Impact d'un repas méditerranéen complet sur les fonctions métaboliques et endothéliales postprandiales en comparaison à un repas riche en acides gras saturés chez des hommes sains

Background The Westernization of lifestyles, notably dietary habits, seems to be largely responsible for the ongoing increase of incidence of cardiovascular diseases. The postprandial period, where vascular and metabolic homeostatic regulating processes are under pressure, is of considerable importance in the development or prevention of atherosclerosis and now represents the majority of waking hours. The understanding of the postprandial effects of meals of varying composition is therefore essential in our effort to prevent such diseases.    Objectives The main objective of this research project was to study the endothelial and metabolic responses to a mixed Mediterranean meal (MMM), since they are unknown. This project also aimed to evaluate the microvascular impact of such a meal and to characterize the composition of postprandial plasma fatty acids. These elements were also evaluated following a saturated fatty meal (HSFAM) for comparison.    Methods Twenty-eight (28) healthy men free of cardiovascular diseases and risk factors were randomly assigned one of two test meals. The MMM, consisting of fresh salmon and vegetables cooked in olive oil, contained 7.87g of SFA and 2.29g of omega- 3 fatty acids, while the HSFAM, consisting of a breakfast sandwich with egg, sausage and cheese contained 14.78g of SFA. Evaluations of endothelial function by brachial ultrasound (FMD), of microvascular function by near-infrared spectroscopy (NIRS) and of plasma fatty acids composition were done in the fasted and postprandial states.    Results Two subgroups of responders to the test meals emerged from this work. A first subgroup of subjects with high-normal fasting triglyceridemia (hnTG) experienced impairments of endothelial function following the HSFAM while a second subgroup of subjects with low-normal triglyceridemia (lnTG) did not experience any endothelial alterations following this meal. Interestingly, the MMM had no deleterious endothelial impact in any of those subgroups. Moreover, the hnTG subjects demonstrated greater postprandial triglyceridemic load (iAUC) that was in addition enriched with stearic acid after HSFAM and omega-3 PUFA following the MMM. Assessment of microvascular function revealed postprandial prolongation of post-ischemic reoxygenation only in hnTG subjects suggestive of alterations of capillary recruitment. These changes, which seemed to be more important after the HSFAM, could be partly responsible for its negative impact on FMD.    Conclusions This clinical trial demonstrates in innovative ways that a MMM has no deleterious effects on endothelial function irrespective of triglyceridemia in normal ranges. In addition, high but normal fasting triglyceride levels suggest metabolic and endothelial dysfunctions following nutritional challenges such as a HSFAM. Consumption of Mediterranean meals by healthy individuals with marginal triglyceride levels would be beneficial, perhaps even more so than for individuals with lower triglyceride levels, in preventing atherogenesis and cardiovascular diseases.

Keyphrases: Inflammation, Flow-mediated dilatation, Brachial echography, Microvascular function, Near infrared spectroscopy, Fasting triglyceridemia, Inflammation, Oxidative stress, Plasma fatty acid composition, Cardiovascular risk factors