Choline: Adequate Intake, Food Sources, Pregnancy and the TMAO Question

Choline is an essential nutrient that sits beside the B vitamins without quite being one. The body makes some of its own, though not normally enough, so the rest has to come from food. ICMR-NIN's Nutrient Requirements for Indians (2020) sets no value for it, which is why Indian labels and diet charts rarely mention it. The figures in use are foreign: an adequate intake of 550 mg a day for men and 425 mg for women in the United States, and 400 mg for all adults from the European Food Safety Authority. This entry belongs to the vitamins section of the handbook.

What is choline, and is it a vitamin?

The papers read for this entry call choline an essential nutrient, not a vitamin; unlike a classic vitamin, the body can build some of it. The United States Institute of Medicine recognised it as essential in 1998 and published its reference intakes in the same volume as thiamine, riboflavin, folate and vitamin B12, which is how it came to be filed with the B group. The handbook follows that convention and places it here.

It does four jobs. It is needed to make acetylcholine, a chemical messenger in nerves. It is built into phosphatidylcholine, also called lecithin, which makes up more than half of the phospholipid in most cell membranes. It is needed to carry fat in lipoproteins. And through its product betaine it hands over methyl groups that turn homocysteine back into methionine, the point at which its work meets that of folate and B12, covered in the entry on folate and the entry on vitamin B12.

How much choline do you need in India?

There is no Indian figure to quote. ICMR-NIN's 2020 report gives allowances and average requirements for the B vitamins, vitamin C and the fat-soluble vitamins, and choline is not among them. The values below are therefore foreign and are labelled as such. Neither body could work out an average requirement, so both set an adequate intake, a weaker kind of figure. The American one rests on a single study in men of the amount that prevented a rise in a liver enzyme; the European one rests on average intakes in healthy Europeans and on the amount that restored depleted volunteers.

The two sets are close for pregnancy and breastfeeding and furthest apart for men, where the American value is 150 mg higher. The American figures were scaled to reference body weights of 76 kg for men and 59 kg for women, one more reason to read them as a guide and not a target. The United States also sets an upper limit of 3,500 mg a day for adults.

Which Indian foods supply choline?

Eggs, liver, fish and chicken supply the most, milk and soya a useful amount, and rice almost none. There is no Indian table to draw on: the Indian Food Composition Tables 2017 did not analyse choline, although the book's own history records that an earlier edition of the Indian tables listed choline for 60 foods. NNWA's nutrient rankings of Indian foods carry no choline list for that reason. The figures below are United States Department of Agriculture values as reproduced in two reviews. Treat them as a guide to scale.

Three things follow for an Indian plate. An egg is the densest everyday source: two in an egg bhurji give about 250 mg. For vegetarians the load is carried by milk and curd, pulses, soya, and vegetables such as cauliflower and peas, each adding a little; the milk and dairy tables and the pulses and legumes tables are the places to plan from. And a plate that is mostly rice supplies very little. The egg page and the fish and seafood tables show what else these foods provide.

American survey data show how much one food matters. In the national nutrition survey for 2009 to 2014, only 8.03 per cent of adults met the adequate intake. Adults who ate eggs averaged 525 mg a day against 294 mg among those who did not, and the authors judged it extremely difficult to reach the figure without eggs or a supplement. One of the authors consults for an egg industry body, which the paper declares.

Why does choline matter in pregnancy?

Because the baby draws heavily on the mother's supply. A review in Nutrition Reviews reports that the choline concentration in amniotic fluid is ten times that of the mother's blood, and that levels in the newborn are six to seven times adult levels. Breast milk is rich in choline too, so the drain continues after birth, and both sets of reference values rise accordingly.

The Indian data are sparse but pointed. In a four-country study, 245 women in rural Belagavi, Karnataka, were asked what they had eaten during the first trimester. Their median choline intake was 111 mg a day against the 450 mg reference, and more than 80 per cent of women at every site fell short. Their diet was rice, chapatti or jowar roti, milk tea, curd and pulses; fish was not part of it, and eggs were eaten very infrequently. NNWA's guide to the pregnancy diet in India covers the wider plate.

