Food grade lecithin is a complex mixture of substances derived from the processing of soybean, corn, or safflower oil. Almost all of the lecithin of commerce is derived from soybeans. Phosphoglycerides, the major constituents of lecithin, are present throughout the body as chief components of cell membranes; significant amounts are also present in bile and plasma. The major phosphoglycerides found in soy lecithin can be catabolized and also synthesized de novo in mammalian systems. Commercial lecithin may contain up to 35 percent triglycerides; these compounds occur naturally in the diet and are also catabolized and synthesized in man. The average daily consumption of lecithin added to foods by manufacturers in 1970, based on the total amount reported to be used, was 92mg, amounting to about 1.5mg per kg body weight for adults. The corresponding figure for lecithin bleached with hydrogen peroxide was probably less than 4mg, about 0.07mg per kg. Thus, the lecithin added to foods amounts to only 2 to 10 percent of the 1 to 5g of phosphoglycerides consumed daily as natural constituents of the diet. A 2 year feeding study with rats given 1400mg lecithin per kg bodyweight daily (equivalent to a human dose of about 84g daily) showed no adverse effects except for an increased incidence of parathyroid hyperplasia. The parathyroid hyperplasia seen in the rats probably resulted form the increased phosphate load in the diet. No adverse effects have been noted in volunteers taking 20g or more of lecithin daily for several months. The Select Committe is not aware of any animal feeding studies with "food grade" bleached lecithin. Similarly, there appear to be no studies identifying the reaction products of lecithin bleached with hydrogen peroxide. However, in another report,the Select Committee reviewed studies of animals fed compounds which conceivably could form as a result of hydrogen peroxide oxidation of unsaturated fatty acids. Limited feeding studies indicate these compounds are not carcinogenic when given orally and are toxic only at doses orders of magnitude greater than could be expected from the addition to food of lecithin bleached with hydrogen peroxide.
No specifications are listed in the Food Chemicals Codex for the peroxide value of lecithin bleached with hydrogen peroxide; the Select Committee believes such specifications should be developed.
In the light of these considerations, the Select Committee concludes that: There is no evidence in the available information on lecithin and lecithin bleached with hydrogen peroxide that demonstrates or suggests reasonable grounds to suspect a hazard to the public when they are used at levels that are now current or that might reasonably be expected in the future.