What Is Choline?

Choline is an essential nutrient found naturally in foods and produced in small amounts by the liver. Both plants and animals need choline to maintain cell structure.

Choline has many functions in the human body, including:

• Forming acetylcholine, one of seven major neurotransmitters responsible for many nervous system functions
• Supporting the integrity of cell membranes
• Removing fat and cholesterol from the liver
• Making compounds needed for cell signaling

Your body does not make all the choline necessary, so you must consume the rest from your diet. Choline can also be found as a nutritional supplement. This article reviews choline, how to get it in your diet, and who is at risk for not getting enough of this nutrient.

Uses of Choline

Choline has been suggested to play a role in cardiovascular health, prevention of liver disease, and improvement in brain function. Many of these roles have evidence that indicates a correlation but not necessarily causation. This means we cannot definitively say if choline is effective for these uses. For example, higher levels of choline intake in the diet are associated with improved cognitive function. However, clinical trials have not found that supplementing with choline directly improved cognitive function.

There is not enough evidence to support many uses of choline supplementation. An exception would be people requiring long-term parenteral nutrition (PN), or tube or intravenous (IV) feeding. PN does not routinely contain choline. Nonalcoholic fatty liver disease (NAFLD) has been reported in people who need PN as their sole source of nutrition.

Below are some of the areas where choline supplementation has been studied:

• Nonalcoholic fatty liver disease
• Heart disease
• Cognitive function

Nonalcoholic Fatty Liver Disease

Most choline is converted to phosphatidylcholine, a major phospholipid that helps build fat-carrying proteins. Phosphatidylcholine helps carry fat away from the liver. Without choline, fat can accumulate in the liver, increasing the risk of developing nonalcoholic fatty liver disease.

Although choline deficiency can cause NAFLD, there is limited research on whether supplementation can treat the condition once it has developed. One clinical trial evaluating a nutraceutical mixture containing choline found that it was of no benefit in people who already have NAFLD.

Heart Health

Choline plays a role in reducing homocysteine levels. High homocysteine levels are a risk factor for heart disease. This has led researchers to consider whether choline might help reduce the risk of heart disease.

However, the results have been mixed:

• A study published in the European Journal of Nutrition found that higher choline intake was associated with a reduced risk of stroke. The study included data from 3,924 African Americans who took food frequency questionnaires and had follow-up tests for heart disease measures.
• In a study published in Atherosclerosis, no association was found between choline intake and heart-related risks. The research included an analysis of 72,348 women in the Nurses' Health Study and 44,504 men in the Health Professionals Follow-Up Study.
• Another study suggested higher intakes of choline in the diet were associated with an increased risk of death from heart disease. This may be related to converting choline to make trimethylamine N-oxide (TMAO). High levels of TMAO have been associated with a greater risk of heart disease. However, this finding was more pronounced in people with diabetes than those without.

Further research is needed to determine choline's role in heart health.

Cognitive Function

Choline is needed to make acetylcholine, which has a role in memory and thinking. Higher intakes of choline have been associated with higher levels of cognitive function, but that does not necessarily mean that choline supplementation can directly improve cognition.

For example, a systematic review published in 2015 found that choline supplementation did not result in improved cognition in healthy people. Additionally, a Cochrane review concluded that lecithin (a source of choline) supplementation resulted in no clear benefits. There is also interest in choline's possible role in Alzheimer's disease, but further research is needed.

Choline Deficiency

Most people don't consume enough choline in their diet. However, deficiency is rare because your body can make choline.

When it does occur, choline deficiency can eventually lead to muscle and liver damage.

What Causes a Choline Deficiency?

Choline deficiency occurs when intake in the diet is not adequate.

How Do I Know if I Have a Choline Deficiency?

Choline status is not routinely measured in healthy people.

If measured, normal plasma choline levels range from 7 to 20 micromoles/liter (mcmol/L).

Groups at Risk of Choline Deficiency

The following groups are at higher risk of developing a choline deficiency:

• Pregnant people
• People with certain genetic alterations of genes involved in metabolizing choline, folate, and methionine
• People who require parenteral nutrition, since choline is not routinely added to parenteral solutions

Pregnant women are at risk of choline deficiency because their requirements are higher and they don't get enough choline in their diet. Historically, many prenatal vitamin formulations did not contain choline. Check the supplement facts label for choline content in prenatal vitamins.

Postmenopausal women are also at greater risk.

What Are the Side Effects of Choline?

Side effects of choline supplementation include:

• Sweating
• Fishy body odor
• Nausea or vomiting
• Diarrhea

In severe cases, hypotension (low blood pressure) could occur. Taking an excessive dose of choline can cause side effects involving the gastrointestinal (GI) tract. However, these often resolve after discontinuing the supplement.

Precautions

Though supplementing with choline is likely safe for most people in doses less than 3.5 g daily, adequate intake (AI) is actually much lower.

For pregnant women, choline supplementation appears to be safe in amounts up to 3 g daily if under 18 or 3.5 g daily if over 19 years of age.

Choline supplementation is likely safe in children in appropriate amounts.

Dosage: How Much Choline Should I Take?

Always speak with a healthcare provider before taking a supplement to ensure that the supplement and dosage are appropriate for your individual needs.

Not enough evidence is available to provide a recommended dietary allowance (RDA) for choline, but an adequate intake has been established.

Choline supplementation is likely safe for most people in doses less than 3.5 g daily.

What Happens if I Take Too Much Choline?

Supplementing excessive amounts of choline is more likely to result in side effects. Adults should not take more than 3.5 g daily.

High intakes of choline can result in:

• Sweating
• Body odor
• Diarrhea
• Vomiting
• Hypotension
• Liver toxicity

If you experience side effects, discontinue supplementation and discuss with your healthcare provider.

Interactions

No clinically relevant interactions between choline and medications are known.

How to Store Choline

Follow the directions on the supplement label for storage. Always keep out of reach of children to prevent accidental consumption.

Sources of Choline and What to Look For

According to the Dietary Guidelines for Americans, most choline should be consumed through diet. Foods that contain choline include: 

• Animal-based foods, such as meat, eggs, dairy, and fish
• Nonanimal sources including nuts, seeds, whole grains, and legumes
• Apples, tangerines, kiwi, and cruciferous vegetables such as broccoli and cabbage

Choline Supplements

Choline supplements are widely available. They can be found as an individual nutrient supplement, combined with B vitamins, or combined into a multivitamin or multimineral product.

Choline supplements typically come in the form of choline bitartrate, phosphatidylcholine, and lecithin. There is no research available to suggest that one form is better than another.

Typical dosages in supplements range from 10 mg to 250 mg.

Summary

Choline is an essential nutrient. It is made in the body but not in adequate amounts, so more is needed from your diet. It is best to get choline from the foods you eat.

Foods rich in choline include:

• Meats
• Eggs
• Chicken
• Soybeans
• Kidney beans
• Quinoa

Some people may need to supplement with choline if they can't get enough through their diet. But many of the claims about supplementing choline are not supported by research.

If you have concerns about your choline level and how it may be affecting your health, talk with your healthcare provider. If you are pregnant, review your risk of deficiency with your prenatal care provider. Consult with a medical professional before taking any supplements.