Gut microbiota is a complex combination of microorganisms that caught the attention of scientists in the past several years. Being one of the largest organs in the human body, the gut is capable of performing more functions than just absorbing food and disposing its waste material.
In recent years, several studies have identified gut microbiota deeply involved in the normal functioning of the immunity and other systems in the human body. Immunity problems range from not having a proper defense to developing an exaggerated response to foreign substances, which is pretty much the best definition of allergy.
According to the WHO, probiotics are live microorganisms that can be administered through foods or supplements to regulate gut microbiota and confer a given health benefit. One of the benefits is to control diarrhea and normal gut motility, but that’s only the starting point. Probiotics can be used to control the appearance of allergy in children and adults, and there has been much research on the matter for the last several years.
It is well known that having a healthy gut microbiota helps to develop a normal immune system in children. Introducing probiotic strains in intestines with insufficient lymphoid tissue facilitates the development of healthy tissue that modulates the rest of the body. In the same way, probiotics can work on lymphoid cell receptors to help them differentiate and perform a more robust function.
Many probiotic strains have been tested to modulate the production of cytokines (an essential substance for inflammation and allergies).
For example, Bifidobacterium bifidum and Lactobacillus lactis can inhibit certain types of cytokines that trigger allergic reactions. In different studies, these strains were administered very early in life and reduced the risk of allergic reactions in 2-year-old children. Some studies even found out that pregnant woman who took probiotics had a lower chance of having children with eczema, a type of skin allergy.
Probiotics and peanut allergy
It is not an overstatement to say that probiotics can help us prevent and cure food allergies. For example, peanut allergy is a common cause of anaphylaxis, a severe food allergy that could quickly become deadly in a few minutes. Doctors have tried many types of strategies to induce desensitization to peanuts, and one of them is oral immunotherapy. It is an efficient way to help patients tolerate peanuts exposure for a given time, but after oral immunotherapy stops, the effects are not sustained. Similar to the allergic reaction during spring for Hay fever sufferers (Rhinitis)
After seeing that a combination of immunotherapy and bacterial adjuvants helped controlling allergic rhinitis, doctors tried a novel combination of oral immunotherapy and probiotics to cure peanut allergy. They used the strain Lactobacillus rhamnosus along with oral peanut immunotherapy and found out that over 80% of patients with peanut allergy were not responsive to the exposure to the allergen during treatment and afterward. An allergic substance called IgE was found to be lower, and the effects were sustained for over 5 weeks. Therefore, probiotics can be used as adjuvants for oral immunotherapy, and provides a long-lasting effect to the exposure of peanuts.
Morelli, L., & Capurso, L. (2012). FAO/WHO guidelines on probiotics: 10 years later. Journal of clinical gastroenterology, 46, S1-S2.
Hooper, L. V., Littman, D. R., & Macpherson, A. J. (2012). Interactions between the microbiota and the immune system. Science, 336(6086), 1268-1273.
Gorissen, D. M., Rutten, N. B., Oostermeijer, C. M., Niers, L. E., Hoekstra, M. O., Rijkers, G. T., & Van der Ent, C. K. (2014). Preventive effects of selected probiotic strains on the development of asthma and allergic rhinitis in childhood. The Panda study. Clin Exp Allergy, 44(11), 1431-3.
Niers, L. E., Timmerman, H. M., Rijkers, G. T., Bleek, G. V., Uden, N. V., Knol, E. F., … & Hoekstra, M. O. (2005). Identification of strong interleukin‐10 inducing lactic acid bacteria which down‐regulate T helper type 2 cytokines. Clinical & Experimental Allergy, 35(11), 1481-1489.