Tag Archives: offal

Is Paleo Sustainable for 7 Billion People? | The Paleo Diet

Can our planet support 7 billion people following the Paleo Diet? We cannot dispute that there are negative environmental factors, such as excessive water and fossil energy use and large emissions of greenhouse gases, resulting from the standard process of agriculture and livestock farming. These methodologies make it seem unrealistic that even our current food production system can sustain our planet, let alone support the Paleo diet alone.

Obviously, no one wants to contribute to an ecological collapse. If 7 billion people adopted a diet higher in animal meat under the existing methods of production, it would continue to tax our planet. However, the rising numbers of diet related illnesses1 indicate that something has to change when it comes to how we produce food and how we choose to eat. Let’s take a closer look at how we can all participate in following a sustainable, environmentally friendly approach to the Paleo diet.


We are truly what we eat. Although pastured meats cost more, this money is an investment in both the environment and your future physical wellbeing. If we suppose there is a greater demand for sustainable animal protein, then agricultural boards and organizations can provide more research and education to ranchers to reduce their use of water, pesticides, and feed grain. In turn, this may bring the price per pound down as it becomes more desired on grocery shelves.

Commercial livestock production stresses the land. However, with proper methodologies, ruminants can actually be benefactors to preserve ecosystems, produce food from inedible sources, restore soil fertility, and recycle plant nutrients. 2EAT THE WHOLE ANIMAL

Boneless, skinless chicken and tenderloins of beef taste good, but there is more to the animal than muscle to embrace on a regular basis. As previously covered in Offal, Not So Awful: Organ Meats and the Paleo Diet, our hunter-gatherers ancestors consumed the entire animal from nose-to-tail and recognized the wealth of nutrients obtained from the brains, liver, kidney, heart, blood, lungs, and all other visceral organs.4 The carcasses and bones can also be used to make rich, nourishing bone broths, and the fat can be used to make high-quality cooking oil.5 The whole animal offers minerals, nutrients, and calories to properly fuel our bodies, while also respects the food source where it came from.


Ingesting insects, or entomophagy, is probably completely off your radar and most likely more repulsive than eating organs. However, insects form part of the traditional diets of at least 2 billion people in the world, including individuals in Mali who hunt and eat grasshoppers. There also existed a long history of insect eating 25-50% of North American tribes.6

Significant environmental benefits exist to support cultivating insects for food. They are highly efficient to produce. For example, crickets require only 2 kg of feed for every 1 kg of bodyweight gain, compared to the 8 kg a cow needs.7 Insects produce very little greenhouse gas, and can be cultivated on using very little water or land, such as an organic side-stream, which reduces environmental contamination.8 Insects are also a great source of fat, protein, vitamin, and minerals.9 Ease into the idea of eating insects by using cricket flour or cacao covered ants, which can be incorporated into your Paleo cooking.

If we evaluate the current food production system and dietary norms based on the rising levels of lifestyle related illnesses, the obesity epidemic, and the negative environmental impacts of farming, we can conclude that the entire system needs to change. The Paleo diet has been shown to reduce inflammation,10 improve waistlines, and regulate blood sugar and insulin response.11 We cannot afford to not choose the foods that best serve our bodies genetically, while also protect our planet.



[1] WHO, Joint, and FAO Expert Consultation. Diet, nutrition and the prevention of chronic diseases. Geneva: World Health Organization, 1990.

[2] Janzen, H. H. “What place for livestock on a re-greening earth?.” Animal Feed Science and Technology 166 (2011): 783-796.

[3] Cingolani, Ana M., et al. “Can livestock grazing maintain landscape diversity and stability in an ecosystem that evolved with wild herbivores?.” Perspectives in Plant Ecology, Evolution and Systematics 16.4 (2014): 143-153.

[4]  Cordain L, Eaton SB, Brand Miller J, Mann N, Hill K. The paradoxical nature of hunter-gatherer diets: Meat based, yet non-atherogenic. Eur J Clin Nutr 2002;56 (suppl 1):S42-S52.

[5] Webb, E. C., and H. A. O’neill. “The animal fat paradox and meat quality.” Meat Science 80.1 (2008): 28-36.

[6] Available at: //www.fao.org/docrep/018/i3253e/i3253e.pdf. Accessed on February 4, 2015.

