Investigation on the Effect of Carnitine Supplement on Gut Microbiota and TMAO Production Capacity

Recent studies have established plasma trimethylamine N-oxide (TMAO) levels as a strong, independent risk factor for cardiovascular disease. TMAO is produced by the interaction between gut microflora and ingested L-carnitine from food. Research indicates that both plasma TMAO concentration and the TMAO production capacity of gut microbiota in vegetarians are significantly lower than in omnivores, likely due to the reduced L-carnitine intake in vegetarian diets. This study aims to explore the impact of L-carnitine supplementation on the TMAO production capacity of human gut microbiota and to identify TMAO-producing bacteria within the gut microflora. The study plans to recruit both omnivore and vegetarian volunteers to undergo a one-month L-carnitine supplementation, followed by an evaluation of changes in TMAO production using an oral L-carnitine challenge test, along with gut microbiota assessment. TMAO concentration will be measured using LC-MS/MS, and gut microbiome analysis will be conducted through shotgun metagenome sequencing. Bioinformatic analysis may reveal potential TMAO-producing bacteria. Understanding the changes in TMAO production and gut microbiota composition post-L-carnitine supplementation may enhance our knowledge of the interplay between L-carnitine supplements, TMAO, and gut microflora.

Inclusion criteria

• Healthy subjects aged 20 to 65 years old
• no usage of antibiotics within one month
• no use of carnitine supplement within one month

Exclusion criteria

• having serious GI disorder
• medical history of myasthenia gravis
• history of diabetes,
• history of hyperparathyroidism,
• history of chronic kidney disease
• history of epilepsy
• history of severe anemia