Trans-Resveratrol Supplementation and Endothelial Function during the Fasting and Postprandial Phase: A Randomized Placebo-Controlled Trial in Overweight and Slightly Obese Participants.

Studies on the effects of the long-term intake of trans-resveratrol on vascular function are conflicting. In addition, postprandial effects of long-term trans-resveratrol intake on endothelial function are not known. We therefore supplemented 45 overweight and slightly obese volunteers (25 men and 20 women) with a mean (±SD) age of 61 ± 7 years and body mass index of 28.3 ± 3.2 kg/m² in random order trans-resveratrol (2 × 75 mg/day) or placebo capsules for 4 weeks, separated by a washout period of at least 4 weeks. At the end of each intervention period, brachial artery flow-mediated vasodilation (FMD) was measured before and after meal consumption. Plasma biomarkers for endothelial function, inflammation, and glucose and lipid metabolism were also determined. Compared with the placebo, trans-resveratrol did not affect fasting FMD (2.9 ± 1.4% vs. 3.0 ± 1.9%; p = 0.69). After the postprandial test, changes in FMD (-0.7 ± 2.3% vs. 0.2 ± 2.6%; p = 0.13) were also not significantly different. Postprandial changes in biomarkers were also comparable. In conclusion, for overweight and slightly obese volunteers, a daily intake of 150 mg of trans-resveratrol for 4 weeks does not change plasma biomarkers of endothelial function or inflammation in the fasting state or postprandial phase.

Consuming a buttermilk drink containing lutein-enriched egg yolk daily for 1 year increased plasma lutein but did not affect serum lipid or lipoprotein concentrations in adults with early signs of age-related macular degeneration.

Dietary lutein intake is postulated to interfere with the development of age-related macular degeneration (AMD). Because egg yolk-derived lutein has a high bioavailability, long-term consumption of lutein-enriched eggs might be effective in preventing AMD development, but alternatively might increase cardiovascular disease risk. Here, we report the effect of 1-y daily consumption of a buttermilk drink containing 1.5 lutein-rich egg yolks on serum lipid and lipoprotein and plasma lutein concentrations. Additionally, subgroups that could potentially benefit the most from the intervention were identified. Men and women who had early signs of AMD in at least 1 eye, but were otherwise healthy, participated in a 1-y randomized, placebo-controlled parallel intervention trial. At the start of the study, 101 participants were included: 52 in the experimental (Egg) group and 49 in the control (Con) group. Final analyses were performed with 45 participants in the Egg group and 43 participants in the Con group. As expected, the increase in plasma lutein concentrations in the Egg group was 83% higher than that in the Con group (P < 0.001). Changes in serum total, HDL, and LDL cholesterol, as well as the ratio of total cholesterol to HDL cholesterol, were not different between the 2 groups. Interestingly, participants classified as cholesterol absorbers had higher serum HDL cholesterol concentrations than participants classified as cholesterol synthesizers or participants with average campesterol-to-lathosterol ratios (P < 0.05) at baseline. In addition, cholesterol absorbers had a 229% higher increase in plasma lutein concentrations than participants who were classified as having an average campesterol-to-lathosterol ratio upon consumption of the lutein-enriched egg yolk drink (P < 0.05). Moreover, the change in serum HDL cholesterol upon consumption was significantly different between these 3 groups (P < 0.05). We suggest that cholesterol absorbers particularly might benefit from the lutein-enriched buttermilk drink. This study was registered at clinicaltrials.gov as NCT00902408.