The European food safety authority (EFSA) published an opinion regarding the use of L-carnitine L-tartrate, a source of L-carnitine, in foods for particular nutritional uses. Taking into account gastrointestinal symptoms, clinical chemistry, included markers of liver and kidney function, EFSA agreed on the following guideline values:
| EFSA assumes that an intake of 3 g of L-carnitine L-tartrate is safe. This is equivalent to a daily amount of L-carnitine of 2 g for adults, which is approximately 10-20 times what a person consumes on an average omnivorous diet. According to the EFSA, gastrointestinal pain may occur when L-carnitine is taken above this amount. However, the occurrence of this side effect varies and has only been demonstrated with consumption of 4-6 g/day. |
Certain nutrients, such as carnitine, phosphatidylcholine, and choline are particularly metabolized via gut microbiome metabolism to produce trimethylamine (TMA). TMA is absorbed in the intestine and converted in the liver by hepatic flavin-containing monooxygenases (FMOs) to trimethylamine N-oxide (TMAO), a proatherogenic and prothrombotic metabolite (intermediate of metabolism).Elevated levels of TMAO are associated with an increased risk of cardiovascular events.. Several studies have suggested that TMAO contributes to the promotion of cardiovascular risk by promoting the formation of atherosclerotic lesions.
