choline

What can high-choline foods do for you?

  • Keep your cell membranes, the gates through which nutrients enter and wastes leave your cells, functioning properly
  • Allow your nerves to communicate with your muscles
  • Prevent the build-up of homocysteine in your blood. Homocysteine is a harmful compound that is associated with cardiovascular disease and osteoporosis.

What events can indicate a need for more high-choline foods?

  • Fatigue
  • Insomnia
  • Poor ability of the kidneys to concentrate urine
  • Accumulation of fats in the blood
  • Nerve-muscle problems

Food sources of choline include soybeans, egg yolk, butter, peanuts, potatoes, cauliflower, lentils, oats, sesame seeds and flax seeds. (Insufficient research is currently available to classify food sources of choline according to our excellent, very good and good rating system.)

 

Description

What is choline?

Choline, the newest official member of the B vitamin family, had its Adequate Intake levels (AIs) established for the first time by the National Academy of Sciences in 1998. Even though it has only recently been adopted into the official family of vitamins, choline has been the subject of nutritional investigations for almost 150 years.

Key research discoveries about choline came in the late 1930s, when scientists discovered that tissue from the pancreas contained a substance that could help prevent fatty build-up in the liver. This substance was named choline after the Greek word chole, which means bile. Since the 1930s, research has shown that choline is found not only in the pancreas and liver, but is also, in fact, a component of every human cell.

Research has also shown that the naming of choline after the Greek word for bile was highly appropriate. Bile, which is made in our liver, has the primary job of making fat compatible with water, so that fat-based substances can get transported around the body in the water-based world of our blood. Choline has very similar fat-modifying effects in the membranes of our cells. The fat-modifying properties of choline allow our cell membranes to operate with greater flexibility in handling both water- and fat-soluble molecules. Without choline, many fat-based nutrients and waste products could not pass in and out of our cells.

In addition to its uniqueness as a fat-modifying substance, choline is chemically unique as a trimethylated molecule. The term methylated means that a substance has at least one special chemical group - called a methyl group - attached to it. Choline is trimethylated, meaning three methyl groups are attached. Many important chemical events in the body are made possible by the transfer of methyl groups from place to place. Genes in the body can be turned on and turned off in this way, and cells often use this same process to send messages back and forth. In the area of mental health, where messages sent from nerve to nerve are especially critical, choline has turned out to be a substance of great interest.

How it Functions

What is the function of choline?

Maintenance of Cell Membrane Integrity

Choline is a key component of many fat-containing structures in cell membranes. Since cell membranes are almost entirely composed of fats, the membranes' flexibility and integrity depend on adequate supplies of choline. Membrane structures that require choline include phosphatidylcholine and sphingomyelin. In the brain, these fat-like molecules account for an unusually high percentage of total solids, so choline is particularly important for brain health, and its potential for use in brain disorders is great.

Support of Methyl Group Metabolism

Choline’s chemical uniqueness as a trimethylated molecule makes it highly important in methyl group metabolism. The term methyl group refers to a chemical structure with only one carbon atom and three hydrogen atoms, and the term methylated means that a substance has at least one methyl group. Choline is endowed with three methyl groups. Many important chemical events in the body are made possible by the transfer of methyl groups from one place to another. For example, genes in the body can be switched on or turned off in this way, and cells can use methylation to send messages back and forth.

Support of Nervous System Activity

Choline is a key component of acetylcholine, a messenger molecule found in the nervous system. Acetylcholine, also called a neurotrasmitter since it carries messages from and to nerves, is the body's primary chemical means of sending messages between nerves and muscles. Because of its role in nerve-muscle function, choline (supplemented in the form of lecithin, or phosphatidylcholine), has been used experimentally to help improve neuromuscular function in Alzheimer’s disease.

Deficiency Symptoms

What are deficiency symptoms of choline?

Of special importance in the relationship between choline and health is the impact of choline deficiency on the risk of coronary heart disease (CHD) and other cardiovascular problems. Risk of CHD and other heart/circulatory problems is associated with high blood levels of a molecule called homocysteine. Many factors can contribute to high levels of homocysteine in the blood, but one factor clearly involves choline deficiency since choline allows homocysteine to be converted into other substances, thus preventing any build-up.

Mild deficiency of choline has also been linked to fatigue, insomnia, poor ability of the kidneys to concentrate urine, problems with memory, and nerve-muscle imbalances. Choline deficiency can also cause deficiency of another B vitamin critically important for health, folic acid.

