Associations of alcohol intake with gut microbiome: a prospective study in a predominantly low-income Black/African American population.

Background: Alcohol intake can alter gut microbiome, which may subsequently affect human health. However, limited population-based, prospective studies have investigated associations of habitual and recent alcohol intake with the gut microbiome, particularly among Black/African American individuals.

Objective: We examined the association of alcohol intake with gut microbiome in a predominantly low-income Black/African American population.

Methods: We investigated the dose- and type-specific associations of habitual and recent alcohol intake with the gut microbiome among 538 Black/African American adults (150 males and 388 females). Habitual and recent alcohol intakes were assessed at cohort baseline (2002-2009) and stool collection (2018-2021), respectively. Gut microbiome was profiled using shotgun metagenomic sequencing. Generalized linear models were employed to evaluate the associations between alcohol intakes and gut microbiome composition, with adjustments for sociodemographic characteristics, other lifestyle factors, and comorbidities. False discovery rate (FDR) <0.1 was considered statistically significant.

Results: The mean age at enrollment was 53.2 ± 7.7 y, with a mean interval of 13.8 y (range: 9.0-18.1 y) between baseline and stool sample collection. Recent alcohol intake was not significantly associated with microbial taxa abundance. However, habitual alcohol intake, both total amount and types of alcoholic beverages, showed significant associations with several microbial taxa abundance, primarily in males, including species within classes Clostridia, Bacilli, and Mahellia within Firmicutes. Specifically, total alcohol, beer, and red wine intakes were all inversely associated with genus MGYG-HGUT-02719 within class Clostridia (β = -2.26 to -0.09 per 1 drink/d increase). Red wine consumption was also inversely associated with the abundance of genera CAG-110, Oscillibacter, and Gemmiger within class Clostridia (β = -3.88 to -2.69), whereas positively associated with genus Absiella (β = 1.81) within class Bacilli. Most of these associations remained significant after additionally adjusting for BMI and baseline comorbidities.

Conclusions: We identified gut microbial taxa associated with habitual alcohol intake among Black/African American males, although the magnitudes of these associations were generally small. Further research is needed to determine if these bacteria modify alcohol-disease relationships.