Inadequate Intake?
Back in the 1970s, the average American diet contained about 6,000 mg of lecithin per day. Today, intakes are less because we've cut back on fatty foods--the foods that are also rich in lecithin. Eggs, organ meats and other meats are good sources, whereas grains, fruits and vegetables are poorer sources.

Eliminating an egg from the average daily diet reduces the day's total lecithin intake by a third, and that has scientists worried. Richard Wurtman, M.D., a neuroscientist at the Massachusetts Institute of Technology, in Cambridge, Mass., and other experts say many people are not getting enough lecithin and choline.¹

One tablespoon of lecithin granules provides about 1,725 mg of phosphatidylcholine and 250 mg choline, a little less than the content in an egg. The "commercial lecithin" in most lecithin supplements is a mixture of phosphatidylcholine and other phospholipids extracted from soybeans. Commercial lecithin in granular form contains about 23 percent phosphatidylcholine; lecithin capsules provide about 15 percent. One capsule provides about 180 mg of phosphatidylcholine and 25 mg of choline; 10 or 12 capsules would match the amount of lecithin and choline in a tablespoon of granules or in an egg.

Supplemental choline also can be taken in the form of choline salts, choline bitartrate and choline chloride, but lecithin appears to provide a more bioavailable, timed-release source. When equal amounts of choline are consumed in lecithin or in choline salts, lecithin sustains plasma choline at a higher level for a longer time, and "lecithin may be more effective than choline chloride as a therapeutic agent."²

More choline is available from lecithin than from its salts, apparently because less of lecithin's choline is converted by intestinal bacteria to an unusable form called trimethylamine. Only about one-third of the choline from lecithin is lost this way³ versus about 60 percent for choline salts.⁴ To add insult to injury, high amounts of trimethylamine in the gastrointestinal tract can produce an offensive, fishy odor.

Commercial lecithin, phosphatidylcholine, choline bitartrate and choline chloride are all generally recognized as safe by FDA.

Lecithin At Work
In many of the studies that convinced nutritionists that choline is an important nutrient, lecithin appears to reduce the risk of cardidovascular disease (CVD) in several ways: by contributing cholesterol-lowering polyunsaturated fats, inhibiting intestinal absorption of cholesterol, increasing the excretion of cholesterol and bile acids, and favorably affecting lipoprotein profiles.

In one study, 32 people with high blood lipids were given 10.5 g of commercial lecithin for 30 days. Their average total cholesterol and triglycerides decreased by an impressive one-third, LDLs decreased by 38 percent and HDLs increased by 46 percent. The researchers concluded that "lecithin ... should be administered for the prevention and treatment of atherosclerosis."⁵

The choline portion of lecithin may also reduce CVD risk by helping to metabolize homocysteine, an amino acid strongly linked with increased CVD risk. Homocysteine is made in the body from the amino acid methionine and can be broken down by three possible pathways that involve vitamin B6, folic acid and vitamin B12, or choline. Enzyme defects in any of these pathways, deficiencies of the corresponding vitamins, as well as various disease states and drug therapies can elevate plasma homocysteine levels.

People with high blood homocysteine levels have been successfully treated with vitamin B6, choline (or its metabolite, betaine) and folic acid. Six grams per day of betaine significantly reduced homocysteine levels in patients both nonresponsive⁶ and responsive⁷ to vitamin B6 therapy.

Lecithin is abundant in nerve cell membranes and is required for nerve growth and function. Additionally, choline helps generate methyl groups, which are important in activating DNA. Because of these and other functions, choline is widely recognized as important in brain and mental development of both fetus and infant. Not surprisingly, choline in the mother's bloodstream has been concentrated 14-fold by the time it reaches the fetus⁸ and is concentrated more than 100-fold in mother's milk.⁹ Thus, the requirement for choline appears to be especially high in women during pregnancy and lactation. Infant formulas approved by FDA are required to contain levels of choline comparable to those in human milk.

Low intakes of folic acid and high levels of homocysteine in pregnant women are thought to increase the risk of neural tube defects (NTDs), devastating abnormalities affecting 2,500 to 3,000 babies born in the United States each year. To help prevent these defects, CDC in Atlanta recommends all women of child-bearing age take 400 ug per day of folic acid, and FDA now requires folic-acid supplementation of a broad variety of grain foods.

NTDs are complex disorders, probably involving other nutrients as well. Because folic acid and choline work together, an inadequate choline intake might "use up" folic acid and raise homocysteine levels. This effect has been shown in animals.¹⁰ Thus, choline may play a role in preventing NTDs, although that remains to be proven in further research.

Lecithin and choline serve other functions in reproduction and development. Another choline phospholipid, platelet-activating factor, is involved in implanting the egg in the uterine wall, fetal maturation and inducing labor.¹¹ In test-tube studies, lecithin restored normal structure and movement to abnormal sperm cells¹² and nearly doubled the ability of sperm to enter and fertilize an egg.¹³

Numerous animal studies show a choline-deficient diet promotes liver cancer. The disease begins with early signs of fat buildup in the liver because lecithin is required to make very-low-density lipoproteins (VLDLs), the liver's major fat exporter. If choline deficiency continues, a fatty liver is followed by cell death, collagen buildup (fibrosis), cirrhosis and cancer. Extra choline is shown to protect against liver cancer in mice exposed to a cancer-causing substance.¹⁴ A number of lecithin-like compounds are being studied in humans as potential cancer therapies.