Extreme dietary deficiency of choline can result in liver dysfunction, cardiovascular disease, impaired growth, abnormalities in bone formation, lack of red blood cell formation, infertility, respiratory distress in newborns, failure to thrive in newborns, kidney failure, anemia, and high blood pressure. In the case of high blood pressure and respiratory distress, the impact of choline deficiency may be to rob the body of its nervous system messenging molecule, acetylcholine, which cannot be made without choline.

In the case of kidney failure and red blood cell formation, the disruption may be related to inadequacy of phosphatidylcholine, a cell membrane component that cannot be made without choline. Finally, many of these problematic events may be related to a breakdown in fat transport and metabolism that makes fat unavailable as an energy source.

The consequences of choline deficiency are particularly visible in the liver since a lack of choline prevents the liver from packaging and transporting fat in a natural pattern. The primary symptom of this change in fat-packaging is a decrease in the blood level of VLDL (which stands for very low-density lipoprotein, a complex fat-containing molecule that the liver uses to transport fat). As part of this same unnatural pattern, levels of certain fats in the blood, called triglycerides, can also become greatly increased as a result of choline deficiency.

Toxicity Symptoms

What are toxicity symptoms for choline?

High doses of choline (10-15 grams) have been linked in the research literature with unusual body odor, vomiting, increased salivation, and sweating. The symptom of unusual body odor appears to be associated with increased presence of a breakdown product of choline called trimethylamine. Doses of choline in the 5-10 gram/day range have also been associated with reductions in blood pressure and in some subjects, feelings of faintness or dizziness. The National Academy of Sciences has established a Tolerable Upper Intake Level (UL) of 3.5 grams/day for choline, based primarily upon risk of decreased blood pressure.

Impact of Cooking, Storage and Processing

How do cooking, storage & processing affect choline?

Although consistent information is not available on the effects of cooking, storage, and processing on the choline content of food, choline’s participation in cell membranes and in the fatty portion of food renders it susceptible to alteration by oxygen and heat. While maximizing choline content would not be a good reason to choose raw egg yolk over cooked egg yolk (too many safety risks are involved with raw egg yolk), overcooking of foods high in choline would be a practice worth avoiding to help preserve choline content.

Factors that Affect Function

What factors might contribute to a deficiency of choline?

In addition to poor dietary intake of choline itself, poor intake of other nutrients can result in choline deficiency. These nutrients include vitamins B-3, folic acid, and the amino acid methionine. The reason that these other nutrients can cause choline deficiency inolves the unusual chemical structure of choline as a "trimethylated" molecule.

"Trimethylated" means that choline has three chemical components called methyl groups. In order for choline to obtain all three methyl groups, vitamins B3, folic acid, and the amino acid methionine are required.

Liver problems, including liver cirrhosis, are common contributing factors to choline deficiency. Finally, a variety of hospital procedures, including TPN feeding (total parenteral nutrition directly into the bloodstream), by-pass surgery, and kidney transplant are also direct triggers of choline deficiency.

Drug-Nutrient Interactions

What medications affect choline?

Methotrexate – a drug used primarily in the treatment of cancer, but also in the treatment of rheumatoid arthritis and psoriasis - and anticonvulsant drugs have both been shown to increase risk of choline deficiency.

Nutrient Interactions

How do other nutrients interact with choline?

As part of a complicated chemical cycle called the SAM cycle (s-adenosyl-methionine cycle), choline adequacy is closely related to the adequacy of many other nutrients. These nutrients include vitamins B-6, B-12, and folate; the amino acids serine and glycine; and the molecules betaine, sarcosine, and ethanolamine.

Throughout the SAM cycle, all of these molecules are actively exchanging chemical components - and especially chemical structures called methyl groups - in order to keep the body supplied with adequate amounts of SAM. In the context of the SAM cycle, one of choline's jobs is to keep methyl groups cycling around for eventual donation to SAM.

The movement of methyl groups around the SAM cycle is particularly dependent on folic acid, which is particularly good at accepting methyl groups from other molecules. For this reason, folate deficiency is especially likely to disrupt SAM cycle balance, and in the process, choline status as well.

Health Conditions

What health conditions require special emphasis on choline?

Because of its importance in fat metabolism, choline status is important to evaluate in virtually all health problems involving the liver, including alcoholism and cirrhosis. Epilepsy, Parkinson’s disease, Alzheimer’s disease, memory deficit problems, attention deficit and hyperactivity disorders, neuromuscular disorders, cardiovascular diseases (especially coronary heart disease), brain disorders, autism, failure to thrive in newborns, respiratory distress in newborns, hypertriglyceridemia, hyperhomocysteineimia, anemia, infertility, high blood pressure, and candidiasis all justify a close look at choline adequacy.

