Cannabis Use Linked to Lower Gut Microbial Diversity in Older Adults with HIV

Among 63 older adults with HIV (mean age 59.4), higher cannabis consumption was significantly associated with reduced gut microbial alpha diversity (beta = -0.062 per 50-mg THC per use-day, p = 0.038). At the genus level, Dialister abundance showed a dose-dependent 14.4% reduction per 50-mg increase in THC per use-day (q = 0.034).

Cross-sectional analysis of 63 people with HIV (71.4% Black or Hispanic) from the MAPLE study and its microbiome substudy. Cannabis use was quantified using validated Timeline Followback. Fecal samples underwent 16S rRNA sequencing. Alpha diversity estimated by Shannon index, beta diversity by Bray-Curtis/PERMANOVA, genus-level abundance by IFAA method. Adjusted for age, sex, and education.

People with HIV frequently experience gut problems linked to disrupted microbiomes and weakened mucosal barriers. Many use cannabis to manage symptoms, but this study suggests cannabis may actually reduce beneficial gut microbial diversity, potentially worsening the very gut dysfunction it is used to treat.

The gut microbiome plays a critical role in HIV-related immune activation and inflammation. If cannabis reduces microbial diversity and depletes bacteria important for mucosal integrity, this could have implications for long-term gut health in people with HIV who use cannabis regularly, even if it provides short-term symptom relief.

Cross-sectional design cannot establish causation. Small sample size (N=63). Included participants with and without mild cognitive impairment. Self-reported cannabis use. 16S rRNA sequencing provides limited taxonomic resolution. Cannot determine whether reduced diversity preceded or followed cannabis use.