GUT BACTERIA HELP PROTECT AGAINST FOOD ALLERGIES

A  new study performed in mice has found that the presence of Clostridium gut bacteria plays an important role in preventing the development of food allergies.  In recent years, food allergy rates among children in the US have risen sharply -- increasing approximately 50% between 1997 and 2011.  Studies have shown a correlation between antibiotic and antimicrobial use and risk of food allergens, suggesting that disruptions of the body's microbiota, the population of bacteria that naturally live in and on people, might play a role in the development food allergies.

To see how changes in the microbiota of the intestines might influence allergic responses to food, researchers compared the immune response to peanuts (one of the most allergenic foods) of germ-free mice (mice reared in sterile conditions so that they have no microbes inside them), mice treated with antibiotics as newborns (these which have significantly reduced gut bacteria levels), and mice with normal gut bacteria.   When exposed to peanut proteins,  the immune systems of both the sterile mice and the antibiotic treated mice exhibited much stronger antibody responses than the immune systems of mice with normal microbiota.

The scientists then investigated which types of gut bacteria, if any, could be given to mice to prevent them from developing peanut allergies. They found that when a class of bacteria called Clostridia was implanted into the mice's intestines, it could both prevent these mice from developing a peanut allergy and reverse any sensitivity they had to peanut allergens.  Clostridia are a highly diverse class of bacteria common in humans. Further investigations revealed that the presence of the Clostridia triggers the body's release of molecules that decrease the permeability of the gut lining and thus prevent antigens from entering the bloodstream where sensitization to allergens occurs.   

What to do:  These results highlight just how integral healthy gut bacteria are to the proper development and functioning of our immune systems.  Take care of your microbiota by consuming a healthy diet rich in fibers (these feed our natural bacteria) and cultured foods such as yogurt (these contain healthy bacteria), and by only using antibiotics when prescribed by a physician. 

Adapted from articles available at:

http://www.sciencedaily.com/releases/2014/08/140825152016.htm

http://www.uchospitals.edu/news/2014/20140825-nagler.html

http://www.healthline.com/health-news/can-gut-bacteria-protect-against-allergies-082514

Sources:

Stefka AT, Feehley T, Tripathi P et al.  Commensal bacteria protect against food allergen sensitization. Proceedings of the National Academy of Sciences, 2014; DOI: 10.1073/pnas.1412008111

Kalliomäki M, Isolauri E.  Role of intestinal flora in the development of allergy.  Current  Opinion in Allergy and Clinical Immunology. 2003 Feb;3(1):15-20.  Available at:  http://www.medscape.com/viewarticle/448473_5