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.

中文翻译：

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食用全蛋会增加血浆胆碱和甜菜碱，而不会影响绝经后超重女性的 TMAO 水平或肠道微生物群

作为共生系统的重要组成部分，肠道微生物群在代谢上与许多疾病和病症有关，包括心血管疾病 (CVD)。三甲胺 (TMA) 由肠道细菌从膳食胆碱、甜菜碱或左旋肉碱中产生，然后在肝脏中转化为三甲胺 N-氧化物 (TMAO)，进而影响肝脏和肠道的脂质代谢。循环中的 TMAO 与 CVD 风险呈正相关。由于鸡蛋富含胆碱，有人推测它们的食用可能会增加血浆 TMAO。在这项研究中，我们假设每天 2 个鸡蛋通过改变轻度高胆固醇血症绝经后妇女的肠道微生物组组成来增加血浆 TMAO 水平。在这项随机、交叉研究中，20 名超重者，绝经后妇女在 4 周内按随机顺序服用 2 个全蛋和等量的无蛋黄替代品作为早餐，中间间隔 4 周。在每个治疗期的开始和结束时收集空腹抽血和粪便。使用 LC/MS 分析血浆 TMAO、胆碱、甜菜碱和其他代谢物，而使用 16S 扩增子测序分析肠道微生物组组成。全蛋而非无蛋黄替代品后血浆胆碱和甜菜碱显着增加，但TMAO水平不受处理的显着影响。肠道微生物组组成在基线和对治疗的反应中显示出很大的个体差异。超重者每天吃2个鸡蛋，