Soy lecithin is a nearly ubiquitous food additive, found in a great many processed foods and personal care products on the market today. A few commonly-used examples include cooking spray oil, salad dressings, mayonnaise, margarine, ice cream, bread, tortillas, cookies, soups, chocolate, candy, chewing gum, protein and granola bars, tea bags, cough drops, skin lotion, lip balms, cosmetics, and medicines, as well as paints, textiles, lubricants, waxes and animal feed.
Even if food products don’t specifically list soy lecithin, they may be marked “Contains soy.”
Chemically, soy lecithin is an emulsifier, meaning that it takes polar and non-polar ingredients that would not normally mix (such as oil and water), and helps them to homogenize and remain mixed. This is due to the fact that the lecithin molecule has both hydrophilic (water-loving) and hydrophobic parts. Soy lecithin is particularly useful in stabilizing oily mixtures such as salad dressings and mayonnaise. It serves the same purpose in candy bars to keep the fatty cocoa butter mixed with the cocoa and dairy – to enable a smooth, velvety mouth feel. It also helps prevent the crystallization of sugar in chocolates.
Soy lecithin also functions as a surfactant to reduce the surface tension of water. For this reason it is added to foods to allow substances to mix more smoothly in water without clumping. In baking, soy lecithin is used as a conditioner to make the dough easier to work with. Similarly, it is found in some tea products – to prevent the ground tea from clumping. It functions as a thickener in soups.
Soy lecithin has lubricant properties, and is used as a moisturizer in lip balms, cosmetics, lotions, and many other personal care products on the market.
Soy lecithin is rich in the essential nutrient choline, and used as a dietary supplement to support liver function, neurotransmission, cardiovascular health, muscle development and healthy metabolism. There is some research indicating that soy lecithin helps lower cholesterol levels.
In modern innovative cooking techniques such as molecular gastronomy, soy lecithin has found new uses — to make light, airy foams and mousses out of nearly any water-based liquid – such as coffee. Here it acts as a stabilizer to make the foam last longer. See: How to make a soy lecithin foam using an inversion blender.
What exactly is lecithin? The molecular formula of lecithin is C35H66NO7P. Lecithin, found in the cells of living organisms, was first discovered by the French chemist Maurice Gobley in 1850; it is an oily substance, a mixture of phospholipids and oil. Chemically, a phospholipid has two hydrophobic fatty acid chains and a hydrophilic end consisting of a phosphate group — linked by a glycerol molecule.
Lecithin can be derived from soybean oil or egg yolks; it is also present in peanuts, wheat germ and canola oil. Soy lecithin is most widely used because it is inexpensive, a byproduct of soybean oil production (soybean prices are kept low, partly due to federal price supports).
Are there valid concerns about soy lecithin? Soy itself is a common allergen, but the soybean allergen is associated with the protein fraction of the bean. Since the majority of the protein is removed during the processing of soy lecithin, it does not typically induce allergic reactions. Yet, some claim to have allergies even to soy lecithin — and try to avoid even products such as chewing gum.
Many people express concerns about genetically modified soy – or remnants of the agricultural pesticides used while growing soybeans. There are some indications that soy may exhibit estrogenic effects, acting as an endocrine disruptor. This certainly warrants further research. In addition, there have been studies on the exposure of pregnant rats to soy lecithin, which may be associated with sensorimotor deficits in offspring.
Lecithin is approved for human consumption by the U.S. Food and Drug Administration under the status GRAS — “Generally Recognized As Safe”. The European Union allows it as a food additive.
Should you worry? Unless you never touch processed food, you will simply not be able to avoid soy lecithin and other additives. Small amounts are probably not going to harm you. Our concern should be over the large number of products that we regularly consume or use on our body which contain soy lecithin. When necessary, seek alternatives. Consumers need to be informed — and get in the habit of reading labels.
For more information: Soy Lecithin Fact Sheet