Gut and Saliva Microbes May Hold Key to Managing Peanut Allergies

New research suggests that the severity of allergic reactions to peanuts may depend not only on the immune system, but too on the activity of bacteria in the mouth and gut. Scientists have discovered that certain microbes can break down peanut allergens, potentially reducing the intensity of allergic responses.

The Role of IgE and Anaphylaxis

Anaphylaxis, a severe and potentially life-threatening allergic reaction, is often triggered by foods like peanuts and is largely mediated by immunoglobulin E (IgE) antibodies ¹. When someone with a peanut allergy encounters peanut proteins, their body produces large amounts of IgE antibodies. These antibodies activate mast cells, leading to inflammation and symptoms like throat swelling and a drop in blood pressure.

Microbial Metabolism of Peanut Allergens

Researchers at the Autonomous University of Madrid in Spain and McMaster University in Canada have identified two types of bacteria – Rothia and Staphylococcus – that can degrade the proteins in peanuts responsible for triggering allergic reactions ¹. These bacteria, naturally found in human saliva and the modest intestine, can break down the immunodominant peanut allergens Ara h 1 and Ara h 2 ³. This process reduces the allergens’ ability to bind to IgE antibodies and activate mast cells.

Evidence from Laboratory and Clinical Studies

In vitro experiments demonstrated that Rothia and Staphylococcus species effectively broke down peanut allergens into fragments that caused less IgE binding and mast cell activation ³. Studies in mice colonized with Rothia showed reduced levels of peanut allergens in both the gut and bloodstream, and these mice experienced less severe anaphylactic reactions when exposed to peanuts ³.

Importantly, clinical analysis of patients with peanut allergies revealed a correlation between the abundance of peanut-degrading bacteria, including Rothia, and a higher threshold for allergic reactions ¹. This suggests that the composition of an individual’s gut and oral microbiota may influence the severity of their peanut allergy.

Gut Health and Peanut Allergy Risk

Research indicates that imbalances in gut bacteria (gut dysbiosis) and reduced microbial diversity may increase the risk of developing peanut allergies ².

Future Directions and Potential Therapies

These findings suggest that manipulating the gut and oral microbiota could be a potential therapeutic strategy for managing peanut allergies. Researchers are exploring the possibility of using probiotics or microbial enzyme supplementation to enhance the body’s ability to break down peanut allergens before they trigger an immune response. Though, further clinical trials are needed to determine the effectiveness of these approaches ¹.

Key Takeaways

• Specific bacteria in the mouth and gut can degrade peanut allergens.
• Rothia and Staphylococcus species have been identified as key allergen-degrading bacteria.
• A higher abundance of these bacteria may be associated with a reduced risk of severe allergic reactions.
• Modulating the gut microbiota could be a potential therapeutic strategy for peanut allergy management.

Reference: Sánchez-Martínez E et al. Microbial metabolism of food allergens determines the severity of IgE-mediated anaphylaxis. Cell Host Microbe. 2026; DOI:10.1016/j.chom.2026.02.013.