Fasting triglyceridemia influences postprandial endothelial response to a single Mediterranean-type meal compared to a high-saturated fat meal

Abstract

BACKGROUND: Endothelial dysfunction is considered a precursor of atherosclerosis and is an independent predictor of car‐diovascular events. A high‐saturated fat meal (HFM) has been shown to induce postprandial endothelial dysfunction. However, no studies have evaluated the acute endothelial effect of a single mixed Mediterranean‐type meal (MMM). Our objective was to evaluate postprandial endothelial and metabolic function in response to a MMM in comparison to an isocaloric HFM and explore the role of baseline triglyceridemia. METHODS: In this crossover study, 28 healthy non‐smoking males were randomly assigned two isocaloric meals on two separate mornings. The MMM (885 kcal) consisted of fresh salmon, almonds and vegetables baked in olive oil providing 51% of total calories from fat (7.87g SFA and 2.29g of ome‐ga‐3, 2:1 DHA:EPA). The HFM (858 kcal) consisted of a McDonald's sausage, egg and cheese McMuffin and three hashbrowns providing 58% of total energy from fat (14.78g SFA and no omega‐3). Endothelial function was evaluated by brachial artery flow‐mediated dilation (FMD) after a 12‐hour fast (T0) and at two (T2) and four (T4) hours after consumption of the test meals. RESULTS: Postprandial FMD (T4) was significantly reduced by the HFM (‐2.5 +3.6%, p = 0.004), while it was not influenced by the MMM (‐1.21 +4.6%, ns). Postprandial insulin, AUC TG, TG/HDL and C/HDL were increased to a greater degree in response to the HFM relative to the MMM (meal x time p<0.002). Postprandial FMD (T4) during the HFM was significantly reduced (‐4.5+2.8%, p=0.002 vs baseline) among individuals with higher fasting TG levels (above the group median, 0.90 mmol/L) while it was unchanged among subjects with lower TG levels. Significantly higher postprandial AUC TG in individuals with higher fasting TG levels could explain this observation. CONCLUSION: A single MMM exerts less of a deleterious effect on postprandial endothelial function and metabolic profile than does a HFM. A single MMM could thus be less atherogenic. Moreover, subjects with higher fasting TG levels, but still bellow hypertriglyceridemia thresholds, could be at higher risk of endothelial injury following a single HFM. Analyses of oxidative stress and inflammatory markers are ongoing.