Choline has only recently been recognized as an essential nutrient. Choline is part of the neurotransmitter acetylcholine, which plays a major role in the brain; for this reason, many studies have been designed to look at choline's role in brain function.
Choline functions as a part of a major biochemical process in the body called methylation; choline acts as a methyl donor. Until recently, it was thought that the body could use other substances to substitute for choline, such as folate , vitamins B 6 and B 12 , and the amino acid methionine . But recent evidence has finally shown that, for some people, adequate choline supplies cannot be maintained by other nutrients and must be obtained independently through diet or supplements. 1-3
Choline is widespread in the foods we eat. The average diet provides about 500 mg to 1,000 mg of choline per day. 2,4 Lecithin, a fatty constituent in foods, is a major source of choline; it is comprised mostly of a type of choline called phosphatidylcholine (PC). Lecithin and PC have been studied separately as treatments for a variety of illnesses; for more information on these supplements, see the full article on Lecithin .
According to US and Canadian guidelines, the recommended daily intake of choline is as follows:
Most studies of choline as a treatment for diseases have used between 1-30 g of choline or choline-containing supplements per day. This wide range is due to the existence of several different types of choline supplements, all with varying amounts of the active ingredient.
Slight evidence hints that lecithin or pure choline may be helpful for people with bipolar disorder . 7,29 Lecithin has failed to prove effective for tardive dyskinesia . 8,9 Lecithin has also failed to prove effective for improving cholesterol profile levels. 2,10
Some evidence suggests that individuals with HIV who are low in choline may experience more rapid disease progression. 11 However, there is no direct evidence that choline supplements offer any benefit for people with HIV.
Numerous studies have found that diets very low in choline lead to impaired liver function. 1,2,12-15 But these diets are contrived: One would have to work very hard to get so little choline in the diet! To what degree additional choline may benefit people with pre-existing liver damage is an area of ongoing research. In a double-blind study , use of phosphatidylcholine enhanced the effect of interferon in people with chronic hepatitis C, but not those with chronic hepatitis B. 16Open studies have yielded mixed results. 17,18
Finally, there are theoretical reasons to believe that choline might have cancer-preventive properties. The notion stems from its function as a methyl donor. Methyl units are essential for RNA and DNA replication—a process ongoing in every cell of the body. The theory goes like this: Diets lacking sufficient methyl donors (such as choline) may cause an error in RNA or DNA synthesis, leading to a mutated gene and, hypothetically, to cancer initiation. 1,19 Indeed, in rats fed diets very low in choline and other methyl donors, cancer rates increased. 20,21 However, again it is a long step from the effects of an artificially low-choline diet to taking choline supplements.
Choline as phosphatidylcholine may reduce homocysteine levels. 30 This, in turn, might reduce heart disease risk, although the proposed homocysteine-heart disease connection remains far from proven. (See the High Homocysteine article for more information.)
In a 6-month, double-blind, placebo-controlled trial , 261 people with mild to moderate Alzheimer’s disease were given either placebo or choline alfoscerate (a special form of choline) at a dose of 400 mg 3 times daily. 5 The results indicated that people receiving the supplement improved slightly over the course of the trial, while those given placebo worsened.
Weak evidence from highly preliminary studies hint that CDP-choline may improve mental function in Alzheimer’s disease. 22-25 Double-blind trials using lecithin as a source of choline failed to find benefit. 26-28
Four double-blind, placebo-controlled studies enrolling a total of 1,372 people have evaluated the potential effectiveness of CDP choline in the treatment of strokes . 6 Overall, the evidence suggests that use of CDP-choline in the immediate period following a stroke slightly improves the chances of full recovery.
The tolerable upper intake of choline has been set at 3.5 g daily for adults. Tolerable upper intake is defined as: the highest daily intake over a prolonged time known to pose no risks to most members of a healthy population.
In higher dosages, minor but annoying side effects may occur, such as abdominal discomfort, diarrhea, and nausea. Maximum safe dosages for young children, pregnant or nursing women, or those with severe liver or kidney disease have not been determined.
5. De Jesus Moreno Moreno M. Cognitive improvement in mild to moderate Alzheimer's dementia after treatment with the acetylcholine precursor choline alfoscerate: A multicenter, double-blind, randomized, placebo-controlled trial. Clin Ther . 2003;25:178-193.
10. Oosthuizen W, Vorster HH, Vermaak WJ, et al. Lecithin has no effect on serum lipoprotein, plasma fibrinogen and macro molecular protein complex levels in hyperlipidaemic men in a double-blind controlled study. Eur J Clin Nutr . 1998;52:419-424.
13. Buchman AL, Dubin M, Jenden D, et al. Lecithin increases plasma free choline and decreases hepatic steatosis in long-term total parenteral nutrition patients. Gastroenterology. 1992;102:1363-1370.
16. Niederau C, Strohmeyer G, Heintges T, et al. Polyunsaturated phosphatidyl-choline and interferon alpha for treatment of chronic hepatitis B and C: a multi-center, randomized, double-blind, placebo-controlled trial. Leich Study Group. Hepatogastroenterology. 1998;45:797-804.
22. Alvarez XA, Mouzo R, Pichel V, et al. Double-blind placebo-controlled study with citicoline in APOE genotyped Alzheimer's disease patients. Effects on cognitive performance, brain bioelectrical activity and cerebral perfusion. Methods Find Exp Clin Pharmacol. 1999;21:633-644.
23. Franco-Maside A, Caamano J, Gomez MJ, et al. Brain mapping activity and mental performance after chronic treatment with CDP-choline in Alzheimer's disease. Methods Find Exp Clin Pharmacol. 1994;16:597-607.
30. Olthof MR, Brink EJ, Katan MB, et al. Choline supplemented as phosphatidylcholine decreases fasting and postmethionine-loading plasma homocysteine concentrations in healthy men. Am J Clin Nutr. 2005;82:111-7.
Last reviewed August 2013 by EBSCO CAM Review Board
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