Featured article in the August, 2016 Issue of Nutrition Research Update
Trimethylamine-N-oxide (TMAO) has been linked by some researchers to the development and progression of heart disease. TMAO is produced in the liver from trimethylamine, a by-product of microbial metabolism of the nutrients choline and carnitine. Eggs and beef contain choline and carnitine and as such, have been brought into the discussion about TMAO.
Fish intake has been shown to lower risk of cardiovascular disease. However, fish contains naturally high levels of trimethylamine, which should presumably result in higher concentrations of TMAO. To test this hypothesis, Dr. Marie Caudill and colleagues at Cornell University conducted a crossover feeding trial in 40 young men in which subjects were provided with meals containing fish, eggs, beef or a fruit control. Circulating and urinary TMAO were measured during the postprandial period.
Fish intake resulted in the highest levels of TMAO, 50 times that compared to eggs or beef.
Fecal samples were also collected to characterize populations of bacteria within the gut. Men that produced the highest levels of TMAO were found to have higher levels of Firmicutes and Bacteroidetes, suggesting that differences in the gut microbiome influences TMAO production.
Additional research is needed to better understand these relationships and how they translate to human health. Whether TMAO causes heart disease or is merely a biomarker of differences in the gut microbiome or another underlying factor remains to be determined.
Click here for more information describing this research from Cornell University.
Cho, C. E., Taesuwan, S., Malysheva, O. V., Bender, E., Tulchinsky, N. F., Yan, J., Sutter, J. L. and Caudill, M. A. (2016), Trimethylamine-N-oxide (TMAO) response to animal source foods varies among healthy young men and is influenced by their gut microbiota composition: A randomized controlled trial. Mol. Nutr. Food Res.. doi:10.1002/mnfr.201600324
This study was supported in part by the Egg Nutrition Center