Department of Nutrition, Harvard TH Chan School of Public Health, Boston, MA, USA.
Division of Preventive Medicine, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA.
Am J Clin Nutr. 2020 Dec 10;112(6):1448-1455. doi: 10.1093/ajcn/nqaa225.
Trimethylamine-N-oxide (TMAO) is a compound that is present in seafood and produced through human gut microbial metabolism of its precursors. Previous studies have suggested that elevated TMAO concentrations are associated with an increased risk of cardiovascular events. However, the association between diet and TMAO concentrations in free-living adult populations has not been adequately described.
The objective of this study was to identify dietary predictors of plasma TMAO concentrations.
TMAO concentrations were assessed in 2 fasting plasma samples collected 6 mo apart among 620 healthy men. Short-term and long-term dietary intakes were assessed during the same time-frame of blood collections via repeated 7-d dietary records (7DDRs) and a semiquantitative food-frequency questionnaire (SFFQ), respectively. We grouped individual food items into 21 groups and regressed against averaged TMAO concentrations. We also assessed the association between dietary scores and TMAO concentrations.
In models adjusted for demographic characteristics and mutually adjusted for food groups, SFFQ-assessments of fish and egg intakes were significantly associated with increased TMAO concentration (β = 0.082; 95% CI: 0.021, 0.14; P = 0.009 for fish; β = 0.065; 95% CI: 0.004, 0.13; P = 0.039 for egg). The positive association between fish consumption and TMAO concentration was replicated in the 7DDR-assessments (β = 0.12; 95% CI: 0.060, 0.18; P < 0.001). There was no association between red meat intake and TMAO concentrations. The unhealthful plant-based diet index (uPDI) was inversely associated (β = -0.013; 95% CI: -0.021, -0.005; P = 0.001) and healthy dietary scores were positively correlated with TMAO concentration.
TMAO concentration was significantly associated with fish intake, but not with red meat consumption. uPDI, an unhealthy dietary pattern, was inversely related to TMAO concentration. As such, this study suggests that in free-living populations, higher circulating concentrations of TMAO cannot simply be interpreted as a marker of unhealthy food intake or an unhealthy dietary pattern.
三甲胺 N-氧化物（TMAO）是一种存在于海鲜中的化合物，通过人体肠道微生物对其前体的代谢产生。先前的研究表明，TMAO 浓度升高与心血管事件的风险增加有关。然而，在自由生活的成年人群中，饮食与 TMAO 浓度之间的关联尚未得到充分描述。
本研究旨在确定血浆 TMAO 浓度的饮食预测因素。
在 620 名健康男性中，分别在相隔 6 个月的两次空腹血浆样本中评估 TMAO 浓度。在同一采血时间段内，通过重复的 7 天饮食记录（7DDR）和半定量食物频率问卷（SFFQ）分别评估短期和长期饮食摄入情况。我们将个体食物分为 21 组，并将其与平均 TMAO 浓度进行回归。我们还评估了饮食评分与 TMAO 浓度之间的关联。
在调整了人口统计学特征并相互调整了食物组的模型中，SFFQ 评估的鱼类和蛋类摄入量与 TMAO 浓度的增加显著相关（β=0.082；95%CI：0.021，0.14；P=0.009 对于鱼类；β=0.065；95%CI：0.004，0.13；P=0.039 对于蛋）。鱼类摄入与 TMAO 浓度之间的正相关关系在 7DDR 评估中得到了复制（β=0.12；95%CI：0.060，0.18；P<0.001）。红肉类摄入量与 TMAO 浓度之间没有关联。不健康的植物性饮食指数（uPDI）呈负相关（β=-0.013；95%CI：-0.021，-0.005；P=0.001），健康饮食评分与 TMAO 浓度呈正相关。
TMAO 浓度与鱼类摄入显著相关，但与红肉类摄入无关。uPDI，一种不健康的饮食模式，与 TMAO 浓度呈负相关。因此，本研究表明，在自由生活的人群中，循环中 TMAO 浓度的升高不能简单地解释为不健康的饮食摄入或不健康的饮食模式的标志物。