[7] ATES, S., et al. “Performance of indigenous and exotic× indigenous sheep breeds fed different diets in spring and the efficiency of feeding system in crop–livestock farming.” The Journal of Agricultural Science: 1-16.

[8] Paoletti, Maurizio G. Ecological implications of minilivestock: potential of insects, rodents, frogs and snails. Science Publishers, Inc., 2005.

[9] Available at: //www.fao.org/docrep/018/i3253e/i3253e.pdf. Accessed on February 4, 2015.

[10] O’Keefe, James H., Cordain, L. “Cardiovascular disease resulting from a diet and lifestyle at odds with our Paleolithic genome: how to become a 21st-century hunter-gatherer.” Mayo Clinic Proceedings. Vol. 79. No. 1. Elsevier, 2004.

[11] Ballard, K et al.Dietary carbohydrate restriction improves insulin sensitiv­ity, blood pressure, microvascular function, and cellular adhesion markers in individuals taking statins.Nutr Res.2013 Nov;33(11):905-12.

Organ Meats, Bones, and the BDA's Curioius Food Group Eliminations

Last week the British Dietetics Association (BDA), the UK’s largest organization of nutrition professionals, launched an impetuous assault on the Paleo Diet, ranking it second among their “Top 5 Worst Celebrity Diets to Avoid in 2015.” Did you notice the double negative here? Did the BDA intend to call their ill-reasoned hit piece ‘top 5 worst diets to embrace?’ Or did they mean ‘top 5 best diets to avoid?’ The BDA’s hasty grammatical error epitomizes the carelessness of their anti-Paleo sentiments.

“There is absolutely no need to cut any food group out of your diet,” the BDA insists.1 They contend that eliminating entire food groups like dairy and cereals promotes nutrient deficiencies. There are many problems with this contention. In his rebuttal to the BDA, Dr. Mark J. Smith succinctly outlines how the Paleo Diet, far from being deficient, actually improves nutrient uptake compared to the USDA’s MyPlate.

Another embarrassing problem is that MyPlate, as well as the UK government’s Eatwell Plate, which the BDA endorses, also eliminates entire food groups—organ meats and bones. Dairy and cereals make up nearly one-half the Eatwell Plate and about one-tenth of Eatwell goes toward “Food and drinks high in fat/sugar,” but where are organ meats and bones? Are we to believe that high-sugar foods are more important?

Heart, liver, sweetbread, and other organs are extremely nutrient-dense. Besides providing high-quality fat and protein, they also contain very high levels of vitamins and minerals. Beef liver, for example, contains potent amounts of vitamin A (in its absorbable retinol form), vitamin B12, other B vitamins, iron, and selenium.

Organ meats, especially liver, are also rich in choline, an essential nutrient, which plays critical roles in brain development and homocysteine metabolism.2 Muscle meats are particularly rich in methionine, which in excess generates homocysteine.3 Elevated homocysteine is a well-established cardiovascular disease marker, thus eating choline-rich foods is particularly important to buffer and balance dietary methionine.

Glycine is an amino acid found in significant amounts in bones, skin, and connective tissue. Glycine also helps balance methionine, thereby preventing methionine toxicity.4 The BDA’s dietary recommendations, however, include neither organ meats nor bones. The organization has completely eliminated these important food groups while criticizing the Paleo Diet for eliminating dairy and cereals.

There are good reasons to eliminate dairy and cereals, which Dr. Cordain has comprehensively documented, but why would anyone want to eliminate organs and bones? The Paleo Diet, of course, strongly encourages “nose-to-tail” eating, consuming the entire animal, including the organs and bones, not just muscle meats as per the BDA’s recommendations.

Nose-to-tail eating is the most balanced way of consuming animal foods, yet the BDA curiously calls the Paleo Diet “unbalanced.”5 The BDA has recycled the same tired criticism of so many other Paleo detractors, claiming the Paleo Diet unnecessarily and even dangerously eliminates entire food groups. We invite the BDA to explain why they themselves have eliminated entire food groups, particularly the most nutrient-dense food group of them all—organ meats. We’re not, however, holding our breaths waiting for this explanation, so we suggest you continue with the Paleo template, not forgetting to regularly include both bone broth and organ meats.

Christopher James Clark, B.B.A.

