Doctor's Note

See The Inflammatory Meat Molecule Neu5Gc for background, and How Tumors Use Meat to Grow: Xeno-Autoantibodies for the role it might play in cancer growth. Inflammation is also caused by exogenous endotoxins (see The Exogenous Endotoxin Theory), and is one of the three steps en route to fatal heart disease; see Arterial AcneBlocking the First Step of Heart Disease; and Making Our Arteries Less Sticky. Antioxidants found predominantly in plants (see Antioxidant Power of Plant Foods Versus Animal Foods) may also decrease inflammation within the body (see Anti-Inflammatory Antioxidants). Nuts may be particularly useful in this regard; see Fighting Inflammation in a Nut Shell. Tomorrow, we’ll close out the Neu5Gc story with Meat May Exceed Daily Allowance of Irony.

For further context, check out my associated blog post: Plant-Based Diets for Rheumatoid Arthritis.

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  • Chuck V

    Maybe you’ve covered in another video, but what is the biologic usage of Neu5Gc in the species that still synthesize it? Are there any primates that still synthesize Neu5Gc? Guesses as to why humans no longer make this

    • gb

      I’m interested in this question too. I will research and post anything good that i can find on this molecule’s evolution or possible purpose in other species, and why we lost it.

    • gb

      I did a little “non-scholarly” reading– general Wikipedia and Google searches, but not Google scholar– on this Neu5Gc molecule; here’s a very brief summary of what i found: We very likely had this molecule long ago, as other primates still make it. Neu5Gc is an integral part of the outer cell membrane (lipid layer) of red cells, and is a member of a broad class of similar-functioning molecules called “sialic acids” or “sialoglycoproteins.” (We still produce Neu5Ac, which is very similar to Neu5Gc, differing by an oxygen atom). We probably lost the ability to produce Neu5Gc because of some kind of parasitic epidemic– probably some kind of malaria variant, which was using the Neu5Ac molecule to recognize & enter human red cells. Some scientists believe this to be the case, because the modern malarial variant, Plasmodium falciprum, uses Neu5Ac to bind with red blood cells. Although malaria infection is still an epidemic today, the loss of Neu5Ac probably helped us evade a parasite that was decimating our (at that time) small populations of humans and putting selective pressure on humans to remove Neu5Gc from our red cells. It didn’t stop parasitic/malarial infection of our red cells, as we still get malaria infection– the malaria parasite has evolved with us, however it may have helped us evade a major parasite way back in the early mists of time.

      • Thea

        cool. Thanks for sharing this info. Much appreciated.

    • gb

      Seems that our cells don’t recognize Neu5Gc as being foreign, and happily use and incorporate it into our different tissues. The problem is that our immune systems still view it as being foreign and that’s where inflammation enters the story.

  • Last word should be ‘iron’, not ‘irony’?

    • carfree since ’93

      In Dr. Greger’s case, “irony” may be the correct term.

  • Does this mean that humans are not omnivores at all but herbivores? I’ve been vegan 5 years and have experienced only health benefits, but peole are constantly telling me that it is not our natural diet and that humans are omnivores.

    • Thea

      Heidi: I think of the terms: herbivore – omnivore – carnivore as a points on a continuum rather than discrete categories that species fall into. (Nature is rarely so accommodating as to provide clear-cut categories for anything.) So, where do humans fit on the continuum?

      My non-scholarly understanding is that while there is some evidence that puts humans partially toward the middle omnivore point on the continuum, human biology indicates that we are much closer to the herbivore end of things than omnivore.

      One of the Dr.s posting on this site listed some great info about the human gut supporting the assertion that humans are primarily (99.9%?) herbivore. (I don’t have a link at hand to that posting.) Here is a link to a site that I think does a great job of listing the case for humans being primarily herbivore. I found this information to be compelling. He has some other great pages too that you might want to check out.

      Hope you found this helpful.

    • Toxins

      We are indeed omnivores based on our ability to digest and use meat but this doesn’t necessarily make meat healthy for us. Here is the Okinawan diet, the population with the most centenarians per capita.

      Caloric Restriction, the Traditional
      Okinawan Diet, and Healthy Aging

      The Diet of the World’s Longest-Lived People and Its Potential Impact on Morbidity and Life Span
      Ann. N.Y. Acad. Sci. 1114: 434–455 (2007).

      TABLE 1. Traditional dietary intake of Okinawans and other Japanese circa 1950

      Total calories 1785
      Total weight (grams) 1262
      Caloric density (calories/gram) 1.4
      Total protein in grams (% total calories) 39 (9)
      Total carbohydrate in grams (% total calories) 382 (85)
      Total fat in grams (% total calories) 12 (6)
      Saturated fatty acid 3.7
      Monounsaturated fatty acid 3.6
      Polyunsaturated fatty acid 4.8
      Total fiber (grams) 23

      Food group Weight in grams (% total calories)


      Rice 154 (12)
      Wheat, barley, and other grains 38 (7)
      Nuts, seeds Less than 1 (less than 1)
      Sugars 3 (less than 11)
      Oils 3 (2)
      Legumes (e.g., soy and other beans) 71 (6)

      Fish 15 (1)
      Meat (including poultry) 3 (less than 1)
      Eggs 1 (less than 1)
      Dairy less than 1 (less than 1)


      Sweet potatoes 849 (69)
      Other potatoes 2 (less than1)
      Other vegetables 114 (3)
      Fruit less than 1 (less than 1)
      Seaweed 1 (less than 1)
      Pickled vegetables 0 (0)
      Foods: flavors & alcohol 7 (less than 1)

      Data derived from analysis of U.S. National Archives, archived food records, 1949 and based on survey of 2279 persons.

      Some points

      Their diet was 85% carb, and 6% fat. Sweet potatoes (a Japanese sweet potato) made up almost 70% of their calories. Nuts were less than 1% of calories (the equivalent of 1/10 of an ounce a day) Oil was less than 2% of calories (which is about 1 tsp a day) and sugars were less than 1% of calories (less than a tsp a day)

      The total animal products including fish was less than 4% of calories which is less then 70 calories a day. That is the equivalent of around 2 oz of animal products or less a day

      • WG Fargo

        Two points: 1. Sadly the present day Okinawans diet has moved to the West thanks to the influence of the American military and many Okinawans are now very sick people. They were not protected by their genes. 2. The post WW II diet, as recorded in this one survey, may not have been typical but it is probably a good indicator. They ate much less than 2 oz. of animal products, and most of what they did eat was fish. The survey shows they ate less than 5 grams of meat (including poultry), eggs and milk ( 1/5 of an oz.).

        • Toxins

          To point 1, that is acknowledged, as this is from the 1950’s. As to point 2, where is your evidence?

          • Herbivore

            We’re herbivores.

          • Toxins

            Although this would be a nice thought, this is false, as we can utilize nutrients from meat, and the Inuits can survive completely off of it, so we are indeed clearly omnivores. The issue is more how much meat we eat, and that should be minimal. I personally eat none because of health detriments seen with its consumption but even the healthiest native populations still include some animal products in their diet.

    • Wade Patton

      I think we’re herbivores optimally, but can survive as omnivores if/when necessary as a survival tool (sub-optimally). We’re just about to eliminate our species of the Westernized type. Then the herbivores can take over again, cycle repeats if we (as a species) don’t learn from it.

  • chris m

    Has the Neu5Gc been found in cheese or milk? I’m slowly transitioning to vegetarianism but do occasionally make a veggie pizza with cheese.