Comprised of both choline and inositol, lecithin is a fatty product that plays pivotal roles in the overall health and integrity of cellular membranes. Nearly 30 percent of the brain’s dry weight is composed of lecithin. Lecithin also represents nearly 70 percent of fat located within the liver. Lecithin is an essential nutrient, which is vital to many basic biological processes. The production of bile, and transportation of both fats and cholesterol, remain among lecithin’s more important physiological roles.
In actuality, the term lecithin has two separate meanings. Its varying definitions are strictly dependant on the nutrient’s method of preparation. When it is used commercially, “lecithin” refers to a complex mixture of neutral and polar lipids. When lecithin is used chemically, it is defined as a purified form of phosphatidyl choline (PC). Nutritional supplements labeled as “lecithin” contain approximately 20 percent phosphatidyl choline. 
As mentioned, lecithin, or phosphatidyl choline, is vital for many critical cell functions. Tasks such as energy production within the cell, intracellular communication, signal transduction, and information transfer from DNA to RNA proteins, are all solely dependant on adequate levels of phosphatidyl choline. This has proved to be of great relevance, as various physical and neurological disorders are thought to be associated with the damage to specific cellular membranes.
PC may also be metabolized into choline, fatty acids, and/or glycerol. Choline is the precursor to acetylcholine, an important neurotransmitter responsible for normal brain functioning. Because of choline’s neurological importance, it is considered critical in the brain development of infants, and may be essential in adults during periods of illness, injury, or stress as well. This may provide an explanation as to why lecithin is often referred to as “brain food.”
Vegetables represent the most popular and most bioavailable sources for dietary lecithin. Lesser amounts may also be found in certain animal and microbial sources. Soybeans, sunflower, rapeseed, grains, wheat germ, and yeast, are the most frequently used plant sources for commercialization. Other sources of lecithin include; legumes, peanuts, and egg yolk. Eggs naturally contain upwards of 72 percent phosphatidyl choline.
Preliminary results from various clinical trials suggest that lecithin may be an effective agent in the treatment of various types of alcohol and non-alcohol induced liver damage. [2, 3] For many individuals suffering from liver disorders spawned by toxins, viruses, and disease, phosphatidyl choline has proven more tolerable than choline when used for the enhancement of proper liver functioning.
In one particular mammalian study, a 60 percent phosphatidyl choline supplement was used on test subjects with diets high in alcohol consumption. Both liver fibrosis and cirrhosis were prevented in the test groups receiving a PC supplement. Lecithin may provide certain heptoprotective effects.  Its protective benefits may also be equally effective in organs adversely affected by nonsteroidal anti-inflammatory drug (NSAIDs) treatments.
Certain neurological conditions may also be improved by supplemental lecithin. Phosphatidyl choline has been used in cognitive disorders (i.e. Alzheimer's disease and tardive dyskinesia) with varying success. [6, 7] The overall success of these preliminary studies may point back to the decreased ability for sufferers of these conditions to synthesize acetylcholine. Research continues, but by helping to increase acetylcholine levels in the brains of these individuals, phosphatidyl choline/choline supplementation may provide some benefit in the areas of memory restoration and neurological functioning.
Lecithin has also been shown to bind with cholesterol, thereby providing for a reduction in the pure cholesterol found within the bloodstream.  By effectively lowering moderately elevated blood cholesterol levels, lecithin may also lower homcysteine levels; both of which are thought to contribute to an increased risk of cardiovascular disease.
Past study has also suggested that lecithin may also be used to treat psoriasis, some forms of cancer, and may even improve athletic performance. [9, 10] These claims, however, remain unsubstantiated and future clinical applications are warranted.
Although the Food and Nutrition Board is considering the establishment of a recommended dietary intake for lecithin, a current recommended intake or tolerable upper level intake does not exist. Medical experts often agree that the majority of Americans are deficient in both choline and lecithin, and that the dietary supplementation of lecithin containing products is sensible.  Several delivery forms are available for supplementary lecithin, including loose granules, capsules, and liquid concentrates. Standard dosages range from 1-10 grams per day.
|Adults and Teenagers||Children up to age 12|
|Dosage||3–9 grams daily||Not Applicable|
There are no reports of overdose or toxicity resulting from prolonged and elevated dosages of lecithin-based supplements. Studies with dosages ranging from 25 - 40 grams per day , administered over a period of several months have deemed lecithin safe and non-toxic.  Lecithin sensitive individuals may, however, develop gastrointestinal disorders, weight gain, headache, dizziness, rash, or even a “fishy” body odor. (This odor is the result of the choline present in many lecithin supplements)
There have been no reported deficiencies of this nutrient. The probability of one developing a lecithin deficiency is extremely minimal.
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