Lecithin is a type of fat called a phospholipid, consisting mostly of various saturated and unsaturated fatty acids, phosphoric acid, and choline. It is found in the cell membranes of all living things, and because it is present in both animal and plant tissue, it is easy to find sources of lecithin. Some of the best sources of lecithin in food are egg yolks, liver, peanuts, whole grains, milk, and soybeans. Lecithin is also often used as a food additive in processed goods, like ice creams and salad dressings. This kind of lecithin, sometimes called commercial lecithin, is commonly derived from soybeans.
Lecithin is not only available in food, but is also produced by the human body itself. It is present in the bile made by the liver, which helps metabolize fats. Usually, there is no need to take lecithin supplements because the lecithin made by the body and the natural lecithin in food provide enough for human health. There is no officially recommended daily intake for lecithin, though some dietary studies recommend a dose of 550 mg per day for men and 425 mg per day for women. Too much lecithin can lead to nausea, bloating, and diarrhea.
Egg yolk is one of the best sources of lecithin in food. Other animal sources include liver, milk, fish, fish eggs, chicken, and meat. Brains are another excellent source of lecithin. Good plant sources of lecithin include seeds, peanuts, wheat germ, olives, avocado, and cabbage.
As a food additive, lecithin is often used as a fat emulsifier, allowing oils and fats to combine with water. It is also used to prevent sticking, for example in nonstick cooking sprays, to give certain spreads a more pleasing texture, to give products a longer shelf life, and as a replacement ingredient to reduce the content of fat and eggs in baked goods. Ice cream, candy bars, margarine and salad dressings commonly contain lecithin. The lecithin in food additives is often derived from soybean oil and is also called soy lecithin. Sunflower oil is also often used to make commercial lecithin.
Lecithin is thought by some to have beneficial effects on the body. Some people think taking lecithin supplements can help improve brain function, counteract Alzheimer's, lower blood cholesterol, help the immune system, and promote heart health and liver function. However, scientific evidence does not support all these claims.