Impact of a short-term Mediterranean diet intervention on plasma metabolites: a pilot study

Background Dietary habits significantly influence the risks of type 2 diabetes and cardiovascular disease. Through metabolomics, we've previously measured plasma metabolites to gauge dietary quality, introducing a healthy dietary metabolic signature (HDMS) linked to a decreased risk of future type 2 diabetes and coronary artery disease. Objectives To assess the impact of a 6-day dietary intervention on plasma metabolites and the HDMS. Methods Fifty-nine Swedish participants (71% women, mean age 69 years) underwent a 6-day Mediterranean diet (MD) intervention in Italy's Cilento region. All meals, crafted from local recipes and ingredients, were provided. Metabolite profiling pre- and post-intervention was conducted with a UHPLC-QTOF. Alterations in metabolite levels and the HDMS were examined using paired T-test. Results The MD intervention notably enhanced the HDMS across participants (mean increase: 1.3 standard deviations (SD), 95% CI 1.1-1.4, p = 6E-25). Out of 109 metabolites, 66 exhibited significant alterations (fdr adjusted p < 0.05). Among the 10 most significant changes, increases were observed in several diet related metabolites such as pipecolate, hippurate, caffeine, homostachydrine, acylcarnitine C11:0, acetylornithine, beta-carotene and 7-methylguanine. The most significant decreases manifested in piperine and 3-methylhistidine. Conclusions The HDMS, which is linked to a healthy diet and inversely associated with cardiometabolic disease, was significantly improved by the 6-day Mediterranean diet intervention. Notably, metabolite markers previously shown to be indicative of the intake of vegetables, fruits, grains, and legumes increased, while markers previously associated with red meat consumption decreased. These findings highlight the potential of short-term dietary interventions to induce significant changes in plasma metabolite profiles.