Choline

Recent evidence suggests that choline is an essential nutrient in humans. Small quantities are synthesized in the liver with the help of vitamin B12, folic acid and the amino acid, methionine; but the amounts made may not be sufficient to meet daily needs.

What it does in the body

Fat metabolism

Choline is involved in fat metabolism and in the transport of fats from the liver.

Cell membranes

Choline is a component of cell membranes and plays a role in the transmission of signals inside cells. Myelin, the insulating sheath around the nerves, and platelet activating factor contain choline.

Neurotransmitters

Choline accelerates the synthesis and release of the neurotransmitter acetylcholine, which is involved in many nerve and brain functions. Dietary intake of choline seems to affect body levels of acetylcholine.

Absorption

Choline may be absorbed better in the form of lecithin.

Deficiency

Choline deficiency symptoms in humans include fatty liver and liver damage. These symptoms have been demonstrated only recently in humans fed choline- deficient diets.1 This means that choline fulfills one of the criteria for being an essential nutrient. Patients on long-term parenteral nutrition who are not given choline develop fatty infiltration of the liver and other signs of dysfunction. This condition can be improved, and possibly prevented, with choline supplementation.

Choline deficiency in animals also leads to nerve degeneration, senile dementia, high blood cholesterol, and liver cancer - possibly by affecting cell signaling or by generating free radicals and DNA alterations.

Nervous system disorders

Uptake of circulating choline into the brain decreases with age. Choline is important for nerve structure and function; and this change may contribute to the type of dementia in which cholinergic nerves are lost.

Sources

Good sources of choline in the form of lecithin include eggs, organ meats, lean meat, brewer's yeast, legumes such as soybeans, grains, and nuts. It is found in green leafy vegetables as free choline.

Recommended intakes

Adequate intake levels for choline have recently been set in the US. The average daily diet supplies around 1000 mg.

Men 550 mg

Women 425 mg

Pregnancy 450 mg

Lactation 550 mg

The tolerable upper intake limit has been set at 3 g per day.

Choline is actively transported from mother to fetus across the placenta and from mother to infant across the mammary gland. Thus, during pregnancy and lactation, dietary requirements for choline are increased.

Supplements

Alcoholics, diabetics and anyone who has deficiency symptoms may benefit from supplements either of lecithin or of choline. Supplemental choline is often in the form of lecithin. The choline content of supplements varies widely.

Toxic effects

Toxic effects at high doses may include reduced appetite, nausea, gastrointestinal problems and a 'fishy' body odor.

Therapeutic uses of supplements

Dementia

Choline supplements have been used to treat the symptoms of brain diseases such as Alzheimer's disease and Huntington's chorea, in which acetylcholine levels are low due to the reduced activity of the enzyme which synthesizes it. Some studies have detected improvements in mental performance after choline treatment.2 However, results of studies have been mixed. Choline and lecithin may only be useful in the initial stages of the disease. In a 1994 study, lecithin was given to patients with Alzheimer's disease in daily doses of 1000 mg for one month. Results showed slightly improved mental performance, and enhanced cerebrovascular blood flow.3

Cardiovascular disease

Choline helps to lower cholesterol levels, as a choline-containing enzyme helps to remove cholesterol from tissues. In a 1995 study, researchers gave lecithin supplements to 32 patients with high cholesterol and triglyceride levels. The dosage used was 3.5 g three times daily before meals. After 30 days of treatment, total cholesterol and triglycerides levels decreased significantly, and beneficial HDL cholesterol levels rose.4 Choline has also been used to lower homocysteine concentrations, another risk factor for cardiovascular disease. (See page 560 for more information.)

Other uses

Choline supplements (in the form of lecithin) have been shown to bring some benefits in the treatment of bipolar disorder (manic depression).5 Choline and lecithin are also used to treat liver damage and hepatitis. Supplements have also been used to treat asthma.6

Interactions

Severe folic acid deficiency causes secondary liver choline deficiency, and vice versa, in rats. Choline supplements reduce urinary excretion of carnitine.

1 Zeisel SH; Da Costa KA; Franklin PD; Alexander EA; Lamont JT; Sheard NF; Beiser A Choline, an essential nutrient for humans. FASEB J, 1991 Apr, 5:7, 2093-8

2 Franco-Maside A; Caamaño J; Gómez MJ; Cacabelos R Brain mapping activity and mental performance after chronic treatment with CDP-choline in Alzheimer's disease. Methods Find Exp Clin Pharmacol, 16: 8, 1994 Oct, 597-607

3 Caamaño J; Gómez MJ; Franco A; Cacabelos R Effects of CDP-choline on cognition and cerebral hemodynamics in patients with Alzheimer's disease. Methods Find Exp Clin Pharmacol, 16: 3, 1994 Apr, 211-8

4 Wojcicki J et al. Clinical evaluation of lecithin as a lipid-lowering agent. Phytotherapy Res 1995, 9, 597-99

5 Stoll AL; Sachs GS; Cohen BM; Lafer B; Christensen JD; Renshaw PF. Choline in the treatment of rapid-cycling bipolar disorder: clinical and neurochemical findings in lithium-treated patients. Biol Psychiatry, 1996 Sep, 40:5, 382-8

6 Gupta SK; Gaur SN. A placebo controlled trial of two dosages of LPC antagonist-choline in the management of bronchial asthma. Indian J Chest Dis Allied Sci, 1997 Jul, 39:3, 149-56

7 Dodson WL; Sachan DS Choline supplementation reduces urinary carnitine excretion in humans. Am J Clin Nutr, 1996 Jun, 63:6, 904-10