Choline
Choline is an essential nutrient (recognised by the IOM in 1998) required for phosphatidylcholine synthesis, acetylcholine production, methyl-group metabolism, and hepatic fat transport. About 90% of Americans consume less than the Adequate Intake — one of the largest population-scale nutrient shortfalls.
Daily Adequate Intake (AI)
- Adult men: 550 mg/day.
- Adult women: 425 mg/day.
- Pregnancy: 450 mg/day.
- Lactation: 550 mg/day.
- Tolerable Upper Intake Level: 3,500 mg/day — above this, hypotension, sweating, and fishy body odour occur.
Brain and fetal neurodevelopment
Choline is critical for fetal brain development — it's the precursor to acetylcholine and to phosphatidylcholine (the main membrane phospholipid). Meta-analyses of maternal choline supplementation trials show improved infant visual memory and attention. Prenatal vitamins have historically under-supplied choline (many contain 0 mg or < 100 mg); this is changing but check the label.
Non-alcoholic fatty liver disease
Choline is required for hepatic export of triglycerides as VLDL. Deficiency causes fatty liver even in the absence of alcohol. Observational studies link low choline intake with NAFLD prevalence. Supplementation trials are small but favourable for improving hepatic steatosis.
Sources
- Beef liver (3 oz): 356 mg — highest single food source
- Egg yolk (1 large): 147 mg
- Beef top round (3 oz): 117 mg
- Chicken breast (3 oz): 72 mg
- Fish, cod (3 oz): 71 mg
- Soybeans (½ cup): 107 mg
- Wheat germ (1 oz): 51 mg
- Milk (1 cup): 43 mg
- Peanuts (1 oz): 24 mg
Two eggs a day gets you to ~50–70% of the AI. Vegetarians and vegans who avoid eggs often fall well short and are candidates for supplementation.
Supplementation
- Choline bitartrate — cheapest; 41% choline by weight.
- Phosphatidylcholine — from lecithin; 13% choline; used clinically for NAFLD.
- Alpha-GPC — 40% choline; crosses the blood-brain barrier better; marketed for cognition.
- CDP-choline (citicoline) — supports cognition after stroke; used clinically in some countries.
- Standard supplemental dose: 300–500 mg/day if diet is low.
TMAO and cardiovascular concerns
Gut bacteria convert some dietary choline to trimethylamine, which the liver oxidises to TMAO. Elevated TMAO has been associated with cardiovascular risk in observational studies. However, egg and choline intake do not increase cardiovascular events in the overall body of RCT and cohort evidence. The TMAO concern remains a research topic rather than a reason to limit choline below the AI.