Nutritional Grail

Christopher James Clark | The Paleo Diet TeamChristopher James Clark, B.B.A. is an award-winning 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.


[1] The Association of UK Dietitians. (Dec 8, 2014). Top 5 Worst Celebrity Diets to Avoid in 2015. Retrieved from https://www.bda.uk.com/news/view?id=39&x[0]=news/list

[2] Jensen, HH, et al. (Mar 2007). Choline in the diets of the US population: NHANES, 2003–2004. The FASEB Journal, 21 (Meeting Abstract Supplement) LB46. Retrieved from //www.fasebj.org/cgi/content/meeting_abstract/21/6/LB46-c

[3] Miller, AL. (Feb 2003). The methionine-homocysteine cycle and its effects on cognitive diseases. Alternative Medicine Review, 8(1). Retrieved from //www.ncbi.nlm.nih.gov/pubmed/12611557

[4] Sugiyama, K, et al. (Jun 1987). Effect of dietary glycine on methionine metabolism in rats fed a high-methionine diet. Journal of Nutritional Science and Vitaminology, 33(3). Retrieved from //www.ncbi.nlm.nih.gov/pubmed/3668700

[5] The Association of UK Dietitians. (Dec 8, 2014). Top 5 Worst Celebrity Diets to Avoid in 2015. Retrieved from https://www.bda.uk.com/news/view?id=39&x[0]=news/list

Tongue: A Hunter Gatherer Delicacy

Back in the summer of 1969 as a strapping, young Forest Service firefighter based out of Markleeville California, I had the pleasure to dine in the world famous Basque establishment, The Overland Hotel, Bar and Restaurant, located in Gardnerville, Nevada. Unfortunately I discovered the Overland has just recently closed its doors. Nevertheless, my memories of a singular summertime dinner with my firefighting buddies at the Overland linger to this day.

For those of you who have never visited a western Basque restaurant, you are in for a surprise. Meals are generally served family-style, where patrons sit at communal tables and are collectively provided unlimited amounts of food and drink – the only caveat being that your dining selection is limited just to the items the hosts have prepared for dinner. OK – way different from the normal U.S. restaurant, but as you may well surmise, this ambiance creates a festive dining experience promoting conversation and good times for all – particularly when the first carafe of excellent Spanish, red wine is served up in boundless quantities for everyone at your table.

From my memory of that long ago dinner, a simple salad of lettuce, cucumbers and tomatoes dressed with vinegar and olive oil came first, followed by an incredibly delicious dish which I had never experienced in my entire life – beef tongue. My Basque hosts enjoyed this delicacy throughout their lives as had their ancestors before them. However, as a naïve American teenager raised upon the typical junk food fare of the 1950’s and 1960’s, I had no idea of the delicacy I would soon be enjoying. Only decades later would I finally appreciate that tongue was a highly nutritious organ meat that had been savored by humans from our very origins.

Archaeological Evidence

The top photograph shown below is from the inside surface of a fossilized mandible (jawbone) of either a wildebeest or a hartebeest. This artifact was found in East Africa and has been dated to 2.5 million years ago1 – a time slightly before the human genus (Homo) first arose. In the photograph you can make out a slight scratch on the inside surface of the jawbone. This scratch has been magnified and then magnified again in great detail with a scanning electron microscope.1 The scratch is actually a cut mark made by one of our ancient hominid ancestors who used a sharp stone flake to remove the tongue.1 This remarkable archaeological discovery represents convincing evidence that tongue was a favored organ meat from the very beginnings of humankind.

The archaeological record for virtually all stone age hominids and historically studied hunter gatherers demonstrates that tongue removal and consumption in prey mammals was a nearly universal practice.2-4 Similarly, modern humans living in 19th century America seemed to also have a great fondness for tongue. In just four short decades, American buffalo hunters slaughtered bison almost to the point of extinction, reducing their numbers from an estimated 30 million to less than 1,000 animals.5 Drury and Clavin write, “When whites killed the buffalo, the animals were skinned where they fell, everything but their hides and tongues left to rot on the prairie The hunters considered the meat worthless . . .”5


Figure 1. Scanning electron microscopy of a stone cut mark on the medial surface of an Alcelaphine bovid (wildebeest/Hartebeest) mandible made during tongue removal (reference 1).

