Choline

Choline is an essential nutrient, but it is not a vitamin, a mineral or a typical phytonutrient. It is a small water-soluble molecule that every plant and animal cell needs to build its membranes. Your body also uses it to make acetylcholine, a messenger for memory, mood and muscle control. It also passes on methyl groups (small chemical tags) in metabolism, according to the NIH (the US National Institutes of Health).

The liver makes some choline, but not enough, so the rest has to come from food. About half of the choline Americans eat is phosphatidylcholine, which lecithin is rich in.

Eggs gave lecithin its name. In 1850 Theodore Gobley named it after the Greek word for egg yolk. In 1862 Adolph Strecker heated lecithin from bile and named the new chemical he found choline.

Eggs are still the top choline food in the USDA ranking below. One large egg holds 147 mg, which is 27% of the Daily Value (the daily amount used on US food labels).

Many people fall short of the official targets. In US survey data from 2009 to 2012, only 10.8% of people aged 2 and up reached the adequate intake for choline. An adequate intake is a target set when the data are too thin for a firm requirement. The NIH says about 90% to 95% of pregnant women eat less than it.

Outright deficiency is rare in healthy people, though. Read the targets with care too. The US value for men rests on one hospital study of 16 men, and the value for women was scaled from it. That is how EFSA, the EU’s food safety agency, describes it.

Health benefits of choline

• ★★★Adequate daily intakes set for adultsThe EU sets an adequate intake of 400 mg a day for adults. The US sets 550 mg for men and 425 mg for women, and the men’s value rests on one trial of 16 men.
• ★★★EU accepts claims for lipids, liver and homocysteineEFSA found a cause and effect link for normal lipid metabolism, normal liver function and normal homocysteine metabolism. A food needs at least 82.5 mg of choline per 100 g, per 100 ml or per portion to carry them.
• ★★Too little choline damaged liver and muscleIn 57 adults fed almost no choline, fatty liver or muscle damage hit 77% of men and 80% of postmenopausal women. This was within 42 days, and organ function returned to normal when choline was added back.
• ★★Pregnancy supplement did not help infant memoryIn 140 pregnant women, 750 mg a day of phosphatidylcholine did not improve infant memory or language at 10 and 12 months. They already ate about 360 mg of choline a day, and later effects were not tested.
• ★★Eating eggs did not clearly change blood TMAOTMAO is a compound that gut bacteria make from egg choline. Across 6 trials of eating eggs, blood TMAO, choline and betaine did not change clearly, and results were uncertain.

Foods high in choline

Eggs lead all three USDA rankings on this page. One large egg holds 147 mg, 27% of the 550 mg Daily Value, and eggs hold 294 mg per 100 g.

Shrimp comes second, with 115 mg in 3 oz and 135 mg per 100 g. Next per serving is chicken breast (92.8 mg in 4 oz), with soybeans and navy beans close behind. Per 100 g, chicken breast (82.1 mg) and flaxseeds (78.7 mg) follow shrimp. The ranking below has the full list.

Beef liver is not in our ranking, but the NIH fact sheet lists pan-fried beef liver at 356 mg in 3 oz. That is 65% of the Daily Value and more than two eggs. By that arithmetic, three large eggs give 441 mg, just above the 425 mg US adequate intake for women.

Per 100 kcal, low-calorie vegetables rank high: cauliflower gives 177 mg and endive 98.8 mg, against 205 mg for eggs.

How choline works

Most of the biochemistry below is well established. But the details come from reviews, cell work and animal studies rather than from trials of extra choline in people. Four ideas cover most of it. Choline is built into cell membranes, helps move fat out of the liver, passes on methyl groups and becomes the nerve messenger acetylcholine.

Gut bacteria add a fifth, less welcome route. Here is each one, and what has been seen in people.

It is built into cell membranes

Cells make phosphatidylcholine from choline, and this is the main fate of the choline they take in. Phosphatidylcholine is a major part of membranes, which is why the NIH says all plant and animal cells need choline. In mice, losing the enzymes that turn choline into phosphatidylcholine is so harmful that some knockouts die as embryos.

It helps carry fat out of the liver

The liver packs fat into particles called VLDL and sends them into the blood. That step needs phosphatidylcholine, so without enough choline, fat piles up in liver cells. Mice that cannot make their own phosphatidylcholine and are fed no choline lose the right balance of membrane fats and develop liver failure.

