Lecithin is a lipid material composed of choline and inositol and it is found in all living cells as a major component of cell membranes, which regulate the nutrients entering and exiting the cell. It plays a major role in most biological processes, from breathing to energy production to nerve transmission. Lecithin acts as a supplier of choline, which is needed for cell membrane integrity and to facilitate the movement of fats in and out of cells. It is also a component of the neurotransmitter acetylcholine and is needed for normal brain functioning, particularly in infants. Although the human body can synthesize choline, additional amounts from a daily diet are considered essential under certain circumstances.