Definition:

Choline is a vitamin-like essential nutrient and a methyl donor involved in many physiological processes, including normal metabolism and transport of lipids, methylation reactions, and neurotransmitter synthesis.

• Choline deficiency causes abnormal deposition of fat in the liver, which results in a condition called nonalcoholic fatty liver disease. In some people, choline deficiency causes muscle damage. Genetic variants, sex, and hormonal status influence individual requirements and thus the susceptibility to choline deficiency-induced fatty liver disease.
• The recommended adequate intake (AI) of choline for Americans and Canadians is different across age groups and sex. For adults, the recommended intake is 425 milligrams (mg)/day for women and 550 mg/day for men. Dietary intake recommendations increase during pregnancy to 450 mg/day and lactation to 550 mg/day. The vast majority of people living in the United States have dietary intakes below the AI.
• Choline is involved in the regulation of homocysteine concentration in the blood through its metabolite betaine. There is currently no convincing evidence that high choline intakes could benefit cardiovascular health by lowering blood homocysteine. Moreover, elevated blood concentrations of trimethylamine N-oxide (TMAO), generated from choline, have been associated with an increased risk of cardiovascular events in some observational studies.
• The need for choline is probably increased during pregnancy. Case-control studies examining the relationship between maternal choline status and risk of neural tube defects have given inconsistent results. It is not yet known whether periconceptional choline supplementation could confer protection against neural tube defects.
• Choline is synthesized by humans from methionine and serine, and it is also present in the diet. Choline is the precursor for the neurotransmitter, acetylcholine.
• Animal studies have shown that choline is essential for optimal brain development and influences cognitive function in later life. However, more human studies are needed to assert that choline supplementation during pregnancy improves cognitive performance in the offspring or that choline supplementation helps prevent cognitive decline in older people.
• Choline may be useful for preventing and/or treating nonalcoholic fatty liver disease, hyperhomocysteinemia, blepharospasm, hyperthyroidism, and bipolar disorder.
• Choline has also been studied as a potential treatment to limit neurological damage in patients experiencing stroke or traumatic brain injury.
• De novo choline synthesis in humans is not sufficient to meet metabolic needs; therefore, choline intake from the diet is necessary. Good dietary sources of choline include eggs, meat, poultry, fish, cruciferous vegetables, peanuts, and dairy products.

Dosage and administration

• Excessive consumption of choline (≥7,500 mg) has been associated with blood pressure lowering, sweating, fishy body odor, and gastrointestinal side effects.
• Supplementation with 250–500 mg/day of choline may be useful for preventing a deficiency in people with low dietary choline intake. The most frequently used therapeutic dosages are 1–4 g/day, although larger amounts have been used to treat specific conditions.