Investigation on the Effect of Carnitine Supplement on Gut Microbiota and TMAO Plasma Concentration

In this project, the investigators aim to investigate if daily carnitine supplementation could induce TMAO productivity of vegetarian gut microbiota and through which the TMAO producers might be disclosed.

Recently, plasma trimethylamine N-oxide (TMAO) level has been proved to be a strong and independent risk factor of cardiovascular disease. TMAO is formed through interaction between gut microflora and the ingested carnitine from food. Studies have shown that plasma TMAO concentration and TMAO productivity of gut microbiota in vegetarians are significantly lower than omnivores. This is probably due to a lack of carnitine in the diet of vegetarians. Therefore, it is worth investigating whether carnitine supplementation could induce TMAO productivity of human gut microbiota as well as to reveal TMAO producers from gut microflora. Therefore, the investigators plan to recruit 20 vegetarian and 10 omnivore volunteers to receive carnitine supplement for weeks, and study the change of plasma TMAO and gut microbiota. The plasma TMAO concentration will be measured by the LC-MS, and the gut microbiota composition will be analyzed by the next generation sequencing. Through bioinformatics analysis, the potential TMAO-producing bacteria might be discovered. The change of plasma TMAO level and gut microbiota composition after carnitine supplementation can provide more understanding on the relationship between carnitine supplement, TMAO and gut microflora.

Inclusion Criteria: no usage of antibiotics and carnitine supplement within one month Exclusion Criteria: serious GI disorder, myasthenia gravis, diabetes, hyperparathyroidism, chronic kidney disease, history of epilepsy, severe anemia

Wu WK, Chen CC, Liu PY, Panyod S, Liao BY, Chen PC, Kao HL, Kuo HC, Kuo CH, Chiu THT, Chen RA, Chuang HL, Huang YT, Zou HB, Hsu CC, Chang TY, Lin CL, Ho CT, Yu HT, Sheen LY, Wu MS. Identification of TMAO-producer phenotype and host-diet-gut dysbiosis by carnitine challenge test in human and germ-free mice. Gut. 2019 Aug;68(8):1439-1449. doi: 10.1136/gutjnl-2018-317155. Epub 2018 Oct 30.