Choline is an essential nutrient that plays a role in the synthesis of phospholipid membranes and is a source of methyl groups that are needed for many steps in metabolism. It’s also the precursor to the neurotransmitter acetylcholine. Choline has particular relevance for brain development, liver health, and skeletal muscle function. Choline is mostly found in animal foods such as eggs, milk, fish, chicken, and beef, but some plant foods also contain choline.[reference|url=https://pubmed.ncbi.nlm.nih.gov/30332744|title=Dietary Choline Intake: Current State of Knowledge Across the Life Cycle.|published=2018 Oct 16|authors=Wiedeman AM, Barr SI, Green TJ, Xu Z, Innis SM, Kitts DD|journal=Nutrients|]

Choline supplementation during pregnancy or early childhood has favorable effects on children’s brain function and neurodevelopment including memory, attention, and visual-spatial learning.[reference|url=https://pubmed.ncbi.nlm.nih.gov/36041182|title=Association between Maternal Choline, Fetal Brain Development, and Child Neurocognition: Systematic Review and Meta-Analysis of Human Studies.|published=2022 Dec 22|authors=Obeid R, Derbyshire E, Schön C|journal=Adv Nutr|] Choline supplementation among children with fetal alcohol spectrum disorder improves memory, nonverbal intelligence, visual-spatial skills, ADHD symptoms, executive function, and white matter microstructure.[reference|url=https://pubmed.ncbi.nlm.nih.gov/26447156|title=Choline supplementation in children with fetal alcohol spectrum disorders: a randomized, double-blind, placebo-controlled trial.|published=2015 Nov|authors=Wozniak JR, Fuglestad AJ, Eckerle JK, Fink BA, Hoecker HL, Boys CJ, Radke JP, Kroupina MG, Miller NC, Brearley AM, Zeisel SH, Georgieff MK|journal=Am J Clin Nutr|][reference|url=https://pubmed.ncbi.nlm.nih.gov/32164522|title=Four-year follow-up of a randomized controlled trial of choline for neurodevelopment in fetal alcohol spectrum disorder.|published=2020 Mar 12|authors=Wozniak JR, Fink BA, Fuglestad AJ, Eckerle JK, Boys CJ, Sandness KE, Radke JP, Miller NC, Lindgren C, Brearley AM, Zeisel SH, Georgieff MK|journal=J Neurodev Disord|][reference|url=https://pubmed.ncbi.nlm.nih.gov/36526961|title=Long-term follow-up of a randomized controlled trial of choline for neurodevelopment in fetal alcohol spectrum disorder: corpus callosum white matter microstructure and neurocognitive outcomes.|published=2022 Dec 16|authors=Gimbel BA, Anthony ME, Ernst AM, Roediger DJ, de Water E, Eckerle JK, Boys CJ, Radke JP, Mueller BA, Fuglestad AJ, Zeisel SH, Georgieff MK, Wozniak JR|journal=J Neurodev Disord|] These effects occur primarily when choline is supplemented before the age of 5.

