Editing Choline (section)

==Excess intake==
Excessive doses of choline can have adverse effects. Daily 8–20&nbsp;g doses of choline, for example, have been found to cause [[low blood pressure]], [[nausea]], [[diarrhea]] and [[Fish-odor disease|fish-like body odor]]. The odor is due to trimethylamine (TMA) formed by the gut microbes from the unabsorbed choline (see [[trimethylaminuria]]).<ref name=eu/>

The liver oxidizes TMA to trimethylamine ''N''-oxide (TMAO). Elevated levels of TMA and TMAO in the body have been linked to increased risk of [[atherosclerosis]] and mortality. Thus, excessive choline intake has been hypothetized to increase these risks in addition to [[carnitine]], which also is formed into TMA and TMAO by gut bacteria. However, choline intake has not been shown to increase the risk of dying from [[cardiovascular disease]]s.<ref name= "DiNicolantonio_2019" >{{cite journal | vauthors = DiNicolantonio JJ, McCarty M, OKeefe J | title = Association of moderately elevated trimethylamine ''N''-oxide with cardiovascular risk: is TMAO serving as a marker for hepatic insulin resistance | journal = Open Heart | volume = 6 | issue = 1 | pages = e000890 | date = 2019 | pmid = 30997120 | pmc = 6443140 | doi = 10.1136/openhrt-2018-000890 }}</ref> It is plausible that elevated TMA and TMAO levels are just a symptom of other underlying illnesses or genetic factors that predispose individuals for increased mortality. Such factors may have not been properly accounted for in certain studies observing TMA and TMAO level related mortality. Causality may be reverse or confounding and large choline intake might not increase mortality in humans. For example, [[kidney dysfunction]] predisposes for cardiovascular diseases, but can also decrease TMA and TMAO excretion.<ref>{{cite journal | vauthors = Jia J, Dou P, Gao M, Kong X, Li C, Liu Z, Huang T | title = Assessment of Causal Direction Between Gut Microbiota-Dependent Metabolites and Cardiometabolic Health: A Bidirectional Mendelian Randomization Analysis | journal = Diabetes | volume = 68 | issue = 9 | pages = 1747–1755 | date = September 2019 | pmid = 31167879 | doi = 10.2337/db19-0153 | doi-access = free }}</ref>