thereby worsening their chances of reproducing. Accordingly, any behavior that favored all plant diets would have been quickly weeded out by natural selection because of our genetic requirement for vitamin B12. Unlike modern day vegetarians, hunter-gatherers couldn’t simply pop a vitamin pill to make up for nutritional shortcomings in their diets. Without B12 supplementation, every hunter-gatherer who ever lived would have become vitamin B12 deficient if they didn’t eat animal food.

I want to emphasize that this flaw in nutritional logic is not just a minor point to be shuffled under the rug as the ADA28 and the USDA142 have done, but rather represents a colossal error in judgment for recommending vegan diets. To fully appreciate this massive breakdown in reasoning let’s examine the history of vitamin B12. Because it was the last vitamin to be discovered (1948), vitamin B12 only became available as a commercial supplement in the 1950s. Consequently, every person on the planet who consumed a strict lifelong vegan diet before B12’s discovery in 1948 would have been deficient in this critical nutrient. I wonder if the ADA28 and USDA142 would recommend vegan diets to U.S. citizens living prior to 1948 or only after 1948? This case in point shows how absurd their rationale for vegan diets appears – vegan diets are deadly before 1948 because they have no vitamin B12 but are “…healthful and nutritionally adequate…28 after 1948 because we can supplement this vitamin. OK – no big deal – nothing to get too excited about – just follow the ADA recommendations and make sure your vegetarian diet is “appropriately planned.”28 Right?

Unfortunately, most of the world’s vegetarians and vegans have not been able to figure out just exactly what an “appropriately planned28 vegetarian diet consists of, as almost all of them maintain deficient or marginal vitamin B12 concentrations in their bloodstreams. A 2003 study by Dr. Hermann and colleagues of 95 vegetarians revealed that 77% of lacto/ovo vegetarians were deficient in vitamin B12 whereas a staggering 92% of the vegans maintained deficiencies in this essential vitamin.52 The elegance of this study was that the researchers employed a powerful new procedure to precisely monitor vitamin B12 status in their subjects.50, 52 The simple measurement of vitamin B12 in the bloodstream often is misleading and doesn’t reflect true levels of B12 in our bodies.22, 64, 113 Nevertheless, a study (The EPIC-Oxford Study) which examined simple B12 concentrations in the blood of 231 ovo/lacto vegetarians and 232 vegans verified that B12 deficiencies were widespread within these groups.46 If we use the normal cutoff point (150 pmol/liter) as the measure for vitamin B12 deficiency in the blood, then the data from the EPIC-Oxford study shows that 73% of the vegans and 24% of the lacto/ovo vegetarians had vitamin B12 deficiencies.46 These two scientific papers are representative of nearly all other studies reporting vitamin B12 in vegetarians.1, 109, 118, 121 When this many people who follow vegetarian or vegan diets become vitamin B12 deficient, it is beyond comprehension to me why governmental agencies and national dietary organizations still stubbornly cling to the belief that plant based diets are healthful.

Even more disturbing is a report by Dr. Corinna Koebnick and co-workers in Germany showing that long term ovo/lacto vegetarian diets impair vitamin B12 status in pregnant women.74 The problem here is that maternal B12 deficiencies can then be handed down to the unborn fetus and to nursing infants who frequently have no other source of nutrition except for their mother’s vitamin B12 depleted milk.89, 107 B12 deficiency in pregnant women is not just a simple benign nutritional problem, but rather has potentially disastrous health outcomes for both mother and child. B12 deficiency in pregnant women is known to cause spontaneous abortions, weak labor, premature and low birth weight deliveries, birth defects, and the condition preeclampsia where mothers experience high blood pressure and damage to the liver, kidneys and blood vessels.7, 86, 87 Infants born from mothers with vitamin B12 deficiency frequently suffer from congenital malformations, irritability, failure to thrive, apathy, mental retardation and developmental problems.35 These data hardly support the ADA’s position that “Well-planned vegetarian diets are appropriate for individuals during all stages of the life cycle, including pregnancy, lactation, infancy, childhood….”28 In reality, the ADA’s recommendation of vegan and vegetarian diets “during all states of the life cycle28 is not only irresponsible, but in many cases is life threatening for mother, fetus and infant.

In Vegetarian and Vegan Diets: Nutritional Disasters Part 2, we’ll discuss why Vitamin B12 deficiencies are just as devastating to adults as they are to infants and expectant mothers.

Cordially,

Loren Cordain, Ph.D., Professor Emeritus

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Dill Curry Roasted Cauliflower

Roasting is an easy, quick, delicious approach to preparing vegetables. You might think cauliflower roasted in the oven becomes dry, but dry heat from the oven removes moisture from the vegetables, thereby concentrating their flavors. In fact, cauliflower is about 92% water, so after roasting it’s moist and tender.1 Like broccoli, cabbage, kale, and radishes, cauliflower belongs to the brassica family of vegetables. Brassica vegetables, also known as cruciferous vegetables, are exceptionally nutritious and should be featured prominently in our diets.

