Nutrition Notes

The Latest on Allergic Response and Gut Microbial Composition

The body’s response to allergens is a complex process that involves immune and inflammatory pathways. It often manifests as conditions such as allergic rhinitis, atopic dermatitis, and food allergies, and is estimated to affect more than 20% of the general population

The incidence of pathologies associated with the allergic response is on the rise. Some researchers have proposed a link between gut dysbiosis and allergic diseases. This is due to the important role the gut microbiome plays in the development of the immune system. Studies have shown that gut microbiota can influence certain aspects of the immune system and inflammatory responses. For example, a meta-analysis involving data from over 340,000 individuals reported that antibiotic use in children under 2 years old was associated with a higher risk of developing certain allergic diseases later in life, including food allergies, allergic rhinitis, asthma, and atopic dermatitis.

Recent clinical and preclinical research suggests that certain probiotics may support a healthy allergic response. A review article by Cukrowska and colleagues explored the role of different species within the Bifidobacterium genus in the presence of allergy in studies focused on infancy. In the early stages of life, the dominance of Bifidobacterium is thought to facilitate the development of certain aspects of the immune system related to the allergic response. Study conclusions indicate that the species Bifidobacterium breve in particular may support a healthy allergic response

One animal study included in the review by Cukrowska and colleagues explored the effects of the administration of Bifidobacterium breve M-16V with certain prebiotic molecules on a murine population. The study reported a protective effect against an acute allergic skin response and other signs of allergy. Cytokine analysis was performed and an intestinal Th1/Th2 balance was reported to be the underlying cause for this protective response. 

Another review explored the role of Lactobacillus in support of a healthy allergic response. One included study involving supplementation with Lactobacillus acidophilus L-92 reported significant alleviation of nasal symptoms. Another study reported 33% fewer episodes of rhinitis in the presence of supplementation with Lactobacillus. Other species of Lactobacillus were shown to modulate the presence of Th2 cytokines interleukin (IL)-4 and IL-5. In addition, L. paracasei was shown in laboratory studies to induce IL-12 and inhibit IL-4. IL-12 is associated with Th1 activity and IL-4 with Th2; Lactobacillus may therefore help balance Th1/Th2 cytokine levels.

Additionally, clinical studies indicate that the presence of Bifidobacterium longum and certain Prevotella species during pregnancy may influence certain qualities related to the development of food allergies during childhood. The administration of probiotics such as Lactobacillus rhamosus has been correlated with a higher level of achieved tolerance to non-IgE cow’s milk allergy in some infant studies. Improvements in colic and symptoms related to skin or food allergies were observed in children following the administration of Lactobacillus reuteri. In adult populations, decreases in eczema severity have been observed following the administration of certain probiotic strains. 

More research is needed, particularly in the clinical setting with larger treatment populations and with more varied microbiome considerations. However, research indicates a link between gut microbial health and a healthy response to certain allergens. Evidence also suggests that certain microbiome therapeutics may help support aspects of immune health. 

By Cory Ambrose, ND, MAT