Choline's metabolism is closely interrelated to that of methionine, and methyl-folate, yet choline is at times treated by some nutritional specialists as a stepchild in nutrition.

Choline is one of the "lipotropic" B vitamins—that is, it helps the utilization of fats in the body and thereby supports weight loss. This vitamin is widely available in food but is sensitive to water and may be destroyed by cooking, food processing, improper food storage, and the intake of various drugs, including alcohol, estrogen, and sulfa antibiotics.

Choline is easily absorbed from the intestines and is one of the only vitamins that crosses the blood-brain barrier into the spinal fluid to be involved directly in brain chemical metabolism. Choline is referred to as the "memory" vitamin, as it is an important part of the neurotransmitter acetylcholine.

Choline assists in controlling your weight as well as cholesterol levels, keeping cell membranes healthy and in preventing gallstones. It is also most useful in the maintenance of the nervous system, assisting memory and learning, and may help to fight infections, including hepatitis and AIDS. Choline is critical for normal membrane structure and function.

Choline is the major precursor of betaine, and it is used by the kidneys to maintain water balance and by the liver as a source of methyl-groups for methionine formation. It is also used to produce the important neurotransmitter acetylcholine. It assists in nerve impulse transmission, gallbladder regulation, liver functions and lecithin production.

A deficiency of choline does not happen easily but if it is deficient it may lead to liver disease, hardening of the arteries, heart problems, raised cholesterol levels, high blood pressure, as well as hemorrhaging kidneys. Choline deficiency may also manifest itself in the inability to digest fats, stunted growth and fatty buildup in the liver. Memory and brain function could also be impaired.

The maximum level of choline has been set for safety at 3.5 g/day. Taking too much choline could result in your body smelling fishy, may cause nausea, depression, and could trigger existing epilepsy. Hypotension, sweating, salivation and diarrhea have also been reported.

Choline is found in egg yolks, beef, wheat germ, oats, nuts.

Choline, together with fat, inositol and essential unsaturated fatty acids makes up lecithin. It needs a co-enzyme containing vitamin B6, and magnesium to be produced. If lecithin is in short supply it may allow your blood cholesterol levels to become elevated.