Higher choline intakes have been associated with a lower risk for cardiovascular events and stroke, cognitive impairment, post-stroke depression,[reference|url=https://pubmed.ncbi.nlm.nih.gov/34611955|title=Circulating choline pathway nutrients and depression after ischemic stroke.|published=2022 Feb|authors=Miao M, Du J, Che B, Guo Y, Zhang J, Ju Z, Xu T, Zhong X, Zhang Y, Zhong C|journal=Eur J Neurol|] cardiovascular disease,[reference|url=https://pubmed.ncbi.nlm.nih.gov/37764819|title=Association between Dietary Choline Intake and Cardiovascular Diseases: National Health and Nutrition Examination Survey 2011-2016.|published=2023 Sep 18|authors=Zhou R, Yang M, Yue C, Shi Y, Tan Y, Zha L, Zhang J, Chen S|journal=Nutrients|] and dementia.[reference|url=https://pubmed.ncbi.nlm.nih.gov/31360988|title=Associations of dietary choline intake with risk of incident dementia and with cognitive performance: the Kuopio Ischaemic Heart Disease Risk Factor Study.|published=2019 Dec 1|authors=Ylilauri MPT, Voutilainen S, Lönnroos E, Virtanen HEK, Tuomainen TP, Salonen JT, Virtanen JK|journal=Am J Clin Nutr|] A higher intake of choline is also associated with lower levels of cardiometabolic risk factors.[reference|url=https://pubmed.ncbi.nlm.nih.gov/36124652|title=One-year longitudinal association between changes in dietary choline or betaine intake and cardiometabolic variables in the PREvención con DIeta MEDiterránea-Plus (PREDIMED-Plus) trial.|published=2022 Dec 19|authors=Díez-Ricote L, San-Cristobal R, Concejo MJ, Martínez-González MÁ, Corella D, Salas-Salvadó J, Goday A, Martínez JA, Alonso-Gómez ÁM, Wärnberg J, Vioque J, Romaguera D, López-Miranda J, Estruch R, Tinahones FJ, Lapetra J, Serra-Majem L, Bueno-Cavanillas A, Tur JA, Martín Sánchez V, Pintó X, Gaforio JJ, Matía-Martín P, Vidal J, Mas Fontao S, Ros E, Vázquez-Ruiz Z, Ortega-Azorín C, García-Gavilán JF, Malcampo M, Martínez-Urbistondo D, Tojal-Sierra L, García Rodríguez A, Gómez-Bellvert N, Chaplin A, García-Ríos A, Bernal-López RM, Santos-Lozano JM, Basterra-Gortari J, Sorlí JV, Murphy M, Gasulla G, Micó V, Salaverria-Lete I, Goñi Ochandorena E, Babio N, Herraiz X, Ordovás JM, Daimiel L|journal=Am J Clin Nutr|] Interestingly, a low choline intake may impair gains in strength and lean mass in response to exercise training[reference|url=https://pubmed.ncbi.nlm.nih.gov/37764658|title=The Effect of Choline and Resistance Training on Strength and Lean Mass in Older Adults.|published=2023-Sep-06|authors=Lee CW, Lee TV, Galvan E, Chen VCW, Bui S, Crouse SF, Fluckey JD, Smith SB, Riechman SE|journal=Nutrients|][reference|url=https://pubmed.ncbi.nlm.nih.gov/36629089|title=Low Intake of Choline Is Associated with Diminished Strength and Lean Mass Gains in Older Adults.|published=2023|authors=Lee CW, Galvan E, Lee TV, Chen VCW, Bui S, Crouse SF, Fluckey JD, Smith SB, Riechman SE|journal=J Frailty Aging|] and reduce cognitive function.[reference|url=https://pubmed.ncbi.nlm.nih.gov/31360988|title=Associations of dietary choline intake with risk of incident dementia and with cognitive performance: the Kuopio Ischaemic Heart Disease Risk Factor Study.|published=2019 Dec 1|authors=Ylilauri MPT, Voutilainen S, Lönnroos E, Virtanen HEK, Tuomainen TP, Salonen JT, Virtanen JK|journal=Am J Clin Nutr|]

High/excessive intakes of choline can result in some side effects, including a fishy body odor, vomiting, excessive sweating and salivation, low blood pressure (hypotension), and liver toxicity.[reference|url=https://ods.od.nih.gov/factsheets/Choline-HealthProfessional/|title=Choline: Fact Sheet for Health Professionals; USA: National Institutes of Health Office of Dietary Supplements; last updated 2 June 2022; cited April 2024|published=2018] In addition, choline consumption has been shown to increase the production of trimethylamine N-oxide (TMAO), which is associated with an increased risk of cardiovascular disease. However, some studies indicate that the amount of choline consumed in 3 eggs per day does not elevate plasma TMAO levels.[reference|url=https://pubmed.ncbi.nlm.nih.gov/29764315|title=Effects of Egg Consumption and Choline Supplementation on Plasma Choline and Trimethylamine-N-Oxide in a Young Population|published=2018 May 15|authors=Lemos BS, Medina-Vera I, Malysheva OV, Caudill MA, Fernandez ML|journal=J Am Coll Nutr|][reference|url=https://pubmed.ncbi.nlm.nih.gov/32464420|title=Whole egg consumption increases plasma choline and betaine without affecting TMAO levels or gut microbiome in overweight postmenopausal women.|published=2020 Jun|authors=Zhu C, Sawrey-Kubicek L, Bardagjy AS, Houts H, Tang X, Sacchi R, Randolph JM, Steinberg FM, Zivkovic AM|journal=Nutr Res|][reference|url=https://pubmed.ncbi.nlm.nih.gov/29313753|title=Compared to an Oatmeal Breakfast, Two Eggs/Day Increased Plasma Carotenoids and Choline without Increasing Trimethyl Amine N-Oxide Concentrations|published=2018 Feb|authors=Missimer A, Fernandez ML, DiMarco DM, Norris GH, Blesso CN, Murillo AG, Vergara-Jimenez M, Lemos BS, Medina-Vera I, Malysheva OV, Caudill MA|journal=J Am Coll Nutr|][reference|url=https://pubmed.ncbi.nlm.nih.gov/28091798|title=Intake of up to 3 Eggs/Day Increases HDL Cholesterol and Plasma Choline While Plasma Trimethylamine-N-oxide is Unchanged in a Healthy Population|published=2017 Mar|authors=DiMarco DM, Missimer A, Murillo AG, Lemos BS, Malysheva OV, Caudill MA, Blesso CN, Fernandez ML|journal=Lipids|][reference|url=https://pubmed.ncbi.nlm.nih.gov/35334836|title=Comparison between Egg Intake versus Choline Supplementation on Gut Microbiota and Plasma Carotenoids in Subjects with Metabolic Syndrome.|published=2022 Mar 11|authors=Thomas MS, DiBella M, Blesso CN, Malysheva O, Caudill M, Sholola M, Cooperstone JL, Fernandez ML|journal=Nutrients|] Some studies have associated higher choline intakes with increased atrial fibrillation risk[reference|url=https://pubmed.ncbi.nlm.nih.gov/29650710|title=Plasma Concentrations and Dietary Intakes of Choline and Betaine in Association With Atrial Fibrillation Risk: Results From 3 Prospective Cohorts With Different Health Profiles.|published=2018 Apr 12|authors=Zuo H, Svingen GFT, Tell GS, Ueland PM, Vollset SE, Pedersen ER, Ulvik A, Meyer K, Nordrehaug JE, Nilsen DWT, Bønaa KH, Nygård O|journal=J Am Heart Assoc|] and type 2 diabetes.[reference|url=https://pubmed.ncbi.nlm.nih.gov/37816243|title=Dietary Intakes of Choline and Betaine and Incidence of Type 2 Diabetes: Tehran Lipid and Glucose Study.|published=2023 Dec|authors=Hosseini-Esfahani F, Koochakpoor G, Golzarand M, Mirmiran P, Azizi F|journal=Metab Syndr Relat Disord|]