So, just what was it about the tongues of prey mammals that made this organ so desirable to our hunter gatherer ancestors, even 2.5 million years ago? Why was tongue consumed raw, first and foremost after a successful kill? And why too did 19th century American buffalo hunters abandon the entire edible bison carcass except to eat the tongue? These are good questions raised by archaeological and historical evidence. However, these questions could have only been answered in the past 50 years or so with the development of modern analytical instruments capable of measuring the nutrient composition of tongue. As you will soon learn, tongue nutrient content has been infrequently analyzed.

Nutritional Analysis of Tongue

In the United States tongue is rarely or never consumed except as in ethnic dishes, such as the Basque dinner I enjoyed at the Overland. It should be mentioned that most of us in the western world are simply missing out upon this delicious organ meat. My first taste of tongue came that summer evening at the Overland in a brilliant tomato and green pepper sauce recipe stewed slowly to perfection. The tough outer surface of the tongue had been sliced away, so there was no inkling that the soft, tasty tongue I was eating was anything other than a great cut of tender, flavorful meat.

OK. Back to the nutritional basics. Why is tongue so desired in non-westernized populations and why is it and so flavorful? First and foremost, it is a high fat cut of meat, but moreover, it contains the types of fatty acids which we deem to be flavorful and which have proven therapeutic health effects. In the table below, I have characterized the fat, protein and caloric content in a 100 gram portion (~1/4 pound) of beef, pork, lamb and caribou tongue.

Tongue Table 1

These numbers at first glance may not seem to be extraordinary or remarkable to anyone other than a nutritional scientist, knowledgeable in wild game nutrient composition. Let me explain. Tongue is an incredibly concentrated source of fat on a caloric basis. In wild mammals, muscle meat typically contains only 20-22% of its calories as fat with the balance as protein.7, 8 Contrast this percentage to the fat calories (65-80%) found in tongue, and you will “get why” our ancestors preferentially ate tongue at every available opportunity.

Protein is physiologically toxic at levels beyond about 35-40% of calories,7-9 whereas fat can be consumed in unlimited quantities. Hence, the foraging strategy of our hunter gatherer ancestors was always to maximize fat intake (ergo fatty organs and meat: tongue, marrow, brains, perinephral fat, mesenteric fat, retro-orbital fat, lips, liver, etc.) while restricting protein intake (lean muscle meat) to our physiological ceiling.7-9

To put it simply, tongue is one of the highest fat organs in mammals, and our hunter gatherer ancestors realized that tongue prevented symptoms of protein poisoning, was more satiating than muscle meat and simply made them feel good. If you can get over the western stigma of eating “tongue,” you will taste one of the ancient delicacies of humankind. Why does properly cooked tongue taste so delicious? Let me enlighten you with the very first study ever of tongue fatty acid composition.10

Until 2013, the fatty acid composition of tongue had never been reported in the available scientific literature. Thanks to Dr. Hoffman from the University of Stellenbosch in South Africa we now have preliminary data showing that tongue contains a healthy fatty acid profile, but also is known to be flavorful to human taste preferences. Below is a table depicting the fatty acid profile of tongue in two breeds (Dorper and Merino) of sheep.

Tongue Table 2

Notice that tongue contains very high concentrations of monounsaturated fatty acids, particularly oleic acid (18:1n9c). Oleic acid is the same health promoting fatty acid found in nuts and olive oil. Our research group has demonstrated that oleic acid is also found in high concentrations in bone marrow.11 Finally take a look at the relatively high concentrations of 18:0 present in tongue. This saturated fatty acid is called stearic acid and is one of the few saturated fatty acids which lowers blood cholesterol levels.

Besides its healthful fatty acid profile, tongue has a delicious flavor found in few other animal tissues. Animal foods containing high amounts of oleic acid are savory because these fats maintain a smooth, rich texture compared to shorter chain saturated fatty acids such as palmitic acid (16:0) which is a storage fat. Pemmican made with marrow (also high in oleic acid) was preferred by North American Indians compared to pemmican made with storage fat (palmitic acid). So, do yourself a favor give beef tongue a try. Here’s a recipe from our kitchen that you may enjoy.

