NIH ODS + Caudill pregnancy choline trial 2018

Vegan vs Vegetarian Choline: The Undersupplied Nutrient

Choline is the nutrient where the vegan vs vegetarian gap is largest after B12, because the densest natural source is the egg yolk. Vegetarians eating eggs hit the target without trying; vegans need to build choline into the day deliberately. The 2025 vegan nutrition literature has moved choline up the worry list, alongside B12, iodine, and omega-3.

The short answer. Adult women need 425 mg of choline per day (US IOM AI); adult men 550 mg; pregnancy 450 mg; lactation 550 mg. Vegetarians eating one or two eggs daily are usually replete. Vegans should eat soy, quinoa, broccoli, Brussels sprouts, and peanuts most days, and consider a 250 to 500 mg choline supplement, particularly during pregnancy.

Why choline is an essential nutrient

Choline was not formally classified as essential until 1998 when the US Institute of Medicine reviewed the evidence and set adequate intakes for adults and pregnant women. The body does synthesise some choline endogenously, in the liver, by methylating phosphatidylethanolamine using S-adenosyl methionine. The pathway provides perhaps 25 to 50% of needs in adults; the rest must come from the diet. Pregnancy and lactation increase requirements substantially, partly because choline crosses the placenta into the fetus at concentrations higher than maternal serum.

The four main biochemical roles of choline are: phosphatidylcholine, a major component of cell membranes and lipoprotein structures; acetylcholine, the parasympathetic and motor-neuron neurotransmitter; betaine via choline oxidation, a methyl donor that lowers homocysteine; and sphingomyelin, a myelin sheath component. Inadequate choline in adults can cause fatty liver (similar to non-alcoholic fatty liver disease) and elevated liver enzymes that resolve on supplementation. In pregnancy, low maternal choline status has been associated with neural tube defects (along with low folate) and with poorer cognitive outcomes in offspring in the Caudill 2018 trial.

The NIH Office of Dietary Supplements choline fact sheet sets out the full evidence base; the Vegan Society and Academy of Nutrition and Dietetics have both moved choline up their guidance lists in recent updates.

Choline per food, vegetarian and vegan sources compared

Food	Serving	Choline (mg)	Diet
Egg, large	1 (50 g)	147	Vegetarian
Egg yolk only	1 yolk (17 g)	115	Vegetarian
Cow milk (whole)	250 ml	38	Vegetarian
Cheddar cheese	30 g	5	Vegetarian
Plain yogurt	170 g	27	Vegetarian
Soy flour	100 g	120	Vegan
Tofu (firm)	100 g	28	Vegan
Edamame (cooked)	1 cup (155 g)	87	Vegan
Quinoa (cooked)	1 cup (185 g)	43	Vegan
Broccoli (cooked)	1 cup (156 g)	62	Vegan
Brussels sprouts (cooked)	1 cup (156 g)	63	Vegan
Cauliflower (cooked)	1 cup (124 g)	49	Vegan
Peanuts	30 g	24	Vegan
Almonds	30 g	15	Vegan
Potato (with skin, baked)	1 medium (170 g)	25	Vegan
Mushrooms (cooked)	1 cup (156 g)	27	Vegan
Choline bitartrate supplement	1 tablet	250 to 500	Vegan (verify)

Values from USDA FoodData Central. The choline per serving column makes the vegetarian advantage obvious: two eggs at breakfast supply 294 mg, more than half the female adult AI. A vegan needs to combine multiple foods through the day. A bowl of edamame, a quinoa lunch, broccoli at dinner, and a peanut snack reaches about 216 mg, which is half the AI; add a 250 mg supplement to clear the target.

Pregnancy: the case for proactive choline

The 2018 Cornell trial by Caudill and colleagues (FASEB J 2018; 32: 2172) randomised 26 pregnant women in their third trimester to 480 mg per day of choline (the AI) versus 930 mg per day. The infants born to the higher-choline arm showed improved performance on tests of sustained attention at one year of age compared to the AI-only arm. The trial was small and has not yet been replicated at scale, but it triggered substantial revisions to clinical pregnancy nutrition guidance.

The American Medical Association passed a resolution in 2017 calling for prenatal vitamins to include "evidence-based" levels of choline, which most US brands have begun to incorporate. UK prenatal vitamins have been slower to add choline; check labels carefully. A pregnant vegan eating one cup of edamame at lunch, one cup of broccoli at dinner, and a 250 mg supplement clears the 450 mg AI without difficulty. A pregnant vegan relying on diet alone needs more deliberate effort.

The pre-pregnancy and early pregnancy folate-plus-choline interaction is important. Both nutrients are involved in one-carbon metabolism and methylation, both are needed for neural tube closure, and the demand on the methylation pathway is highest in the first trimester. Folate supplementation alone is established advice; adequate choline is the second leg of the same stool.

The TMAO question

Choline in the diet can be metabolised by gut bacteria into trimethylamine (TMA), which the liver converts to trimethylamine-N-oxide (TMAO). High serum TMAO has been associated with cardiovascular risk in some prospective studies (Tang WHW et al., NEJM 2013 and follow-up). The early concern was that high choline intake might drive higher TMAO and therefore raise cardiovascular risk, which would complicate the pregnancy-choline story.

