CARDIOVASCULAR PREVENTION THROUGH THE MODULATION OF GUT MICROBIOTA: A DIETARY INTERVENTION TRIAL

Background. There is growing interest in understanding how diet can modulate the gut microbiota (GM), including its possible association with disease states. Objective. To compare in a group of subjects in primary prevention for cardiovascular disease (CVD) the effects of Mediterranean (MD) and Vegetarian (VD) dietary patterns on the composition of the gut microbiota and on the production of short-chain fatty acids (SCFAs). Material and Methods. Twenty-three clinically healthy subjects (16 F; mean age: 58.6 ± 9.8 years) were randomly assigned to isocaloric MD or VD diets lasting 3- months each and then crossed. Anthropometric measurements, body composition, blood and fecal samples were obtained from each participant at the beginning and at the end of each intervention phase. Results. In the evaluated 23 subjects, a 3-month dietary intervention did not produce a diversity in GM composition at higher ranks (family and above), neither between nor within the MD and VD. Anyway, the two short-term dietary interventions have produced changes in GM composition at genus level. In detail, MD determined a significant change in the abundance of 3 genera (Enterorhabdus, Lachnoclostridium, Parabacteroides) while VD determined a significant change in the abundance of 4 genera (Anaerostipes, Clostridium sensu stricto, Odoribacter and Streptococcus). The comparison of the mean variation of each SCFA (post-pre diet) between MD and VD showed an opposite trend for acetic, butyric and propionic acid; in particular, MD led to a significant increase (10%) whereas a decrease (-28%) of propionate was found during VD. The variations of SCFAs were differently correlated with inflammatory cytokines such as VEGF, MCP-1, Interleukin (IL-)-17, IP-10 and IL-12, during the two dietary interventions. In addition, correlation analyses showed a potential relationship - modulated by the two diets - between changes of genera and changes of clinical and biochemical parameters. Conclusions. The present study showed that a short-term intervention with MD or VD induces no major changes in the GM taxonomic structure, suggesting that a diet must be protracted over longer periods to scratch the GM’s resilience. The variations of SCFAs during the dietary interventions and the correlation analysis support, however, their role in modulating the inflammatory response, thus mediating the anti- inflammatory and protective properties of MD.