The effect of a tailored dietary intervention on serum biomarkers and faecal microbiome composition in people with HIV at risk of cardiovascular disease

Background: People with HIV (PWH) are at higher risk of cardiovascular disease (CVD) despite spontaneous or antiretroviral therapy-induced long-lasting suppressed viremia. Traditional and HIV-specific factors have been identified, but CVD incidence and mortality remain high. A microbiome is a community of germs living close to their human host, and bacterial dysbiosis is associated with atherosclerosis and chronic non-communicable disease development. Methods: We conducted a pilot study designed to analyze the effect of tailored diet intervention on body mass index (BMI), metabolic features and microbiota composition in PWH with suppressed HIV viremia (HIV RNA <50 copies/mL) under combination antiretroviral treatment. Biomarkers and parameters were measured at baseline and 6 months (M6) after. Results: Ten male participants were enrolled. The median age was 60.5 years (54–69) and the 10-year CV risk was 11.7% (7.2–21.2). CD4+ T lymphocyte count was 568 cells/mm3 (398–625). Approximately 75% of participants declared to be adherent to the given dietary recommendations. Participants showed reduced amounts of food intake (p = 0.022) and, specifically, of saturated fat (p = 0.007) and cholesterol (p = 0.011). At M6, most metabolic and inflammatory parameters remained stable. TMAO concentrations were higher at M6 than at baseline (157 vs. 129 ng/mL, p = 0.050). Microbiota alpha and beta diversity did not change over time: yet we observed a significant reduction of Firmicutes (p = 0.047) and an increase in Proteobacteria (p = 0.028) relative abundance at M6. Conclusions: In this pilot study assessing a tailored dietary intervention in high CV-risk PWH, we observed stable metabolic and inflammatory parameters and an unexpected increase in TMAO levels at 6 months. Microbiome composition was marginally affected, and active interventions are probably needed to elicit significant changes over time.