Herbs & Supplements:
Choline

Principal Proposed Uses
  • · There are no well-documented uses for choline
Other Proposed Uses
  • Alzheimer's Disease, Other Neurological Conditions, High Cholesterol, HIV Support, Liver Disease, Cancer Prevention

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 B₆ and B₁₂, and the amino acid methionine. But recent evidence has finally shown that, for many people, adequate choline supplies cannot be maintained by other nutrients, and must be obtained independently through diet or supplements.^1,2,3

Requirements/Sources

Choline is widespread in the foods we eat. The average diet provides about 500 to 1,000 mg of choline per day.^4,5 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 U.S. and Canadian guidelines, the recommended daily intake of choline is as follows:

• Infants 0–6 months, 125 mg
  7–12 months, 150 mg
• Children 1–3 years, 200 mg
  4–8 years, 250 mg
  9–13 years, 375 mg
• Males 14 years and older, 550 mg
• Females 14–18 years, 400 mg
  19 years and older, 425 mg
• Pregnant women, 450 mg
• Nursing women, 550 mg
• Tolerable upper intake level (UL) for adults, 3.5 g*

*The "tolerable upper intake level" can be thought of as the highest daily intake over a prolonged time known to pose no risks to most members of a healthy population.

Therapeutic Dosages

Most studies of choline as a treatment for diseases have used between 1 and 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.

Therapeutic Uses

Choline, as well as phosphatidylcholine, lecithin, and a special form of choline called citicoline (or CDP-choline) has been studied quite extensively in people with Alzheimer's disease and other conditions involving the brain. As noted above, this research is based on the fact that an important neurotransmitter, acetylcholine, is made from choline. We know that eating a lot of choline raises blood levels of choline, but we don't know the degree to which this enhances acetylcholine levels and, ultimately, brain function.^6–14 Choline alone does not appear to diminish Alzheimer's symptoms in studies of people diagnosed with the disease.^15–19

In other areas of brain function, two studies showed some benefit from lecithin or pure choline in people with mania or bipolar disorder respectively, but these studies were small and poorly controlled.^51,52 Two other small double-blind placebo-controlled studies examined the effects of lecithin in people with tardive dyskinesia but found no substantial improvement in symptoms.^53,54

One very large (899 participant) double-blind placebo-controlled trial evaluated citicoline for the treatment of strokes, but found no evidence of benefit.⁵⁶  

Choline's reputation as a cholesterol-lowering agent has been extensively studied in trials involving lecithin. Studies showing a positive effect from choline were poorly controlled and lacked a placebo group;^27,28 well-designed studies do not support the claim that choline can reduce cholesterol levels.^29,30 However, preliminary evidence suggests choline—in concert with other methyl donors like folate, methionine, and vitamins B₁₂ and B₆—may help to lower homocysteine levels, which could in turn help prevent heart disease.^31,32

Evidence suggests that individuals with HIV who are low in choline may experience more rapid disease progression.³³

Numerous studies have found that diets very low in choline lead to impaired liver function.^34–39 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 one study, liver function improved in people with hepatitis who were given choline supplements,⁴⁰ but in another study, the same supplement failed to show improvements in individuals with hepatitis.⁴¹ A study of malnourished hospitalized people with cirrhosis showed an improvement in several important measurements of liver function when choline supplements were given.⁴²

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.^43,44 Indeed, in rats fed diets very low in choline and other methyl donors, cancer rates increased.^45,46 However, as noted above in the discussion of liver disease, it is a long step from the effects of an artificially low-choline diet to taking choline supplements.

What Is the Scientific Evidence for Choline?

Alzheimer's Disease

Note: Many of the studies below used PC or lecithin instead of choline. However, because these substances break down to form choline, they are discussed here as well.

Several studies in the early 1980s examined supplemental lecithin in people diagnosed with Alzheimer's disease.^47,48,49 Although the groups studied were small (from 11 to 37 people), these were all double-blind placebo-controlled trials. After 3 to 6 months, no differences in cognitive function could be detected in those getting choline compared to placebo. More promising may be choline in combination with other drugs. A 1989 Canadian study combined lecithin with tetrahydroaminoacridine (THA), a drug that effectively improves symptoms associated with Alzheimer's disease but is toxic to the liver at high doses.⁵⁰ By combining THA with lecithin (3.4 g per day), researchers were able to use lower doses of the drug and achieve comparable improvements in symptoms of Alzheimer's.

Finally, studies in rats and mice found enhanced brain function in animals fed supplemental choline.^55,56 But in studies of healthy adults given lecithin as well as in observational trials evaluating dietary choline intake, little to no benefit was seen.^57,58

Safety Issues

When taken at nutritional doses as recommended above (see Requirements/Sources), choline supplementation is safe. 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.

Last reviewed March 2002 by Medical Review Board

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