What do you have that chimps don’t have?

Besides your nice new iPhone and a receding hairline, what do modern Homo sapiens have that chimpanzees do not?

Image courtesy Wikipedia

I recently attended a conference in which Dr. Alessio Fasano spoke. Dr. Fasano is a noted celiac disease investigator who has dissected out the details of bowel “leakiness” characteristic of the disease. We also had an opportunity to speak: He is a brilliant and engaging scientist with a great sense of humor who laid out revelation after revelation.

Among the issues he highlighted was the fact that Homo sapiens have a gene that no other species possesses, a gene for a modified form of the protein haptoglobin. Ordinarily, haptoglobin is responsible for “cleaning up” free hemoglobin in the bloodstream. Hemoglobin is contained within red blood cells but, when damaged, free hemoglobin is released which is toxic; haptoglobin then “cleans” up the hemoglobin for disposal.

Humans are the only species with a modified form of haptoglobin, programmed by a gene acquired after human predecessors, Australopithecus, diverged from “Pan” apes, chimpanzees and bonobos, and transitioned towards ancestral Homo species. This protein is haptoglobin 2. The functions of this protein are distinct from haptoglobin’s role of hemoglobin scavenging.

Haptoglobin-2 has another name: zonulin. Zonulin proteins are found within intestinal cells, or enterocytes, with production/release triggered by various foreign bacteria, such as strains of E. coli and Salmonella Once triggered by bacteria, zonulin is responsible for creating bowel “leakiness,” allowing water to leak into the bowel: diarrhea, an adaptive response that develops in response to foreign invaders to flush them out. (Cholera toxin is the penultimate example of this effect, resulting in gallons of watery diarrhea.)

By a quirk of nature, the wheat protein, gliadin, mimics the effects of foreign bacteria and it, too, triggers zonulin. But this function is flawed in that it generates a two-way response: Not only can water exit, but intestinal contents are able to gain entry in the opposite direction: into the bloodstream.

Among the most fascinating findings of Dr. Fasano’s work: The gliadin-zonulin leak effect occurs not just in people with celiac disease or gluten-sensitivity; it occurs in everybody. The effect is longer and more pronounced (5-fold greater) in the enterocytes of people with celiac disease, but the effect of increased two-way leakiness spares nobody.

Only humans have the gene for haptoglobin-2 or zonulin. Chimpanzees and other primates do not have this gene. Interestingly, humans experience 75 different forms of autoimmune disease, while chimps experience none. Dr. Fasano presented compelling evidence, including increased zonulin blood levels, that this mechanism of intestinal leakiness underlies multiple inflammatory and autoimmune conditions, such as rheumatoid arthritis, autoimmune hemolytic anemia, Crohn’s disease, celiac disease, and type 1 diabetes.

Dr. Fasano was reluctant to declare that, based on his findings, bowel leakiness induced by wheat gliadin was sufficient reason to banish all wheat from the human diet, as he is a very careful scientist who feels he has to further explore this avenue and chart out all the details before making such a bold pronouncement. But I have no such qualms. And, besides, the potential for bowel leakiness is only one among many reasons to lose the wheat.

Lose the wheat, lose the zonulin-triggered bowel leakiness that can lead to the myriad forms of autoimmune and inflammatory diseases.

This entry was posted in Bowel permeability, Gliadin, Zonulins. Bookmark the permalink.

57 Responses to What do you have that chimps don’t have?

  1. DePaw says:

    Leaky gut doesn’t just cause auto-immune and allergies, but also is responsible for most mental disorders such as autism, schizophrenia, depression, bipolar, etc. The leaky gut can be healed though, look for Gut And Psychology Syndrome by Natasha Campbell-McBride, more info: http://www.gaps.me

  2. A Elizabeth says:

    Couldn’t there be other things in other foods that triggers the “zonulin leakiness,” or other toxic reactions? For example, nuts, seeds, and potatoes (in addition to grains and legumes) are high in lectins, which could trigger an immune response and bowel inflammation. Leafy greens contain phytotoxins that are meant to defend against consumption by bacteria and animals (including humans). Some people are histamine intolerant, which means that when they eat foods that are high in histamine (fish, yogurt, pumpkin, tomatoes, cheese, day-old poultry, cured meats) their blood vessels becoming dilated, and they get migraines, rosacea, urticaria, and pseudo-allergic reactions. It wouldn’t surprise me if every single food had some sort of poisonous effect. So what evidence do we have that wheat is especially poisonous?

    I must add that I am not pro-wheat. Eating a paleo-type diet makes complete sense to me. I’m just interested in seeing if the toxicity of wheat has been compared to the toxic effects of various other foods.

    • Dr. Davis says:

      On the issue of zonulin alone, I do not believe that other foods have been tested, nor components of other foods.

  3. Colleen says:

    You speak of autoimmune disease and wheat, can this also affect persons with multiple sclerosis?

    • Boundless says:

      If you google:
      “multiple sclerosis ketosis OR ketogenic”,
      you’ll get an eyeful, particularly regarding Dr. Terry Wahls. The WB recommendations are consistent with a keto diet. I haven’t researched any of it enough to have an opinion.

      I know even less about the methanol-MS connection.

  4. Martin says:

    Could development of zonulin be an evolutionary response to meat based diet?

  5. JD says:

    Hi Dr. Davis
    What is your opinion on ketosis? I am following Wheat Belly and am trying to lose weight. I have been reading about programs that promote a state of ketosis for weight loss and finding there are many different opinions on it. I’ve been following the program for 2 weeks now. Feeling great and full of energy. My cravings are under control! My abdominal issues are gone!

    • Boundless says:

      Dr. Davis oft-repeated net carb recommendation is 15 grams per meal, or per 6 hour period. That would be 45 to 60 grams per day, which is consistent with a ketogenic diet (and that’s something Dr. D. has also confirmed about the WB way).

    • Dr. Davis says:

      If you are achieving the goals you desire, JD, I do not believe that ketosis is obligatory.

      Ketosis is wonderful and not harmful, but it is also not an absolute requirement to succeed.

      • Boundless says:

        > Ketosis is wonderful and not harmful, but
        > it is also not an absolute requirement to succeed.

        This raises a question I can’t seem to find an answer for, and does not seem to be addressed in either WB book, and the internet in general is a cornucopia of conflicting data …

        What causes the accumulated fat to vanish if you aren’t in ketosis?

        Clearly, going low carb causes fat accumulation to cease.

        Clearly, being in ketosis burns accumulated fat, and on a low carb diet, we are probably in ketosis at least some of the time (say, while sleeping).

        How is fat metabolized other than by ketosis?

  6. Crayon says:

    Correlation does not equal causation. Just because they don’t necessarily eat meat doesn’t mean that is why they are so lean. There are plenty of other variables that you are leaving out with this.