Gut microbiota composition in adolescents with ADHD: associations with fatty acid and micronutrient intakes

Gut microbiome alterations have been reported in attention-deficit/hyperactivity disorder (ADHD), yet evidence in adolescents and links to diet and symptoms are limited. This study investigated gut microbiota composition and associations with ADHD symptoms and nutrient intakes in Australian adolescents.

This case-control study involved 39 adolescents aged 13-18 years with clinician-confirmed ADHD (n = 18) and healthy controls (n = 21). Gut microbiota were profiled using full-length 16S rRNA sequencing (PacBio HiFi). Alpha and beta diversity, the Firmicutes/Bacteroidota ratio, and relative abundances were compared between controls and ADHD. ADHD subtype (combined and inattentive) differences were also explored. Associations between taxa, selected energy-adjusted nutrient intakes, and ADHD symptom severity were assessed.

No group differences were observed in alpha or beta diversity or the Firmicutes/Bacteroidota ratio. Nominal relative abundance differences in ADHD included enrichment of Peptostreptococcales (p = .039), Coriobacteriaceae (p = .039), Collinsella (p = .045), Gemmiger (p = .038), and an unclassified Subdoligranulum species (p = .039), and reduction of Eubacterium F/Eubacterium xylanophilum (p = .040). Compared to inattentive ADHD, combined ADHD had lower abundance of Bacteroides and Parabacteroides species. The strongest associations were found between Peptostreptococcales and omega-3s (positive). Folate, beta-carotene, vitamin D, magnesium, added sugars, and monounsaturated fat were also nominally associated with taxa. No taxa-symptom correlations were significant.

Adolescents with ADHD exhibited several nominal relative abundance differences in gut microbiota. Associations between taxa and specific nutrient intakes highlight potential relevance of nutrition-microbiome interactions in ADHD, and warrant additional research.