Brassica vegetables are rich in vitamin A, vitamin C, folate, and fiber. They are also high in glucosinolates, unique sulfur-containing compounds, which give them their distinctive bitter tastes and pungent aromas.2 Moreover, glucosinolates exhibit powerful healing properties, breaking down into indoles and isothiocyanates, which have been shown to inhibit the growth of cancer cells.3 Isothiocyanates also protect against pre-cancerous cells, helping the body eliminate them before they can damage DNA.4

Unfortunately, one of the most common ways of cooking cauliflower is boiling. Glucosinolates are water soluble, meaning they can leach into the cooking water. A 2007 study confirmed that boiling brassica vegetables results in significant glucosinolate losses, whereas steaming or stir-frying results only in minor losses.5 For the boiled vegetables, 90% of the lost glucosinolates were detected in the cooking water.

With brassica vegetables, you should also avoid cutting them long before consuming them. In the same study, glucosinolate losses of 75% were observed just six hours after shredding them.

In our recipe, cauliflower combines beautifully with fresh dill and Indian curry spices. Curry powders vary widely in terms of quality and composition, so be sure to read the product labels avoiding those with added salt. Enjoy!

INGREDIENTS

Serves 3-4

  • ½ – ¾ head of cauliflower
  • 1 red bell pepper, chopped
  • 2 medium tomatoes, chopped
  • 1 onion, finely chopped
  • 2 cloves garlic, pressed
  • 1 tbsp curry powder
  • Freshly ground black pepper
  • 1 tbsp coconut oil
  • 1-2 tbsp fresh dill, chopped
  • Olive oil for drizzling

DIRECTIONS

clark-cauliflower-6-wm
Ingredients
6 item(s) « 1 of 6 »

Christopher James Clark, B.B.A.
@nutrigrail
Nutritional Grail
www.ChristopherJamesClark.com

Christopher James Clark | The Paleo Diet TeamChristopher James Clark, B.B.A. is an award-winning author, writer, consultant, and chef with specialized knowledge in nutritional science and healing cuisine. He has a Business Administration degree from the University of Michigan and formerly worked as a revenue management analyst for a Fortune 100 company. For the past decade-plus, he has been designing menus, recipes, and food concepts for restaurants and spas, coaching private clients, teaching cooking workshops worldwide, and managing the kitchen for a renowned Greek yoga resort. Clark is the author of the critically acclaimed, award-winning book, Nutritional Grail.

See more recipes!

References

1. Nutrition Data. Retrieved July 8, 2014 from http://nutritiondata.self.com

2. Johnson, I.T. (January 2002). Glucosinolates: bioavailability and importance to health. International Journal for Vitamin and Nutrition Research, 72(1). Retrieved from http://www.ncbi.nlm.nih.gov/pubmed/11887749

3. Hayes, J.D., Kelleher, M.O. & Eggleston, I.M. (May 2008). The cancer chemopreventive actions of phytochemicals derived from glucosinolates. European Journal of Nutrition, 47(Supplement 2). Retrieved from http://www.ncbi.nlm.nih.gov/pubmed/18458837

4. Zhang, Y. (November 2004). Cancer-preventive isothiocyanates: measurement of human exposure and mechanism of action. Mutation Research, 555(1-2). Retrieved from http://www.ncbi.nlm.nih.gov/pubmed/15476859

5. Song, L. and Thornalley, P.J. (February 2007). Effect of storage, processing and cooking on glucosinolate content of Brassica vegetables. Food and Chemical Toxicology, 45(2). Retrieved from http://www.ncbi.nlm.nih.gov/pubmed/17011103

Vegetarian to Paleo | The Paleo Diet

Dr. Cordain,

After 30-40 years as a vegetarian/Natural Hygiene sympathizer, I have adopted the Paleo Diet. The diet is simple, sensible, and scientifically based – and I do well on it. Actually it was easy for me to adopt as, I had already deviated from Natural Hygiene by adding fish, dairy, whole grains, etc. to my diet. I now simply eat more fish, fruits, and veggies and have pretty much abandoned the dairy and whole grain. It’s an easy diet to follow – especially on an island where fresh fish are readily available for a buck a pound! One pleasant observation I have made while on the diet is that I have NOT lost weight. When I first became involved with vegetarianism I recall that my weight plummeted from a muscular 190+ to an unbelievably ripped 160. This weight loss was one factor that (fortunately) discouraged me from pursuing a strict vegetarian diet.

Stephen

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