The subsequent evidence has moderated this picture. TMAO from dietary choline is variable and largely determined by gut microbiome composition. Vegans and vegetarians have lower baseline TMAO than omnivores even on identical choline doses, plausibly because their microbiomes have fewer of the TMA-producing bacteria. Recent reviews (Krueger 2023, Heianza 2023) suggest that dietary choline at AI levels is not a meaningful cardiovascular concern in plant-based eaters. Pregnant vegans should not avoid choline on TMAO grounds; the developmental benefit clearly outweighs the speculative cardiovascular cost.

Supplement choice. Most choline supplements are choline bitartrate (45% choline by weight, so a 1,000 mg tablet supplies 450 mg actual choline) or alpha-GPC (40% choline). Phosphatidylcholine is also available but is more expensive per mg of delivered choline. Confirm the supplement is vegan; some softgel capsules use gelatine. Look for tablets or vegan softgels (tapioca, carrageenan).

Frequently asked questions about choline

What is choline and why does it matter?

Choline is an essential nutrient first recognised as such by the US Institute of Medicine in 1998. It is required for cell membrane structure (phosphatidylcholine), neurotransmission (acetylcholine), lipid transport (VLDL assembly), and methyl-group metabolism. Inadequate choline can cause non-alcoholic fatty liver disease, raised liver enzymes, and during pregnancy may affect fetal neural tube and cognitive development. The body can synthesise small amounts of choline endogenously via phosphatidylethanolamine N-methyltransferase, but synthesis is insufficient to meet needs, hence the essential status.

What are the choline RDAs?

The US IOM sets adequate intakes rather than RDAs because deficiency data is limited. AIs are 550 mg per day for adult men, 425 mg for adult women, 450 mg during pregnancy, and 550 mg during lactation. The European Food Safety Authority sets adequate intakes of 400 mg for adult men and women, 480 mg in pregnancy, and 520 mg during lactation. The UK does not currently set a dietary reference value for choline. The tolerable upper intake from supplements is 3,500 mg per day for adults (excess causes hypotension and a fishy body odour from trimethylamine metabolism).

Why are eggs so important for choline?

Egg yolks are one of the densest natural choline sources. A single large egg supplies around 147 mg of choline, predominantly as phosphatidylcholine in the yolk. Two eggs at breakfast clear over half the adult woman's AI in one go. Beef liver supplies 360 mg per 100 g but is rarely eaten. Cow milk supplies around 38 mg per 250 ml, useful but not dense. For lacto-ovo vegetarians eating one or two eggs a day, the choline picture is essentially solved. For vegans, the picture is more work.

What are the best plant choline sources?

Plant choline content is lower per serving than egg yolk but still adds up. Soy flour supplies around 120 mg per 100 g; tofu around 28 mg per 100 g; cooked quinoa about 43 mg per cup; broccoli about 62 mg per cup cooked; Brussels sprouts about 63 mg per cup cooked; peanuts about 24 mg per 30 g; potatoes about 25 mg per medium potato. Building 400 mg per day from these sources is achievable but requires deliberate planning. The Vegan Society recently added choline to its recommended-monitoring nutrients alongside B12 and iodine.

Should vegans take a choline supplement?

Choline supplements (typically choline bitartrate or alpha-GPC) are widely available at doses of 250 to 500 mg. They are reasonable as insurance for vegans who do not regularly eat soy, quinoa, broccoli, or peanuts. Pregnant vegans should pay particular attention because pregnancy AI is higher (450 mg) and adequate choline supports fetal cognitive development per the Caudill 2018 trial. Avoid sustained doses above 3,500 mg per day due to hypotension and trimethylamine body odour risk. Most prenatal vitamins do not include meaningful choline; check the label and consider a separate supplement if your food intake is low.

Is choline deficiency actually a problem in vegans?

Population data is limited because choline is not routinely measured in clinical practice. The published surveys (Wallace and Fulgoni 2017 in the US, Vennemann 2015 in the EU) suggest that around 90% of US adults of all diet patterns fall short of the choline AI. Vegans are likely to be at the lower end of this distribution because the densest natural sources (egg yolk, liver) are excluded. There are documented case reports of choline deficiency producing fatty liver in long-term vegans, though rare. The pragmatic working assumption: vegans should treat choline as a nutrient to actively include in the diet, similar to how they treat iodine.

Sources cited. NIH ODS Choline fact sheet for health professionals; Caudill MA et al. Maternal choline supplementation during the third trimester of pregnancy improves infant information processing speed: a randomized, double-blind, controlled feeding study, FASEB J 2018; 32: 2172-2180; Wallace TC, Fulgoni VL. Usual choline intakes are associated with egg and protein food consumption in the United States, Nutrients 2017; 9: 839; Institute of Medicine. Dietary Reference Intakes for Thiamin, Riboflavin, Niacin, Vitamin B6, Folate, Vitamin B12, Pantothenic Acid, Biotin, and Choline. National Academy Press 1998; EFSA Panel on Dietetic Products. Dietary reference values for choline, EFSA J 2016; 14: 4484; Krueger ES et al. The interactive relationship between gut microbiota and cardiovascular disease: TMAO in transit, Nutrients 2023; 15: 2056. All values as of May 2026.