# Gut Microbiome Mediates the Causal Link Between Autism Spectrum Disorder and Dietary Preferences: A Mendelian Randomization Study

## TL;DR

People with autism spectrum disorder have distinct dietary preferences, possibly influenced by gut microbes, suggesting new treatment possibilities.

## Contribution

This study identifies gut microbiota as a mediator of dietary preferences in autism using Mendelian randomization.

## Key findings

- ASD individuals prefer high-fat/salt and energy-dense foods, with lower fruit intake.
- Reduced Turicibacter, Streptococcus, and Lachnospiraceae NK4A136 are causally linked to ASD.
- Gut microbiota depletion mediates ASD-associated dietary preferences.

## Abstract

Autism spectrum disorder (ASD) frequently co-occurs with malnutrition and gut dysbiosis, yet the underlying mechanisms remain poorly understood. Herein, this cross-sectional study first profiles dietary intake differences using dietary records from 210,874 participants (ASD = 232; non-ASD = 210,642; median age = 56.18) from the UK Biobank (UKB). Second, a bi-directional Mendelian Randomization (MR) approach serves to dissect relationships between ASD genetic susceptibility and dietary preferences by leveraging genome-wide association metadata from the iPSYCH-PGC (ASD) and UKB (dietary intake/food-liking traits). The same strategy is implemented to identify ASD-associated gut microbial species. Mediation analyses further assess the role of gut microbiota in the association between ASD and dietary preferences. Subjects with ASD exhibit higher consumption of cheese, processed meat, and oily fish, alongside lower intake of fruits, and demonstrate a preference for high-fat/salt and energy-dense foods. Additionally, the depletion of Turicibacter, Streptococcus, and Lachnospiraceae NK4A136 was causally related with ASD (all false discovery rate < 0.05; β = −0.15, β = −0.10, β = −0.093, respectively), which significantly mediates the ASD-associated elevated preference for high-fat/salt foods. In conclusion, ASD is associated with specific dietary preferences, likely mediated via gut microbiota, highlighting the future potential of gut microbiome-based therapeutics to modify eating disorders for ASD.