People show it too. In a feeding study, going without choline led to fatty liver or muscle damage in many volunteers. In patients fed by vein, added choline improved fatty liver signs.

It passes on methyl groups

Choline can be converted to betaine, and betaine can hand a methyl group to homocysteine, turning it back into methionine. This links choline to the folate pathway. When your diet is low in folate, the need for choline goes up, according to the NIH.

In one crossover trial, a high dose of choline lowered homocysteine in men. EFSA still says homocysteine cannot be used to set an intake target, because many other things influence it.

It becomes a nerve messenger

Nerves use choline to make acetylcholine. This is why choline gets so much attention for memory and brain development, but the human evidence is not settled. In 2011 EFSA did not support a claim for choline and cognitive function.

A 2015 review of 13 studies, as summarized by the NIH, found that supplements did not clearly improve thinking (cognition) in healthy adults. Studies in pregnancy are mixed, as the cards above show.

Gut bacteria turn some choline into TMAO

Choline that is not absorbed is left for gut bacteria, which turn it into trimethylamine (TMA). The liver converts TMA to TMAO. In mice, this route promoted atherosclerosis, and in a test in people, antibiotics lowered TMAO after an egg meal.

Seafood also contains TMAO directly. Water-soluble choline supplements raised TMAO in a small crossover study, but egg phosphatidylcholine did not.

What has been seen in people

The clearest result in people is about deficiency. In a feeding study of 57 adults, going without choline caused fatty liver or muscle damage in many. It reversed when choline was added back. Beyond that, the picture is mixed.

In pregnancy, one trial of 140 women found no gain in infant tests. Small feeding trials at 930 mg a day found faster reaction times and better attention. For the heart, cohort studies disagree, and trials of eggs found no change in TMAO. All of these are among the study cards above.

Is choline safe? Supplements, dose and interactions

Choline from food is not a concern for most people. The US sets a tolerable upper intake level, the most you should get each day, from food and supplements. It is 3,500 mg a day for adults and 3,000 mg for ages 14 to 18.

For children it is 2,000 mg for ages 9 to 13 and 1,000 mg for ages 1 to 8. The NIH says the upper level applies to pregnancy and breastfeeding too.

The IOM took 7.5 g a day as the lowest dose with adverse effects. Seven people with Alzheimer’s disease had low blood pressure with nausea and diarrhea at that dose. The IOM noted a fishy body odor at 8 to 20 g a day in other studies, and applied a safety factor of 2. We found no upper level in EFSA’s 2016 opinion, which only describes the US one.

• Doses and side effects. Supplements typically hold 10 to 250 mg of choline. The NIH lists a fishy body odor, vomiting, sweating, salivation, low blood pressure and liver toxicity at high intakes. In children given 500 mg a day for 9 months, the only side effect linked to choline was a fishy body odor. In pregnancy, 750 mg a day of phosphatidylcholine was well tolerated.
• Fishy odor and trimethylaminuria. People with two faulty copies of the FMO3 gene excrete trimethylamine in urine, breath and sweat, which smells like rotting fish. Management can include limiting choline-rich foods such as eggs and liver. The diet should still be planned so that choline intake meets recommendations, according to GeneReviews.
• Heart disease and TMAO. It is unsettled whether choline from food raises heart risk. Some cohorts found higher mortality with higher intake, and others found no link. The NIH says more research is needed.
• Pregnancy and medicines. The NIH says choline is not known to have clinically relevant drug interactions. It also says prenatal supplements usually contain little or no choline. Ask your doctor or dietitian before taking a supplement, particularly if you are pregnant or take regular medicines.

How to get more choline

• Best food. One large egg gives 147 mg, 27% of the Daily Value, and beef liver gives 356 mg in 3 oz, according to the NIH. Chicken breast (92.8 mg in 4 oz) and soybeans (81.7 mg per cup) are other good choices in our ranking.
• Food over pills. Supplements usually hold 10 to 250 mg, so one egg gives more than most. No studies have compared how well your body absorbs choline bitartrate, phosphatidylcholine and lecithin. Phosphatidylcholine from eggs did not raise TMAO in a six-man test.
• Eat enough folate. When your diet is low in folate, choline becomes the main source of methyl groups and the need for it rises. So a low-folate diet is a reason to pay closer attention to choline.

History of choline

The story starts in Paris. In 1850 Theodore Gobley described a substance he called lecithin, from the Greek for egg yolk. In 1862 Adolph Strecker found that heating lecithin from bile produced a new nitrogen-containing chemical, which he named choline.

