Lecithin is also known as phosphatidylcholine. It is a fat, or lipid, material found in the membranes of all living cells and functions to regulate the entry and exit of cellular nutrients. While lecithin is found in many foods, either naturally or as a food additive, it is also sold as a dietary supplement. However, liquid lecithin in dietary supplement form is not necessarily simply phosphatidylcholine; it is often a mixture of inositol, choline, phosphatide, phosphatidylcholine, as well as other compounds.
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Chemistry of Lecithin
Pure lecithin is composed of phosphatidylcholine. Phosphatidylcholines are a group of phosopholipids that also contain choline. Phospholipids are involved in the lipid bilayer of cells, regulating the nutrients that can enter and exit the cell. In addition, choline is involved in the manufacture of acetylcholine, a neurotransmitter. Inositol is a carbohydrate that is also involved in cell signaling, specifically insulin signal transduction and may also be involved in gene expression.
Lecithin is usually the most abundant phospholipid in both plant and animal cells. It can make up almost 50 percent of the total phospholipid content. In humans, lecithin is the principal phospholipid circulating in plasma, being an integral component of HDL cholesterol.
Sources of Lecithin
Lecithin is found in a variety of foods including egg yolk, soybeans, grains, wheat germ, fish, legumes, yeast and peanuts, as well as liver, cauliflower, grape juice and cabbage.
In addition, Lecithin is used as a food additive, functioning as an emulsifier, thickener, stabilizer, moisturizer and mild preservative. It is added to baked goods such as breads, cakes and cookie dough as an anti-caking, pan release and moisturizing agent, and as an emulsifier for products such as mayonnaise, margarine, shortening, sauces, gravies, soups and salad dressings. To prevent crystallization, as well as acting as an emulsifier, lecithin is added to chocolate and caramels, and as a wetting, dispersing and emulsifying agent, it is added to powdered products such as cake mixes, cocoa powder and instant pudding mixes.
As a dietary supplement, lecithin available in a variety of forms and strengths, including liquid, capsule and granular form. Most often sourced from organic soybeans, dietary supplements of lecithin are highly filtered and usually contain less than 35 percent phosphatidylcholine.
Lecithin Supplementation Claims
Liquid lecithin as a dietary supplement is advertised as having a variety of health benefits including weight loss, improvement of memory and cognitive functions, improvement of poor nutrition and anemia, diabetes, neurologic disorders, cardiovascular health, improvement in energy and physical performance, assistance with Vitamin A, D, E, and K absorption, psoriasis, gallstones, easing digestion and improving overall health.
Unfortunately, there really is no scientific evidence to support these claims. The theory behind the claims is that because lecithin is an emulsifying agent, it can break down fat and disperse it in the blood stream helping to flush it out of the body. In fact, lecithin may increase weight gain as it is a fatty acid and is highly caloric.
Lecithin is involved in producing acetylcholine. Acetylcholine is a neurotransmitter involved in cell signaling between brain cells. Acetylcholine production is compromised in Alzheimer's patients. According to Vanderbilt University, many studies have been administered to test lecithin's effect on Alzheimer's disease, with the expectations that lecithin will help produce more acetylcholine and therefore improve memory. However, while both lecithin and choline itself have been tested, they do not appear to have this effect.
Lecithin supplementation has shown to be highly successful in treating choline depletion. Patients taking niacin or nicotinic acid to treat high cholesterol often experience choline depletion. Lecithin supplements, and or increasing lecithin in the diet has been shown to ameliorate this issue.
Low doses of 10 to 30 grams per day of lecithin supplements do not appear to cause any major side effects, according to Vanderbilt University. However, higher doses can cause gastrointestinal problems, diarrhea, weight gain, a rash and headache, nausea, vomiting, dizziness and a fishy body odor. These effects are not seen with phosphatidylcholine supplementation, indicating that other ingredients of lecithin supplements contribute to the side effects.
Lecithin supplementation can lead to increased acetylcholine levels, which can worsen symptoms of depression.