Dr Carina Venter on the Gut Microbiome’s Role in Allergic Disease

Carina Venter, PhD, RD, allergy specialist dietitian and associate professor in pediatric allergy and immunology at Children's Hospital Colorado and the University of Colorado, discusses the gut microbiome’s complex relationship with our immune system and diet diversity’s potential role in allergic disease and food allergy­­–related outcomes.

She presented “Can the Microbiome be Manipulated to Prevent Food Allergy” during the symposium, “Solving the Puzzle of Food Allergy Prevention,” at this year’s American College of Allergy, Asthma & Immunology Annual Scientific Meeting.

Transcript

How does the gut microbiome contribute to the immune system’s reaction to certain allergens?

I think it's a very complex situation, which I'm trying to explain in a few simple sentences. In short, we know that the gut microbiome, particularly a more diverse gut microbiome, produces certain short-chain fatty acids; that's really been the aspects that I've been looking at. Clearly, there's many other metabolites that are produced by the gut microbiome. But in terms of the short-chain fatty acids, it seems that for now, butyrate is the most important fatty acid. Butyrate sort of has crosstalk with the immune system. It upregulates, or increases, the function of the T regulatory cells. The T regulatory cells just try and calm everything down again—if I can put it in simple terms. Really, in short, if we have a healthier or more diverse gut microbiome, which can help us to make more butyrate, perhaps we'll find that our immune system will be more tolerant to all the food allergens that we put into our gut.

How does the microbiome affect different types of atopic diseases?

That's a really good question: whether diet diversity affects all allergic disease outcomes in the same way. I’m first author of an [European Academy of Allergy and Clinical Immunology] EAACI position statement, where we looked at diversity in infancy vs asthma, allergic rhinitis, eczema, and food allergy outcomes. At this point in time, we see the biggest signal between diet diversity and food allergy. The data were a little bit more conflicting, particularly for eczema, where almost a certain number of papers indicated that increased diet diversity may prevent eczema later on in childhood vs no effect on eczema prevention. We even had a few papers that showed increased diet diversity was associated with increased eczema or atopic dermatitis outcomes.

I looked at my own data then to see, when we look a little bit more mechanistic and at IgE production, what happens, and clearly we showed that increased diet diversity by 6 months was associated with reduced sensitization to food allergens. But there was no effect seen on the aeroallergens. So perhaps there is some sort of specific interaction between diet diversity, its effect on the gut microbiome, and food allergen sensitization and food allergy outcomes specifically.