Apricot Raisin Tongue

Serves 4

  • 1 beef tongue
  • 1 tbsp garlic powder
  • 3 bay leaves
  • 1 tablespoon marjoram
  • 1 lb dried apricots (nonsulfured; available at health food stores)
  • 1 lb tomatoes, peeled
  • 1/2 cup lime juice
  • 1/2 cup lemon juice
  • 1/4 tsp basil
  • 1/4 tsp ground red pepper
  • 1 tbsp mustard powder
  • 1/2 cup raisins


  1. Put the tongue in a large pot, cover completely with water, and bring to a rapid boil.
  2. Replace the water and bring to a second boil.
  3. Replace the water again and bring to a slow, easy boil.
  4. Add the garlic powder, bay leaves, and marjoram, and cook until done, about 2 hours.
  5. Discard the water and bay leaves. Skin the tongue and let it cool. Cut into thin slices.
  1. Preheat the oven to 350°F.
  2. Place the apricots in a saucepan.
  3. Puree the tomatoes in a blender and add the tomato sauce and the remaining ingredients to the apricots, and bring to a boil. Continue to simmer until the mixture thickens.
  4. Layer the sliced tongue in a flat casserole dish and pour the sauce over it.
  5. Bake for about 20 minutes.

Loren Cordain, Ph.D., Professor Emeritus


1. de Heinzelin J1, Clark JD, White T, Hart W, Renne P, WoldeGabriel G, Beyene Y, Vrba E. Environment and behavior of 2.5-million-year-old Bouri hominids. Science. 1999 Apr 23;284(5414):625-9.

2. Wheat JB. A Paleo Indian bison kill. Scientific American. 1967; 216:109-117.

3. Todd, LC., Rapson, DJ. “Formational analysis of bison bonebeds and interpretation of Paleoindian subsistence.” Le Bison: Gibier et Moyen de Subsistance des Hommes du Paléolithique aux Paléoindiens des Grandes Plaines. Éditions APDCA, Antibes (1999): 479-499.

4. White TE. Observations on the butchering techniques of some aboriginal peoples number 2. American Antiquity 1953;19:160-164.

5. Drury B, Clavin T. The Heart of Everything that Is. Simon and Schuster, New York, 2013, pp 183-184.

6. Nutritionist Pro. Version 4.7.0. Axxya Systems, //www.nutritionistpro.com/, 2014.

7. Cordain L, Brand Miller J, Eaton SB, Mann N, Holt SHA, Speth JD. Plant to animal subsistence ratios and macronutrient energy estimations in world wide hunter-gatherer diets. American Journal of Clinical Nutrition, 2000, 71:682-92.

8. Remko S. Kuipers1, Martine F. Luxwolda1, D.A. Janneke Dijck-Brouwer1, S. Boyd Eaton, Michael A. Crawford, Cordain L, and Frits A.J. Muskiet. Estimated macronutrient and fatty acid intakes from an East African Paleolithic diet. Brit J Nutr , 2010 Dec;104(11):1666-87.

9. Rudman D, DiFulco TJ, Galambos JT, Smith RB, Salam AA, Warren WD. Maximal rates of excretion and synthesis of urea in normal and cirrhotic subjects. J Clin Invest 1973;52:2241-49.

10. Hoffman LC, Laubscher LL, Leisegang K.Nutritional value of cooked offal derived from free-range rams reared in South Africa. Meat Sci. 2013 Mar;93(3):696-702

11. Cordain L, Watkins BA, Florant GL, Kehler M, Rogers L, Li Y. Fatty acid analysis of wild ruminant tissues: Evolutionary implications for reducing diet-related chronic disease. Eur J Clin Nutr, 2002;56:181-191.

Offal – Not So Awful: Organ Meats and The Paleo Diet

When we think of eating organs, the first thought that comes to mind is gray, stinky liver and onions served in a diner. The thought is far from the delicious aromas that get the salivary juices flowing.1 Whether it’s the unappetizing idea or sheer intimidation, organ meats, or offal, carry a unique flavor profile that might take some time to perfect and for your taste buds to appreciate.2

