Benefits
Pregnancy intake and infant brain development
In a controlled feeding trial, 26 women in their third trimester ate 930 or 480 mg of choline a day until delivery. Infants in the 930 mg group had faster average reaction times on information processing tests between 4 and 13 months of age. The study was small, and about 90 to 95% of pregnant women in the US eat less than the Adequate Intake.
Liver fat export and normal liver function
The liver needs choline, mainly as phosphatidylcholine, to carry fat out. In a controlled feeding study, 77% of men and 80% of postmenopausal women developed fatty liver or muscle damage on a very low choline diet, and function returned when choline was added back. This shows choline is needed for normal liver function, not that extra choline helps people who already get enough.
Acetylcholine production for memory and muscle control
Choline is needed to make acetylcholine, a nerve messenger involved in memory, mood and muscle control. Observational studies link higher choline intake or blood levels with better cognitive scores in older adults, but the NIH Office of Dietary Supplements notes that more research is needed before supplements can be said to help memory.
Homocysteine metabolism
Choline supplies methyl groups used in many steps of metabolism, and some researchers have suggested it may help lower blood homocysteine. However, several large observational studies found no link between choline intake and heart disease risk, and higher choline intake raises TMAO, a compound linked to heart disease risk.
Mechanism of action
Phosphatidylcholine for membranes and fat transport
The body uses choline to make phosphatidylcholine and sphingomyelin, phospholipids that build cell membranes. Phosphatidylcholine is also needed to transport fat out of the liver, which is why low choline intake leads to fat buildup in the liver.
Methyl group source
Choline is a source of methyl groups needed for many steps in metabolism. How much a person needs depends partly on intake of methionine, betaine and folate, as well as sex, pregnancy and common gene variants.
Acetylcholine synthesis
Choline is needed to produce acetylcholine, a neurotransmitter for memory, mood, muscle control and other brain and nervous system functions.
Clinical trials
Randomized, double-blind, controlled feeding trial: women entering the third trimester ate 480 or 930 mg of choline a day until delivery, and infants were tested at 4, 7, 10 and 13 months. Funded in part by the Egg Nutrition Center, the Beef Checkoff and the USDA (Caudill et al. 2018, FASEB Journal).
26 pregnant women (13 per group) and 24 of their infants.
Average reaction time across the four test ages was faster for infants whose mothers ate 930 mg a day than for those whose mothers ate 480 mg. Both groups ate at least the Adequate Intake of 450 mg. The sample was small, and the funders had no role in the analysis.
Inpatient controlled feeding study: 10 days on 550 mg choline per 70 kg a day, then under 50 mg per 70 kg a day for up to 42 days, with or without folic acid; liver fat measured by MRI (Fischer et al. 2007, American Journal of Clinical Nutrition).
57 healthy adults: 26 men, 16 premenopausal women and 15 postmenopausal women.
On the low choline diet, 77% of men and 80% of postmenopausal women developed fatty liver or muscle damage, versus 44% of premenopausal women. Organ function returned to normal when choline was added back. Six men showed these signs even at 550 mg per 70 kg a day. Folic acid did not change the response.