The Paleo Diet - Loren Cordain [50]
My research group and I have published a paper in the British Journal of Nutrition describing our theory that dairy foods, grains, legumes, and yeast may be partly to blame for rheumatoid arthritis and other autoimmune diseases in genetically susceptible people. Legumes and grains contain substances called lectins. These substances are proteins that plants have evolved to ward off insect predators. Lectins can bind with almost any tissue in our bodies and wreak havoc—if they can enter the body, that is.
Normally, when we eat food, all proteins are broken down into basic amino acid building blocks and then absorbed in the small intestine. Lectins are different. They are not digested and broken down; instead, they attach themselves to cells in our intestines, where nutrient absorption takes place. The lectins in wheat (WGA), kidney beans (PHA), soybeans (SBA), and peanuts (PNA) are known to increase intestinal permeability and allow partially digested food proteins and remnants of resident gut bacteria to spill into the bloodstream. (Alcohol and hot chili peppers also increase intestinal permeability.) Usually, special immune cells immediately gobble up these wayward bacteria and food proteins. But lectins are cellular Trojan horses. They make the intestines easier to penetrate, and they impair the immune system’s ability to fight off food and bacterial fragments that leak into the bloodstream.
Surprisingly, we have found that many common gut bacteria fragments are made up of the same molecular building blocks as those found in certain immune system proteins and in the tissues under attack by the immune system. This matchup—of gut bacteria or food protein, immune system protein, and body tissue protein—may confuse the immune system, causing it to attack the body’s own tissues. A number of research groups worldwide have found that milk, grain, legume, and nightshade proteins can also trick the immune system into attacking the body’s own tissues by this process of molecular mimicry.
If you have an autoimmune disease, there is no guarantee that diet will cure it or even reduce your symptoms, but there is virtually no risk, and there are many other great benefits from the Paleo Diet that will improve your health.
Psychological Disorders
One of the least known benefits of grain-free diets is their ability to improve mental well-being. My colleague Dr. Klaus Lorenz of Colorado State University has extensively studied how cereals may influence the development and progression of schizophrenia. In a wide-ranging review study, Dr. Lorenz concluded that in “populations eating little or no wheat, rye and barley, the prevalence of schizophrenia is quite low.” Dr. Lorenz’s analysis included the clinical studies by Dr. F. Curtis Dohan of the Eastern Pennsylvania Psychiatric Institute. In studies spanning almost twenty-five years, Dr. Dohan reported time and again that the symptoms of schizophrenia were reduced in patients on grain-and dairy-free diets but worsened when these foods were returned to the diet. Exactly why cereals may alter mood and mental well-being is not entirely clear. But several studies have shown that when wheat is digested, it contains a narcoticlike substance that may affect certain areas in the brain that influence behavior. Similar substances called “casomorphins” have been isolated from cow’s milk; however, no one knows whether they can alter mood or behavior.
My colleague Joe Hibbeln at the National Institutes of Health has demonstrated that omega 3 fats may be effective in reducing depression, hostility, schizophrenia, and other mental disorders. His finding was confirmed in a four-month study of thirty manic-depressive patients by Dr. Andrew Stoll of the Brigham and Women’s Hospital in Boston. Dr. Stoll used medicine’s most powerful study tool, a double-blind, placebo-controlled trial, to compare the efficacy of omega 3 fats versus olive oil for treatment of manic-depressive illness. According to Dr. Stoll and his colleagues, “for nearly every outcome measure, the omega 3 fatty acid group performed