Choline

Description

The classification of choline as a vitamin is debated because deficiency symptoms in humans have not been reported. Apparently, the biosynthesis of choline meets the needs of the body and, unlike other vitamins, it serves more as a structural role in fat and nerve tissue than as a cofactor in enzymatic catalysis.

Choline is the constituent of many phospholipids, mainly lecithin. As acetylcholine, it is used in the transmission of nerve impulses between nerve junctions.

Method of Action

Choline is biosynthesized in the body from serine and methionine. Vitamin B-12 and folacin are both needed as cofactors in the enzymes that catalyze the biochemical steps.

Choline has many functions in the body. It is a component of many phospholipids; it is used in the transmission of nerve impulses and as a methyl group donor in other biochemical reactions.

Choline prevents the formation of fatty liver by promoting the production of lecithin, which is a derivative of choline.

Choline, when joined with a acetate group, forms acetylcholine; the compound responsible for the transmission of nerve impulses between individual nerve cells.

Choline is used as a methyl group donor in other biochemical steps in the body as well. The methyl group on choline can be transferred to another compound for the formation of hormones, such as epinephrine, or the methylation of other substances for excretion.

Properties & Uses

Choline has been used in the treatment of common liver disorders in humans, such as fatty liver or cirrhosis from alcoholism with inconsistent results.

It is doubtful that any promising results were due to anything more than an improved diet since choline deficiency has not been known to cause liver disorders other than in animals.

Consequence of Deficiency

Choline deficiency has never been seen in humans. In other mammals the symptoms of deficiency are poor growth, kidney damage, and fatty livers.

Toxicity Factors

No toxic effects of choline have been reported. However, ingestion of 20 grams per day for several weeks (as may occur in the treatment of fatty liver, alcoholism, or kwashiorkor) has produced symptoms of dizziness, diarrhea, and nausea.

Recommended Dietary Allowance

No RDA has been established for choline by the national Academy of Science Food and Nutrition Board since choline is produced by the body and hence not considered an essential dietary factor for good health.

The average daily intake from diet (400 to 900 milligrams per day) is adequate but should not be considered a dietary requirement.

Food Sources

High
Beef liver
Egg, especially egg yolk
Lamb liver
Pork liver

Medium

Alfalfa leaf meal	Potatoes
Barley	Rice
Buttermilk (dried)	Rice bran
Cabbage	Soybeans
Corn	Turnips
Navy beans	Wheat bran
Oat flakes	Whole wheat

Abstracts

References

Ensminger, A.H., M.E. Ensminger, J.E. Konlande, & J.R.K. Robson. 1983. Foods & Nutrition Encyclopedia, vol 1. Pegus press, Clovis, CA.

Goodhart, Robert S. and Maurice E. Shills. Modern Nutrition In Health And Disease. 6th edition. Philadelphia: Lea and Febiger, 1973.

Jacob-RA et al: In vivo methylation capacity is not impaired in healthy men during short-term dietary folate and methyl group restriction. J-Nutr. 1995 Jun; 125(6): 1495-502.

Osol, Arthur. 1980. Remington's Pharmaceutical Sciences. Mack Publishing Company, Pennsylvania. 1928.

Recommended Dietary Allowances. 1989. National Academy of Science, National Academy Press, Washington, D.C.

Tver, David F. 1981. The nutrition and health encyclopedia. Van Nostrand Reinhold Company Inc., N.Y.

Walji, Hasnain. 1992. The Vitamin Guide-Essential Nutrients for Healthy Living, Element Books, Dorset .U.K.

Walji, Hasnain. 1994. Vitamins, Minerals and Dietary Supplements - A definitive Guide to Healthy Eating . Hodder Headline Plc. London.