Three years later Oscar Liebreich found a substance called neurine in the brain. It took time to show that neurine and choline were the same molecule.

The roles came one by one. Eugene Kennedy described the pathway that builds choline into phosphatidylcholine in 1954, and Jon Bremer and David Greenberg found a second route in 1960. Otto Loewi and Henry Dale established its part in the nerve messenger acetylcholine. In the 1930s Charles Best showed in Toronto that choline prevented fatty liver in dogs and rats.

Whether people need it in the diet took longer. In a hospital study in 1991, healthy men fed no choline for three weeks showed signs of early liver dysfunction. In 1998 the US Institute of Medicine set adequate intakes for choline, and in 2016 EFSA set 400 mg a day for adults. The EU listed health claims for choline in Regulation 432/2012.

Frequently asked questions about choline

What does choline do for the body?

Every cell uses choline to build membranes, and your body also uses it to make acetylcholine and to pass on methyl groups. The clearest human evidence is about deficiency. In a feeding study, 77% of men and 80% of postmenopausal women fed almost no choline developed fatty liver or muscle damage.

The EU authorizes claims for liver function, lipid metabolism and homocysteine metabolism. Benefits of extra choline beyond that are unproven.

How much choline do you need a day?

The US adequate intake for ages 19 and up is 550 mg for men and 425 mg for women. It is 450 mg in pregnancy and 550 mg while breastfeeding. EFSA sets 400 mg for adults, 480 mg in pregnancy and 520 mg while breastfeeding. These are adequate intakes, not firm requirements, because the data were too thin to set averages. The NIH reports average US intakes of 402 mg for men and 278 mg for women in 2013 to 2014.

Which foods are highest in choline?

Eggs lead our USDA ranking, with 147 mg in one large egg and 294 mg per 100 g. Per serving, shrimp (115 mg in 3 oz) and chicken breast (92.8 mg in 4 oz) follow. Soybeans (81.7 mg per cup) and navy beans (81.4 mg per cup) come next. The NIH lists pan-fried beef liver at 356 mg in 3 oz, which is not in our ranking.

Does choline have side effects?

At food amounts, not for most people. The NIH says high intakes can cause a fishy body odor, vomiting, sweating, salivation, low blood pressure and liver toxicity. The US upper level is 3,500 mg a day for adults. In children given 500 mg a day for 9 months, the only side effect linked to choline was a fishy body odor. The NIH knows of no clinically relevant drug interactions.

Is choline important in pregnancy?

Needs rise: the US adequate intake is 450 mg and EFSA’s is 480 mg. The NIH says about 90% to 95% of pregnant women eat less than the US value. Evidence that extra choline helps the baby’s brain is mixed. A trial of 140 women taking 750 mg a day found no difference in infant tests. A small trial found faster reaction times with 930 mg than with 480 mg. For neural tube defects, one study linked low blood choline to higher odds and another found no difference. Ask your doctor, since prenatal supplements usually contain little or no choline.

Does choline raise TMAO and heart risk?

Gut bacteria turn some choline into TMA, which the liver turns into TMAO. In cohorts, high blood TMAO goes with more heart events; in one study the top fourth had 2.54 times the risk. Whether eating choline raises heart risk is unsettled. ARIC found no clear link (1.22 times the risk, which could be chance). A meta-analysis of 6 cohorts found 11% higher cardiovascular mortality per 100 mg. A meta-analysis of 6 trials found eggs did not change TMAO.

What is the difference between choline and lecithin?

Lecithin is a substance rich in phosphatidylcholine, and phosphatidylcholine is the main form of choline in food. So lecithin is a source of choline, not a separate nutrient. Supplements come as choline bitartrate, phosphatidylcholine or lecithin, and the NIH says no studies have compared how well your body absorbs them. In a six-man test, water-soluble forms raised TMAO quickly and egg phosphatidylcholine did not.

Can you get enough choline on a plant-based diet?

Animal foods are the richest sources, but plant foods contribute. The NIH lists roasted soybeans (½ cup) at 107 mg and a large baked potato at 57 mg. It lists canned kidney beans (½ cup) at 45 mg, cooked quinoa (1 cup) at 43 mg and boiled broccoli (½ cup) at 31 mg. Compare that with an adequate intake of 425 mg for women. We did not review studies of vegan diets, so we cannot say how many people on them reach the target.