It isn’t surprising Western cultures prefer muscle meat (steaks, thighs, ribs, loins) of animals.3 Yet, our hunter-gatherers ancestors consumed the entire animal from nose to tail and recognized the wealth of nutrients obtained from the brains, liver, kidney, heart, blood, lungs, and all other visceral organs. From their fatty acid profiles, and high micronutrient (vitamins and mineral) contents, the inclusion of offal on your Paleo menu is a no brainer. 4 Organ meats are more nutrient dense than muscle meats, containing higher levels of vitamin B1, B2, B6, folate, B12 and A, D, E and K. They are also packed with minerals like phosphorus, iron, copper, magnesium, iodine, calcium, potassium, sodium, selenium, zinc and manganese. Organ meats also contain high amounts of essential fatty acids, including arachidonic acid and the omega-3 fats EPA and DHA.5, 6

But how to beat the struggle to incorporate organ meats into your Paleo Diet when that grilled steak is calling your name? Overcome the initial fear and apprehension and start experimenting. For the foods that have the initial “ick” factor, hide them in something else. As you become more adventurous and accustomed to the different texture and flavors of the organ meats, there is no limit to the number of delicious and nutrient dense recipes that you can attempt to make with them, as you diversify your diet from just eating common cuts of meat. The most widely available offal at your local grocery store, and perhaps the simplest to begin with, are liver, kidney, tongue and heart.

Liver is one of the most popular organ meats and it is also one of the most concentrated food sources of vitamin A.7 Raw liver can be frozen for 14 days to kill any parasites or pathogens and then grated into mashed vegetables, such as cauliflower, or into scrambled eggs, soups and stews.8 It can also be ground in a food processor, and cooked into meatloaf, burger patties, or into a dairy-free pate served on cucumber slices.

Kidney is particularly high in Vitamin B12, selenium, iron, copper, phosphorus and zinc.9 They are meaty in texture, have a tender flavor, and are best slow cooked at a low temperature. The easiest way to get started is to braise them with vegetables using a rich homemade bone and marrow broth.

Heart is a technically a muscle, so it can be an easier organ to palate as it resembles a steak or a roast. Many consider beef heart a superfood given its high CoQ10, B vitamins, folate, selenium, phosphorus, zinc, and amino acids. 10 Beef heart can be marinated in vinegar overnight, then sliced into 1” thick slabs, and seared on the outside before serving. Thinly sliced heart can also be dried into flavorful jerky using a dehydrator or placed in the oven on the lowest setting.

As you branch out into your offal exploration, visit an ethnic grocer or a butcher for more exotic organs (at least for a Western Diet), such as brain, tripe (the edible parts of the stomach), sweetbreads (the thymus gland or pancreas), and “oysters” (the testicles). You might be surprised to discover for yourself why our ancestors prized organs and preferred to eat them instead of skinless, boneless chicken breasts.

1. Pedersen A, Bardow A, Jensen, S.B, Nauntofte, B. Saliva and gastrointestinal functions of taste, mastication, swallowing and digestion. Oral Diseases, 2002, 8: 117–129.

2. Drewnowski A. Taste preferences and food intake. Annual Review of Nutrition, 1997 July, Vol. 17: 237-253.

3. Cordain L, Brand Miller J, Eaton SB, Mann N, Holt SHA, Speth JD. Plant to animal subsistence ratios and macronutrient energy estimations in world-wide hunter-gatherer diets. American Journal of Clinical Nutrition, 2000, 71:682-92.

4. Cordain L, Eaton SB, Brand Miller J, Mann N, Hill K. The paradoxical nature of hunter-gatherer diets: Meat based, yet non-atherogenic. Eur J Clin Nutr 2002;56 (suppl 1):S42-S52.

5. Park, Y. W. and Washington, A. C., Fatty Acid Composition of Goat Organ and Muscle Meat of Alpine and Nubian Breeds. Journal of Food Science, 1993, 58: 245–248.

6. Nicklas TA, Drewnowski A, O’Neil CE. The nutrient density approach to healthy eating: challenges and opportunities. Public Health Nutr. 2014 Aug 28:1-11.

7. Available at: The United States Department of Agriculture Agricultural Research Service. National Nutrient Database for Standard Reference Release 27. Accessed on September 29th, 2014.

8. Available at: //www.westonaprice.org/health-topics/the-liver-files/. Accessed on September 29th, 2014.

9. Available at: //www.eatthismuch.com/food/view/beef-kidneys,3447/. Accessed on September 29th. 2014.

10. Available at : The United States Department of Agriculture Agricultural Research Service. National Nutrient Database for Standard Reference Release 27. Accessed on September 29th, 2014.

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