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

The takeaway

Higher cannabis consumption was associated with reduced gut microbial diversity and lower Dialister abundance in older adults with HIV.

HIV care providers, researchers studying cannabis and the microbiome, patients with HIV using cannabis for symptom management.

14.4% Dialister reduction per 50-mg THC increase

What the researchers found

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).

Why it matters

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 numbers in context

63 participants. Mean age 59.4 years. 71.4% Black or Hispanic. Alpha diversity: beta = -0.062 per 50-mg THC/use-day (p = 0.038). Dialister: 14.4% reduction per 50-mg THC increase (q = 0.034). No significant beta diversity difference.

How the study worked

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.

What this study cannot tell us

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.

How to read the evidence

Preliminary: small cross-sectional study (N=63) with dose-response relationship but cannot establish causation.

When this study was published

2025 study

The bigger picture

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.

Questions still open

Does reduced Dialister abundance lead to worse mucosal barrier function in people with HIV? Is the microbiome effect reversible if cannabis use stops? Do the potential gut microbiome changes offset symptomatic benefits of cannabis for people with HIV?

Common questions

Does cannabis harm the gut in people with HIV?

This study found an association between higher cannabis use and reduced gut microbial diversity, but it cannot prove cannabis caused the change. The reduced Dialister levels are concerning because this bacterium helps maintain gut mucosal health.

Should people with HIV stop using cannabis based on this study?

This single small study cannot support that conclusion. It raises questions worth investigating further, but many people with HIV benefit from cannabis for symptom management and the overall risk-benefit picture remains unclear.

Read the original research

Cannabis use, microbial diversity and Dialister abundance in older adults with HIV: A cross-sectional study.

HIV medicine

View on PubMed ↗Publisher’s paper ↗

Citation

Porchia, Donald D; Wang, Yan; Zhou, Zhi; Chen, Mingkai; Porges, Eric C; Cohen, Ronald A; Ghare, Smita; Barve, Shirish; Cook, Robert L; Li, Zhigang. (2025). Cannabis use, microbial diversity and Dialister abundance in older adults with HIV: A cross-sectional study.. HIV medicine. https://doi.org/10.1111/hiv.70180