Who Found Choline, and How Ox Bile Became an Essential Nutrient Story
Choline had a name for 136 years before the Institute of Medicine made it officially essential in 1998. Adolph Strecker named it from bile in 1862, and the story runs from neurine in the brain to citicoline.
Choline had a name for 136 years before the Institute of Medicine (IOM) made it officially essential in 1998. The history of choline starts in 1862, when Adolph Strecker reported that heating lecithin from bile produced a new nitrogen compound, and he named it choline. The same 1998 report also set intake levels for the eight B vitamins. ## Two names for one molecule Three years later, Oscar Liebreich identified a substance called neurine in the brain. After a period of confusion, neurine and choline turned out to be the same molecule, and the molecule kept the name choline. [Zeisel's 2012 history](https://doi.org/10.1159/000343120) lays out the sequence. Bile and brain, one molecule. ## The liver was the clue Charles Best, working at the University of Toronto in the 1930s, showed that choline prevented fatty liver in dogs and rats. Human evidence took longer. According to PubMed, a [2001 placebo-controlled trial](https://doi.org/10.1177/0148607101025005260) enrolled 15 patients (10 men and 5 women) who got at least 80 percent of their nutrition intravenously at home. Eight stayed on their usual feeding. Seven added 2 grams of choline chloride for 24 weeks. Liver density on CT scans was significantly higher in the choline group by week 4. When supplementation stopped, the scans showed the fat coming back. The authors wrote that the data suggest choline is a required nutrient for long-term home parenteral nutrition patients. ## How the body uses choline, and where citicoline fits NIH's Office of Dietary Supplements (ODS) says the body needs choline to make phosphatidylcholine, and that choline supplies methyl groups for many steps in metabolism. In 1954, Eugene Kennedy described the cytidine pathway that moves choline into phosphatidylcholine. Theodore Gobley had described lecithin in 1850 and named it after the Greek word for egg yolk. Lecithin was later characterized as phosphatidylcholine. Kennedy and Weiss published their 1956 paper, "[The function of cytidine coenzymes in the biosynthesis of phospholipides](https://pubmed.ncbi.nlm.nih.gov/13366993/)," in the Journal of Biological Chemistry. A second route came in 1960, when Jon Bremer and David Greenberg identified the phosphatidylethanolamine-N-methyltransferase pathway. Choline also became part of acetylcholine, a neurotransmitter, a role established by Otto Loewi and Henry Dale. That is where citicoline comes in. A [2022 citicoline review](https://doi.org/10.33588/rn.75s05.2022311) carries the MEDLINE heading Cytidine Diphosphate Choline, the chemical name for CDP-choline (cytidine diphosphocholine). Our [citicoline monograph](/ingredients/citicoline) covers the supplement itself. The [Cognizin citicoline research article](/research/cognizin-citicoline-neuropharmacology) covers the neuropharmacology work, and our [brain health guide](/health/brain-health-focus-complete-guide) covers the wider topic. ## Official status arrived in 1998 The IOM's 1998 Dietary Reference Intakes report covered choline alongside thiamin, riboflavin, niacin, vitamin B6, folate, vitamin B12, pantothenic acid and biotin. [ODS](https://ods.od.nih.gov/factsheets/Choline-HealthProfessional/) lists that report as its source. Zeisel and da Costa put the milestone plainly in their [2009 review](https://doi.org/10.1111/j.1753-4887.2009.00246.x): choline was officially recognized as an essential nutrient by the IOM in 1998. Adult adequate intakes, as ODS lists them, are 550 mg a day for men and 425 mg a day for women aged 19 and older. Pregnancy is set at 450 mg and lactation at 550 mg. ODS calls these adequate intakes rather than recommended allowances because the data were not enough to set an estimated average requirement. The adult upper limit is 3,500 mg a day, and ODS ties that limit to amounts linked with low blood pressure and fishy body odor. ODS also says the body makes some choline, mostly in the liver, but not enough to meet needs. Frank deficiency is very rare in healthy men and nonpregnant women, possibly because of that internal supply. The B vitamins in that same report have their own origin stories. Two are already on this site: the [vitamin B12 history, from liver cure to cobalamin](/blog/history/history-of-vitamin-b12-from-liver-cure-to-cobalamin) and the [folate history, from Lucy Wills to fortified bread](/blog/history/history-of-folate-from-lucy-wills-to-fortified-bread). ## Where choline is on the plate The ODS food table lists 356 mg of choline in 3 ounces of pan-fried beef liver and 147 mg in one hard-boiled large egg. Zeisel and da Costa say eggs and meats are rich sources in the North American diet, with up to 430 mg per 100 grams. ODS adds that cruciferous vegetables and certain beans are also rich in choline, and it lists nuts, seeds and whole grains as other sources. The 2009 review also found that mean intakes for older children, men, women and pregnant women sit far below the adequate intake. That gap is why the intake numbers matter in practice. **Bottom line.