Lecithin is a complex fat-like substance found in the cells of all living organisms. It is also used in the food industry as an emulsifying agent, and is isolated from egg yolk and soybeans for this purpose. You will certainly find it wherever dietary supplements are sold, because it has been promoted as a natural remedy to combat atherosclerosis, improve memory, and fight Alzheimer's disease. There is no scientific evidence that it has any of these beneficial effects, nor that it promotes weight loss (supposedly by breaking down fat and enabling the body to flush it out.)
Claims that lecithin can lower cholesterol are based on the fact that it contains polyunsaturated fatty acids. But, again, I've seen no evidence to support this. I recommend lecithin only to patients with multiple sclerosis as a way of strengthening nerve sheaths, which are the targets of that disease and are composed of myelin, a derivative of lecithin.
Supplemental lecithin is harmless, but if you want a natural product to lower cholesterol, forget it and consider using red rice yeast extract. It is a source of naturally occurring statins, works as well as pharmaceutical statins, and has a lower incidence of side effects. (For more information, go to www.drweil.com and type "red rice yeast" in the search box.)
No matter what supplement or drug you use for cholesterol control, be sure to get at least 30 minutes a day of aerobic exercise and reduce the amount of saturated fat and trans-fats in your diet. Other beneficial lifestyle changes include drinking green tea, eating one clove of garlic per day (diced or crushed in food), and consuming more soluble fiber (such as oat bran), foods rich in omega-3 fatty acids (good sources include salmon, sardines and walnuts; or supplemental fish oil), and plenty of colorful fruits and vegetables.
Andrew Weil, M.D.