Lecithin and choline are important to liver function in humans as well. Healthy adults fed a semisynthetic diet devoid of choline for a few weeks showed early signs of liver dysfunction.¹⁵ Individuals fed intravenously for long periods of time developed a fatty liver and liver cell damage. Supplemental lecithin reversed liver fat in these patients.¹⁶

Research by Charles Lieber, M.D., and colleagues at the Alcohol Research and Treatment Center, V.A. Medical Center, Bronx, N.Y., suggests lecithin may protect the liver in other ways besides providing choline. In two studies, baboons were fed diets high in alcohol with or without added lecithin for up to eight years. None of the supplemented animals developed liver fibrosis or cirrhosis, but about 80 percent of those not given lecithin did.^17,18 An earlier study showed that supplemental choline did not protect the liver against alcohol.¹⁹ Test-tube studies showed lecithin increased the breakdown of collagen, which builds up in alcohol-induced fibrosis and cirrhosis. Lieber's group is currently conducting a multicenter clinical trial of lecithin supplements in alcoholic patients.

Better Memories

A good deal of evidence from animal studies shows lecithin and choline improve memory and learning. When choline was fed to pregnant rats, their offspring showed significantly better memory in maze tests than rats whose mothers were not fed choline.²⁰ The improved memory was maintained at a level comparable to that of much younger rats even after the rats grew old. The beneficial effect probably relates to lecithin's function in nerve membranes and to the need for choline to make the neurotransmitter acetylcholine, which enables signals to go from nerve to nerve.

Human studies suggest lecithin and choline may also benefit memory. In one, investigators gave 61 healthy older adults (aged 50 to 80 years) either 2 tablespoons of lecithin or a placebo for five weeks. By the end of the study, memory test scores of the lecithin group improved significantly, exceeding those of the placebo group. The lecithin group also reported a 48 percent decrease in memory lapses. The investigators concluded that "the cost of lecithin is so low, the negative side effects so minimal and the potential benefits so positive, that we would recommend ... all persons experiencing memory problems ... (try) lecithin granules as food supplements."²¹

Because nerves also carry signals to muscle fibers, it is not surprising that studies show lecithin and choline supplements improve the performance of some physical activities. In one of the first studies in this area, researchers found plasma choline levels of Boston Marathon runners dropped by about 40 percent during the race.²² Significant drops have also been shown in 20-mile runners, swimmers and triathletes. Choline supplementation prior to activity appears to prevent the decline of plasma choline and, in many cases, to improve performance.²³

In one double-blind crossover study, long-distance runners ran a 20-mile race in an average 158.9 minutes after taking a placebo; they improved their average time to 153.7 minutes after taking 2.8 g of choline chloride.24 Given that races can be won or lost by seconds, five minutes is a large improvement.

Choline supplementation also improved swimmers' race times and decreased fatigue. In another study, choline increased feelings of vigor in swimmers and college basketball players. Short-duration, less-intense activities, however, do not appear to reduce blood choline levels or to benefit from supplementation.

Choline is not included in the most recent (1989) RDAs, which were determined before much of the evidence described here was available. The Food and Nutrition Board, which determines RDAs, plans to create several committees to reassess the RDAs for various nutrients. One of the first such committees is developing recommendations for choline, folic acid, vitamin B12 and methionine.

Janet King, Ph.D., a member of the board and director of the USDA's Western Human Nutrition Research Center in San Francisco, discussed new approaches to developing RDAs at a 1996 conference and noted, "The Food and Nutrition Board recognizes that there are a number of nutrients important to health with no currently designated RDAs, such as choline and fiber."²⁵

Choline is an essential nutrient for humans. It is involved in methyl-group and homocysteine metabolism and, as a component of compounds such as lecithin, sphingomyelin, platelet-activating factor and acetylcholine, it serves many diverse functions. Lecithin and choline play important roles in lowering cardiovascular disease risk, in reproduction and development, and in liver health and function; they may also improve memory, learning and physical performance.

How much lecithin should one take as a supplement? A reasonable amount is 1 or 2 tablespoons of granular lecithin a day, which supplies 1,725 mg to 3,450 mg of phosphatidylcholine and 250 mg to 500 mg of choline. These amounts probably are 30 percent to 60 percent of what people obtain from their diets today.

Granular lecithin has a mild, nutty flavor and can be sprinkled on cereal and combined with other foods. Because it's an emulsifier, lecithin can make gravies and sauces smoother, can partly substitute for fats and oils in baked goods, and is the main ingredient in antistick cooking sprays. Lecithin supplements are preferred over choline salts because lecithin appears to provide a longer-lasting timed-release source of choline--without the offensive, fishy odor.

22. Conlay, L.A., Wurtman, R.J., et al. "Decreased plasma choline concentrations in marathon runners" (correspondence), N Engl J Med, 315: 892, 1986.

23. Sandage, Jr., B.W. Sabounjian, L.A., et al. "Choline compounds and performance in humans," NIH workshop on The Role of Dietary Supplements for Physically Active People, Bethesda, Md.: June 1996.

24. Sandage, Jr., B.W. Sabounjian, R.N., et al. "Choline citrate may enhance athletic performance." Physiologist, 35: 236a, 1992.

25. King, J.C. "Recommended daily intake for choline and choline phospholipids: Should there be a dietary reference intake for choline?" AOCS annual meeting and expo, Indianapolis, Ind.: May 1996.