** Choline's official status dates to 1998. If you want a number, use the adult adequate intakes of 550 mg a day for men and 425 mg for women, check what your usual meals supply, and treat 3,500 mg a day as the adult upper limit. ## Questions people ask ### Who first isolated choline, and from what source? Adolph Strecker reported it in 1862. He heated lecithin taken from bile, and that produced a new nitrogen compound, which he named choline. Three years later, Oscar Liebreich identified neurine in the brain, and after some confusion the two turned out to be one molecule. Later work showed that lecithin itself is phosphatidylcholine, the molecule the body builds with choline. ### Why was choline not called a vitamin for so long? The sources checked for this page do not say why choline was not classed as a vitamin. What they do show is a timeline. The Institute of Medicine made choline officially essential in 1998. The body makes some of its own, mostly in the liver, and ODS says that supply is possibly why frank deficiency is rare in healthy men and nonpregnant women. ### When did choline become a recognized essential nutrient? The Institute of Medicine officially recognized choline as an essential nutrient in 1998, in the Dietary Reference Intakes report that also covered the B vitamins. Zeisel's [2012 history](https://doi.org/10.1159/000343120) says the importance of choline for human health was determined in the 1990s through controlled feeding studies in humans. A 2001 trial in patients on long-term home parenteral nutrition was titled "proof of a human choline requirement." ### Which foods are the richest sources of choline? The ODS food table lists 356 mg of choline in 3 ounces of pan-fried beef liver and 147 mg in one hard-boiled large egg. Zeisel and da Costa put eggs and meats at up to 430 mg per 100 grams in the North American diet. ODS also calls cruciferous vegetables and certain beans rich in choline, and it lists nuts, seeds and whole grains as other sources. ### How does choline relate to the citicoline story? Kennedy's 1954 pathway moved choline into phosphatidylcholine through a cytidine-linked form, which Zeisel's history calls the cytidine diphosphocholine pathway. A 2022 citicoline review carries the MEDLINE heading Cytidine Diphosphate Choline, the chemical name for CDP-choline. So the supplement and the pathway share a molecule. Our citicoline monograph covers the supplement itself, and the Cognizin citicoline research article covers the neuropharmacology work. ### Why did early choline research focus on liver fat? Charles Best's 1930s work at the University of Toronto showed that choline prevented fatty liver in dogs and rats. The 2001 human trial used the same organ as its target, measuring liver density on CT scans in patients on intravenous feeding. ODS says the adult intake standards are based on preventing liver damage, measured by a blood enzyme called alanine aminotransferase (ALT). ### How much choline do adults need per day? ODS lists adequate intakes of 550 mg a day for men aged 19 and older and 425 mg a day for women. Pregnancy is 450 mg and lactation is 550 mg. These are adequate intakes rather than measured requirements, because the data were not enough to set an estimated average requirement. The adult upper limit is 3,500 mg a day. Zeisel and da Costa also found that mean intakes fall far below the adequate intake for older children, men, women and pregnant women. The 1862 chemist started with bile. A hard-boiled egg gets you 147 mg by the ODS count, roughly a quarter of the adult adequate intake for men. **Next reads** - [Citicoline monograph](/ingredients/citicoline): what the supplement is, and the reference page this history leans on. - [Vitamin B12 history, from liver cure to cobalamin](/blog/history/history-of-vitamin-b12-from-liver-cure-to-cobalamin): the B vitamin story that sits beside choline in the 1998 report. ### Related reading - [The B vitamins from the same 1998 report](/blog/history/history-of-the-b-complex-from-one-factor-to-eight) - [Why the E was dropped from vitamine](/blog/history/history-of-the-word-vitamin-from-vitamine-to-the-dropped-e)