Plasma metabolites and the Planetary Health Diet – potential biomarkers for a sustainable diet

Abstract Background The EAT-Lancet Planetary Health Diet (PHD) was introduced to address the dual threats that current food production and consumption pose to human health and environmental sustainability. While adherence to the PHD has been associated with favorable health outcomes, such as lower body weight and improved cardiometabolic profiles, the underlying metabolomic mechanisms remain unclear. As metabolites may reflect the biological pathways of diet, we aimed to examine the plasma metabolites associated with the PHD. Methods In total, 4209 men and 5016 women (≥18 years) from the Finnish FinHealth 2017 and DILGOM 2007 studies were included. A validated food frequency questionnaire was used to assess the habitual diet. We developed an energy-standardized dietary index based on the PHD adapted for the Finnish food culture (score range 0 − 13 points). A high-throughput nuclear magnetic resonance (NMR) spectroscopy metabolomics platform (Nightingale Health Plc) with a panel of 158 metabolites was used to quantify plasma metabolite profile. Linear regression, adjusted for relevant confounders, with false discovery rate (FDR) p-values was used for statistical analyses. Results The mean PHD score for men was 3.4 (SD 1.3) and for women 4.1 (SD 1.4). Six beneficial metabolites (acetate, estimated degree of unsaturation of fatty acids, and several fatty acid ratios to total fatty acids (polyunsaturated fatty acids, docosahexaenoic acids, omega-3 fatty acids, and linoleic acids)) were positively associated and ratio of saturated fatty acids to total fatty acids was negatively associated with PHDS (FDR p < 0.05). Conclusions Higher diet quality was associated with a more favorable plasma fatty acid profile and higher concentrations of the short-chain fatty acid acetate. These associations may reflect improved dietary fat quality due to lower consumption of animal-based foods and increased fiber intake linked to greater adherence to the PHD. Key messages • A healthy and sustainable diet may improve health through several mechanisms, even with low adherence. • Understanding metabolomic mechanisms linked to better diet adherence may reveal novel targets for effective disease prevention.