Allergy associations with the adult fecal microbiota: Analysis of the American Gut Project

Abstract

BackgroundAlteration of the gut microbial population (dysbiosis) may increase the risk for allergies and other conditions. This study sought to clarify the relationship of dysbiosis with allergies in adults.MethodsPublicly available American Gut Project questionnaire and fecal 16S rRNA sequence data were analyzed. Fecal microbiota richness (number of observed species) and composition (UniFrac) were used to compare adults with versus without allergy to foods (peanuts, tree nuts, shellfish, other) and non-foods (drug, bee sting, dander, asthma, seasonal, eczema). Logistic and Poisson regression models adjusted for potential confounders. Odds ratios and 95% confidence intervals (CI) were calculated for lowest vs highest richness tertile. Taxonomy associations considered 122 non-redundant taxa (of 2379 total taxa) with ≥ 0.1% mean abundance.ResultsSelf-reported allergy prevalence among the 1879 participants (mean age, 45.5 years; 46.9% male) was 81.5%, ranging from 2.5% for peanuts to 40.5% for seasonal. Fecal microbiota richness was markedly lower with total allergies (P = 10− 9) and five particular allergies (P ≤ 10− 4). Richness odds ratios were 1.7 (CI 1.3–2.2) with seasonal, 1.8 (CI 1.3–2.5) with drug, and 7.8 (CI 2.3–26.5) with peanut allergy. These allergic participants also had markedly altered microbial community composition (unweighted UniFrac, P = 10− 4 to 10− 7). Total food and non-food allergies were significantly associated with 7 and 9 altered taxa, respectively. The dysbiosis was most marked with nut and seasonal allergies, driven by higher Bacteroidales and reduced Clostridiales taxa.InterpretationAmerican adults with allergies, especially to nuts and seasonal pollen, have low diversity, reduced Clostridiales, and increased Bacteroidales in their gut microbiota. This dysbiosis might be targeted to improve treatment or prevention of allergy.

The microbiome in allergic disease: Current understanding and future opportunities—2017 PRACTALL document of the American Academy of Allergy, Asthma & Immunology and the European Academy of Allergy and Clinical Immunology

“…Reduced microbial richness and increased Bacteroides were observed in subjects with self-reported peanut or tree nut allergy compared with those not reporting these allergies. 90 Although differences in the implicated taxa reported in this study versus the milk allergy studies might have been due to the specific food allergy targeted, additional explanations include this study’s focus on adults (vs children) and its use of self-reported food allergy, which is prone to reporting bias.…”

The infant gut bacterial microbiota and risk of pediatric asthma and allergic diseases

“…48,49 The findings from these two cross-sectional studies raise the interesting question of whether the differences found in adults are a cause or an effect of allergies and asthma. As with adult GI bacterial consortia, inter-personal differences in GI microbial communities are evident in infants, particularly in rate and stability of communities colonizing neonates.…”

Microbiome and food allergy

“…Hua et al recently reported findings from the publically available American Gut Project [19]. Of 1879 participants (primarily adult, mean age 45 years), 2.5% self-reported allergy to peanuts, 3.2% to tree nuts, 2.6% to shellfish, and 9.1% to other foods.…”