Whole egg consumption increases plasma choline and betaine without affecting TMAO levels or gut microbiome in overweight postmenopausal women.

As a crucial part of the symbiotic system, the gut microbiome is metabolically connected to many diseases and conditions, including cardiovascular diseases (CVD). Trimethylamine (TMA) is produced by gut bacteria from dietary choline, betaine, or L-carnitine, and is then converted in the liver to Trimethylamine N-oxide (TMAO), which in turn affects hepatic and intestinal lipid metabolism. Circulating TMAO is positively associated with CVD risk. Because eggs are rich in choline, it has been speculated that their consumption may increase plasma TMAO. In this study, we hypothesized that 2 eggs per day increases plasma TMAO level by altering gut microbiome composition in mildly hypercholesterolemic postmenopausal women. In this randomized, cross-over study, 20 overweight, postmenopausal women were given 2 whole eggs and the equivalent amount of yolk-free substitute as breakfast for 4 weeks, in randomized order, with a 4-week washout in between. Fasting blood draws and stool were collected at the beginning and end of each treatment period. Plasma TMAO, choline, betaine and other metabolites were analyzed using LC/MS, while gut microbiome composition was analyzed using 16S amplicon sequencing. Plasma choline and betaine were significantly increased after whole egg but not yolk-free substitute, however TMAO level was not significantly affected by treatments. Gut microbiome composition showed large inter-individual variability at baseline and in response to the treatments. The consumption of 2 eggs per day in overweight, postmenopausal mildly hypercholesterolemic women significantly increased plasma choline and betaine, but did not increase plasma TMAO or alter gut microbiome composition.

Effects of grape consumption on biomarkers of inflammation, endothelial function, and PBMC gene expression in obese subjects.

This study investigated effects of grape consumption on biomarkers of cardiovascular health in obese participants in both postprandial and chronic settings. Twenty obese adults participated in this randomized, placebo controlled, double-blinded crossover trial. Participants were randomized to consume 60 g freeze-dried polyphenol-rich whole grape powder (GP) or placebo (PBO) followed by high fat high carbohydrate (HFHC) meal challenge. Following acute challenge, participants consumed their respective treatment daily for 4 weeks to determine effects of chronic consumption. Consumption of GP with HFHC meal significantly increased nuclear factor (erythroid-derived 2)-like 2 (NRF2) expression in peripheral blood mononuclear cells (PBMC) at 3 h (p < 0.05) and decreased plasma endothelin-1 (ET-1) concentration at 5 h (p < 0.05) after meal challenge compared with PBO. Following 4 weeks of daily GP consumption, soluble vascular cell adhesion molecule 1 (sVCAM-1) plasma concentration increased compared with PBO (p < 0.05), however baseline values differed between treatments. In conclusion, GP consumption resulted in decreased vasoconstrictor ET-1 concentration and increased gene expression related to oxidative stress defense following HFHC meal. Except for increase in sVCAM-1 concentration, 4 weeks of chronic GP consumption had little effect on cardiovascular biomarkers measured in this study. This trial was registered: clinicaltrials.gov NCT01674231.