A question I’m asked almost daily, is ‘why is there such a rise in food allergies and intolerances? I believe there are many answers to this question, but the one I will discuss today has to do with the gut – both the balance of organisms, called the ‘microbiome’, and intestinal permeability. Issues with the gut, in combination with the changes in our food supply over the past 100 years could account for the huge rise in allergies that we see today.
The Gut Microbiome:
- The microbial gut flora is an important part of your immune system, and this is easily disrupted by antibiotic use, high sugar diets, and also use of hormonal birth control.
- This theory is based on the hygiene hypothesis, where the use of antibiotics, antibacterial cleansers and even hand sanitizers have gotten rid of both the harmful and helpful bacteria.
- In one study documented in the Journal of Allergy and Clinical Immunology (http://www.motherjones.com/environment/2014/03/a1-milk-a2-milk-america), children with less diverse gut bacteria actually appear to have a higher sensitivity to allergies than children with more diverse gut bacteria.
- Having an optimal and diverse balance of healthy bacteria in the intestinal tract is essential for a healthy immune system.
Intestinal Permeability or “Leaky Gut Syndrome”:
- Intestinal permability is the second way that food allergies begin in the gut. The body’s first line of defense is the lining of the gastrointestinal tract, acting as a barrier to prevent microorganisms and toxins from entering the bloodstream. When this lining is broken down, toxins from bacteria and yeast, as well as larger food particles can pass through.
- Gut-associated lymphoid tissue, also called GALT, is the second line of defense which is a large amount of lymphatic tissue surrounding the gastrointestinal tract. Large particles passing through the gut lining cause an immune response, and antibody production, thus causing food allergies and intolerances.
- Leaky gut syndrome puts constant stress on the immune system, as it is always reacting to particles passing through, thus creating a chronic state of inflammation.
- It is essential to repair intestinal permeability, to reverse food allergies and intolerances.
How Foods Affect the Gut Microbiome and Intestinal Permeability:
- Dairy – Cow’s milk dairy products contains over 25 different molecules which have been identified by scientists as having the potential to cause an allergic food response.The protein that is focused on most in the development of allergies is called A1 beta-casein, which composes about 30% of the protein in milk, in North America and large parts of Europe. This protein is releases beta-casomorphin7 (BCM7), an opioid with a structure similar to that of morphine. BCM7, when passed through the gut lining (remember leaky gut), is associated with type I diabetes, other autoimmune disease, and also autism. Interestingly, cow’s milk from Asia and Africa, other cow breeds (Jersey and Guernsey), goat’s milk and even human breast milk contain a different form of the casein protein, called A2 beta casein which is much less allergenic. Here is an excellent article on this topic: http://www.motherjones.com/environment/2014/03/a1-milk-a2-milk-america
- Gluten – It is no surprise that gluten intolerance and celiac disease are both on the rise right now, and by the number of people who feel better without wheat in their diets, it is clearly more than a health trend. There are a few reasons for this rise. Number one, modern wheat has been altered in many ways. It has been hybridized (crossing different strains to generate new characteristics); backcrossed (repeated crossing to winnow out a specific trait, and hybridized with non-wheat plants (to introduce entirely unique genes), all resulting in a change in the protein structure of the wheat plant, that is less familiar to our immune systems. In sensitive people, gluten can also cause the cells in the gut lining to release zonulin, a protein that can break apart the tight junctions holding your intestinal lining together, hence creating a leaky gut. The final reason for the rise in gluten intolerance, is that we eat too much of it. As part of a healthy diet, you could very easily eat 3-4 servings of wheat per day in the form of cereals, whole grain breads, pastas and treats. Any food that we eat in such abundance poses this risk. (Read more about how gluten affects the immune system here: http://www.huffingtonpost.com/amy-myers-md-/effects-of-gluten-on-the-body_b_3672275.html)
- Eggs – Eggs are a particular problem for people with intestinal permeability, due to the proteins contained in the egg white. The protein that appears to cause the most problems from eggs is called lysozyme, which easily binds with other egg proteins, and also gut borne bacteria peptides. When these protein complexes pass through the intestinal lining, they can provoke an immune response with the capacity to promote allergy and autoimmune disease. From this theory, eggs may not be a problem for those without a leaky gut, and interestingly, babies under the age of 1 year naturally have a semi-permeable gut lining. Read more about the science off egg allergy here: http://thepaleodiet.com/lysozyme-clarification/)
- Corn and Soy – Corn and soy (as well as canola) are the most prevalent genetically modified (GMO) foods in our current food supply. Most GMO crops are engineered to tolerate high amounts of an herbicide called Roundup, whose active ingredient is glyphosate. Glyphasate, and an insecticide called Bt-toxin (found in all non-GMO corn products) end up in most of the soy corn products that we buy, and in almost all processed and packaged foods. Bt-toxin and glyphasate have been linked to: intestinal permeability, imbalanced gut flora, allergies and impaired digestion. Ingestion of GMO foods therefore affects the gut flora and lining, creating a risk for the development of food allergies. The key here is to choose organic or non-GMO versions of corn and soy, if you choose to include them in your diet, as it appears that GMO foods are part of the cause of intestinal permeability.
From the information above, it appears that the key to preventing and reducing food allergies and intolerances comes back to a healthy balance of flora in the intestinal tract (the microbiome), and an integral gut lining. If you are someone with multiple allergies or intolerances, it is likely that one or both of these are out of balance. The good news is that these are issues that can be corrected with diet, rebalancing the intestinal flora and repairing the gut lining.