In June 2016 Cell Reports a well-respected science journal published a fascinating paper on the connection between short chain fatty acids and associated nutrient and immune function that collectively reduced food allergy risk and response in their mice population.
For over 20 years (at the time of writing this) I have been describing the need for a ‘threshold therapy’ approach to the effective manipulation of the common mucosal immune system, in particular the recruitment of metabolic by products derived from food metabolism and microbiome functionality – as well as the specific replacement or supraphysiological supplementation of retinoids or their precursor families, vitamin D and enhancement of SigA are important aspects of this collective approach. Each of the interventions are modest in application and very low in risk, but the collective threshold crossing effect can assist the immune system in its effective maturation and maintainence of tolerance. This can be difficult to demonstrate in studies and as such much of the supportive data requires cross professional communication and data digging. This neat study helps to add credibility to the multiple point intervention through the manipulation of a subset of dendritic cells to favour a regulatory inducing phenotyope. I look forward to seeing how this approach is escalated into human trials in the coming years.
The incidence of food allergies in western countries has increased dramatically in recent decades. Tolerance to food antigens relies on mucosal CD103(+) dendritic cells (DCs), which promote differentiation of regulatory T (Treg) cells.
We show that high-fiber feeding in mice improved oral tolerance and protected from food allergy. High-fiber feeding reshaped gut microbial ecology and increased the release of short-chain fatty acids (SCFAs), particularly acetate and butyrate.
High-fiber feeding enhanced oral tolerance and protected against food allergy by enhancing retinal dehydrogenase activity in CD103(+) DC. This protection depended on vitamin A in the diet.
This feeding regimen also boosted IgA production and enhanced T follicular helper and mucosal germinal center responses.
Mice lacking GPR43 or GPR109A, receptors for SCFAs, showed exacerbated food allergy and fewer CD103(+) DCs. Dietary elements, including fiber and vitamin A, therefore regulate numerous protective pathways in the gastrointestinal tract, necessary for immune non-responsiveness to food antigens.
 Tan J, McKenzie C, Vuillermin PJ, Goverse G, Vinuesa CG, Mebius RE, Macia L, Mackay CR. Dietary Fiber and Bacterial SCFA Enhance Oral Tolerance and Protect against Food Allergy through Diverse Cellular Pathways. Cell Rep. 2016 Jun 21;15(12):2809-24. View Full Paper