Dietary choline is a precursor for the neurotransmitter acetylcholine (ACh), which is crucial for normal cognitive and motor function. Choline is irreversibly oxidized into betaine in the liver and kidneys. Betaine is a methyl group donor that participates in the important process of remethylating homocysteine to methionine. Choline is also a precursor for the synthesis of phosphatidylcholine, the most abundant form of phospholipid in the body.[reference|url=https://pubmed.ncbi.nlm.nih.gov/30332744|title=Dietary Choline Intake: Current State of Knowledge Across the Life Cycle.|published=2018 Oct 16|authors=Wiedeman AM, Barr SI, Green TJ, Xu Z, Innis SM, Kitts DD|journal=Nutrients|]

Choline is important for neural tube closure, stem cell proliferation, and apoptosis (programmed cell death) in the fetal brain during early pregnancy. The choline metabolite phosphatidylcholine is also required for packaging and exporting very-low-density lipoproteins from the liver and the secretion of bile acid salts; the disruption of this process can contribute to the accumulation of triglycerides in the liver.[reference|url=https://pubmed.ncbi.nlm.nih.gov/4340541|title=Effects of choline-deficient diets on the rat hepatocyte. Electron microscopic observations.|published=1970 Dec|authors=Bruni C, Hegsted DM|journal=Am J Pathol|][reference|url=https://pubmed.ncbi.nlm.nih.gov/5725875|title=Choline-deficiency fatty liver: impaired release of hepatic triglycerides.|published=1968 Jul|authors=Lombardi B, Pani P, Schlunk FF|journal=J Lipid Res|][reference|url=https://pubmed.ncbi.nlm.nih.gov/9498371|title=Hepatic and renal betaine-homocysteine methyltransferase activity in pigs as affected by dietary intakes of sulfur amino acids, choline, and betaine.|published=1998 Feb|authors=Emmert JL, Webel DM, Biehl RR, Griffiths MA, Garrow LS, Garrow TA, Baker DH|journal=J Anim Sci|][reference|url=https://pubmed.ncbi.nlm.nih.gov/3182819|title=Kinetic mechanism of phosphatidylethanolamine N-methyltransferase.|published=1988 Nov 15|authors=Ridgway ND, Vance DE|journal=J Biol Chem|][reference|url=https://pubmed.ncbi.nlm.nih.gov/10417327|title=Apolipoprotein B mRNA and lipoprotein secretion are increased in McArdle RH-7777 cells by expression of betaine-homocysteine S-methyltransferase.|published=1999 Aug 1|authors=Sowden MP, Collins HL, Smith HC, Garrow TA, Sparks JD, Sparks CE|journal=Biochem J|]