What extra choline achieves is less settled. One study found that women in the lowest quarter of choline intake had four times the risk of a baby with a neural tube defect compared with the highest quarter; that is an association, not proof. In a controlled feeding trial, 26 women in their third trimester ate either 480 or 930 mg a day, and infants of the higher group reacted faster on tests of processing speed up to 13 months of age. With 13 women in each arm, that is a promising finding and no basis for self-supplementing.

Too little: what deficiency looks like

Outright deficiency has been shown in feeding experiments, not in population surveys. In 1991, healthy men given a diet with no choline for three weeks saw plasma choline fall by about 30 per cent and a liver enzyme, alanine aminotransferase, climb steadily, while men given the same diet with choline did not. The American intake for men is built on this study.

A larger experiment in 57 adults refined the picture. Deprived of choline, 77 per cent of the men and 80 per cent of the postmenopausal women developed fatty liver or muscle damage, against 44 per cent of the premenopausal women, and the changes cleared when choline was returned. Oestrogen steps up the body's own production, which is the likely reason younger women were protected. No Indian survey of choline status was found for this entry, so how common a harmful shortfall is here remains unknown.

What does the TMAO research say about choline and the heart?

It raises a question that has not been answered, and it does not justify avoiding choline-rich foods. Gut bacteria convert some dietary choline to trimethylamine, which the liver turns into trimethylamine N-oxide, or TMAO. In a study of 4,007 patients undergoing coronary angiography, those in the highest quarter of blood TMAO had 2.54 times the risk of death, heart attack or stroke over three years compared with the lowest quarter. These were patients already under investigation for heart disease, and an association does not show that TMAO, or the choline behind it, was the cause.

Read together, the studies pull in different directions. Eating eggs does raise TMAO, modestly and very differently from one person to the next. Fish, which carries ready-made TMAO, raises it far more. And when researchers looked at what people ate, not at their blood, choline intake did not predict new heart disease, though the same review asked for more research on deaths from it. The careful reading is that blood TMAO also reflects gut bacteria and how the kidneys clear it. The cholesterol entry covers the other question people ask about eggs.

A worked example: a vegetarian day in pregnancy

This is an illustration, not a real person. Take a 27-year-old schoolteacher in Jaipur in her second trimester who is vegetarian and eats no eggs. The steps add up the foods in her day for which the tables above give a figure. Roti, dal and curd are left out because no value for them was read for this entry, so her true total is somewhat higher.

Do choline supplements have a place under FSSAI rules?

They are permitted, which is a different thing from being needed. FSSAI's health supplement regulations list choline, choline chloride, choline citrate and choline hydrogen tartrate in the schedule of amino acids and other nutrients that may be used. A pack sold as a health supplement must carry the words HEALTH SUPPLEMENT, declare the amount of each nutrient present, and print the advisory NOT FOR MEDICINAL USE. The same clause asks for amounts as a percentage of the ICMR allowance where applicable, and for choline there is no ICMR allowance to compare with.

Common myths and mistakes

The commonest mistake is to assume that a nutrient with no Indian allowance does not matter; the gap reflects missing Indian data, not a finding that needs are nil. The second is to treat the American 550 mg as a personal target, when it is an adequate intake drawn from one study in men of 76 kg. The third is to count on rice and roti: cooked rice carries about 2 mg per 100 g.

Too much choline: the upper limit and when to see a doctor

The United States sets an upper limit of 3,500 mg a day for adults, chosen to prevent a fall in blood pressure. It was derived from a report of low blood pressure at 7,500 mg a day, halved for safety and rounded down. Food does not approach it: no group in the American survey exceeded the limit. ICMR-NIN sets neither an allowance nor a limit.

Speak to your doctor before taking a choline supplement if you are pregnant or breastfeeding, have liver, kidney or heart disease, or take regular medicines. An unexplained rise in liver enzymes or a finding of fatty liver needs a medical assessment, not a nutrient bought over the counter; nothing in the deprivation experiments shows that choline treats liver disease in people who eat normally. Nothing on this page is advice about doses.

Learning this at NNWA

Essential nutrients, the limits of reference values and the planning of vegetarian plates are covered in the courses of NNWA, a private skill academy in Kolkata that teaches online in English and Hindi. The Diploma in Nutrition and the other courses train people to plan food for healthy clients and to refer pregnancy and medical cases to a doctor. None of them is a degree or a dietitian qualification.