Differential effects of Nordic and Vegetarian diets on lipid metabolism, gut microbiome and cardiometabolic risk factors: A multi-omic perspective from a randomized clinical intervention trial

BackgroundBeneficial effects of diets with predominance of plant-based foods as fruits, vegetables, whole grain and plant-protein and less animal-based foods, or so-called "plant-based" diets, on cardiometabolic risk have been reported. We aimed to examine the effects of two distinct plant-based diets on intermediate cardiometabolic risk factors, particularly lipid metabolism, while also considering the impact of the gut microbiome, genetic predisposition, and immune status on the metabolic response to a dietary change. MethodsIn this randomized, controlled dietary intervention trial, 120 obese adults (59 {+/-} 1 years, 70 females) consumed an isoenergetic Nordic (ND) or a lacto-ovo vegetarian diet (VD) or maintained their habitual diet (control group) for six weeks. At baseline and after the end of the trial, in-depth metabolic characterization was conducted, including measurement of incretins such as glucagon-like peptide 1 (GLP-1), postprandial lipids with lipidomic profiling, and microbiome analysis. Genetic makeup and peripheral immune system composition were characterized at baseline. ResultsND intervention beneficially altered lipid metabolism up to 15%. The largest changes were observed in participants with high genetic predisposition for hyperlipidemia, while lipid metabolism remained stable upon VD. The changes observed were associated with specific microbial signatures and pathways. GLP-1 levels remained stable during the study period. ConclusionThe metabolic response to a dietary change in obese adults is linked to the individual genetic risk, baseline microbiome composition, and immune phenotype, pointing towards a personalized nutritional approach in preventing cardiometabolic diseases.