Along with the other SAM cycle nutrients, choline status may also be important to consider in reducing the toxic effects of heavy metals in the body, including lead. Although the exact role for choline in helping protect against heavy metal toxicity is not clear, the process is definitely not a simple one merely involving the methylation of heavy metals. The attaching of methyl groups to heavy metals often increases, rather than lowers, their toxicity.

Form in Dietary Supplements

What forms of choline are found in dietary supplements?

Lecithin (phosphatidylcholine), usually extracted in the commercial marketplace from soybean, is the most common form of supplemental choline. Choline itself is also widely available. Although choline in many supplements is derived from soy, soy-free supplements are also available. Many of these contain choline in the form of choline bitartrate.

The lecithin form of choline may be better able to increase choline levels in the body, perhaps due to the lesser breakdown of lecithin by bacteria in the intestinal tract. This form of the supplement is usually obtained from soybeans.

Food Sources

Introduction to Nutrient Rating System Chart

The following chart shows the foods which are either excellent, very good or good sources of this nutrient. Next to each food name you will find the following information: the serving size of the food; the number of calories in one serving; DV% (percent daily value) of the nutrient contained in one serving (similar to other information presented in the website, this DV is calculated for 25-50 year old healthy woman); the nutrient density rating; and the food's World's Healthiest Foods Rating. Underneath the chart is a table that summarizes how the ratings were devised. For more detailed information on our Nutrient Rating System, please click here.

 

Public Health Recommendations

What are current public health recommendations for choline?

In 1998, the National Academy of Sciences established Adequate Intake (AI) levels for choline as follows:

  • 0-6 months: 125 milligrams
  • 6-12 months: 150 milligrams
  • 1-3 years: 200 milligrams
  • 4-8 years: 250 milligrams
  • males 9-13 years: 375 milligrams
  • males 14 years and older: 550 milligrams
  • females 9-13 years: 375 milligrams
  • females 14-18 years: 400 milligrams
  • females 19 years and older: 425 milligrams
  • Pregnant females of any age: 450 milligrams
  • Lactating females of any age: 550 milligrams

Prevention of liver damage was the main criterion used in establishment of these recommended levels.

References

  • Arnesen E, Refsum H, Bonaa KH, et al. Serum total homocysteine and coronary heart disease. Intnl J Epidem 1995;24:704-709.
  • Etienne P, Gauthier S, Dastoor D, et al. Alzheimer's disease: clinical effects of lecithin treatment. Chapter 5. In: Barbeau A, Growdon JH, and Wurtman RJ (Eds). Nutrition and the brain. Raven Press, New York, 1979;389-396.
  • Groff JL, Gropper SS, Hunt SM. Advanced Nutrition and Human Metabolism. West Publishing Company, New York, 1995.
  • Hirsch MJ, Growdon JH, Wurtman RJ. Relations between dietary choline or lecithin intake, serum choline levels, and various metabolic indices. Metabol 1978;27:953-960.
  • James SJ, Yin L. Diet-induced DNA damage and altered nucleotide metabolism in lymphocytes from methyl-donor-deficient rats. Carcinogen 1989;10(7):1209-1214.
  • National Academy of Sciences. Dietary Reference Intakes: Thiamin, Riboflavin, Niacin, Vitamin B-6, Vitamin B-12, Pantothenic Acid, Biotin, and Choline. Institute of Medicine, Food and Nutrition Board, National Academy of Sciences. Washington, DC, National Academy Press, 1998;390-422.
  • Paredes SR, Kozicki PA, Battle AM. S-adenosyl-methionine a counter to lead intoxication. Comp Biochem Physiol 1985;[B] 82(4):751-757.
  • Schwahn BC, Chen Z, Laryea MD et al. Homocysteine-betaine interactions in a murine model of 5,10- methylenetetrahydrofolate reductase deficiency. FASEB J 2003 Mar;17(3):512-4.
  • Ueland PM, Refsum H. Plasma homocysteine, a risk factor for vascular disease: plasma levels in health, disease, and drug therapy. J Lab Clin Med 1989;473-501.
  • Zeisel SH. Choline and phosphatidylcholine. In Shils M et al. (Eds). Nutrition in Health and Disease. Ninth Edition. Williams & Wilkins, Baltimore, 1999;513-523.
  • Zeisel SH. Choline and lecithin. In: Sadler MJ. (Ed.-in-Chief). Encyclopedia of human nutrition. Academic Press, San Diego, 1998.
  • Zeisel SH, Blusztajn. Choline and human nutrition. Ann Rev Nutr 1994;14:269-271.

This page was updated on: 2003-12-13 00:28:52
© 2002 The George Mateljan Foundation

Foods Ranked as quality sources of:
choline
Data not available for food sources of choline