Alteration of Plasma Lipidomic Profile by a Nordic and a Vegetarian Diet

Objectives: This study aims to investigate the effect of a Nordic (ND) and a Vegetarian diet (VD) on the fasting plasma lipidomic profile in adults with metabolic syndrome (MetS) traits. Methods: In a randomized-controlled trial in parallel-group design, 136 adults with MetS traits followed a six-week isocaloric ND or VD intervention or stayed on their habitual diet (control group). In the ND, dietary lipids originated primarily from fatty fish, nuts, and rapeseed oil; while in the VD, olive oil, milk products, and seeds were the main source of lipids. Venous plasma samples were collected at baseline and endline after an overnight fast. Total lipid fractions were extracted from plasma with Bligh & Dyer method based on a solvent system consisting of chloroform/ methanol (1:5). Plasma lipidomic profile was analyzed by direct infusion mass spectrometry and univariate ANOVAs were used to test for differences within and between the three groups. Results: In total more than 300 lipid species and 17 lipid classes were identified. Changes in the concentration of ten lipid classes (all with the strongest reduction in the ND), average number of double bonds (DB) in eight classes and average chain lengths in five classes differed significantly between the three diet groups. The ND led to significant lower concentrations of seven lipid classes, including classes associated with energy metabolism such as acylcarnitines and triacylglycerols (all p< 0.03), and total lipid levels (p=0.004) at endline. The average number of DB increased in five lipid classes (all p≤0.03) and the average chain lengths increased in three classes (all p< 0.001) after the ND. In the VD group, levels of two lipid classes (ether-linked phosphatidylcholines and ether-linked phosphatidylethanolamines), the average number of DB in three classes and the average chain lengths in two classes decreased (all p≤0.03). Conclusions: The ND and VD intervention significantly affected the plasma lipidome in adults with MetS traits. These results indicate that a mid-term dietary intervention has the potential to modulate plasma lipidomic profile, while especially the ND had a favorable impact. Considering this cohort is at high cardiometabolic risk, the results point towards risk-reducing potential of the ND. Funding Sources: The research was funded by the German Federal Ministry of Education and Research.