Soy is used to describe products made from soybeans, a legume native to northeastern Asia. For many years, vegetarians have consumed soy products as a way to replace proteins lost by not eating meat. Increasingly, Americans who are not vegetarians also have started to use soy products.

Soybeans can be found in many different foods. About 79 percent of fats consumed annually in the United States contain some form of soybean oil, according to the United Soybean Board. Soybean oil is usually high on the list of ingredients in commercial margarines, mayonnaise, salad dressings and vegetable shortenings.

Historically, the most popular soy products in United States were soy sauce and imitation bacon bits. In recent years, however, the soy industry has created a variety of products that are growing in popularity. There are four soy proteins used when making commercial soy products. Some of these proteins are available in powder, flake or pill form while others are added during production.

Organizations such as the American Heart Association (AHA) and the U.S. Food and Drug Administration (FDA) have issued reports in recent years about the health value of eating a diet rich in soy proteins. Unlike most meats, soy products are low in total fat and saturated fat. In addition, soy products have no cholesterol. Soy is also an excellent source of dietary fiber.

In 1999, the FDA allowed manufacturers of certain soy products to promote the health benefits of soy on their packaging labels. These health claims state that a low-fat, low-cholesterol diet containing at least 25 grams of soy protein a day may reduce an individual’s risk of heart disease. The FDA reviewed 50 human clinical trials as part of the health claim submission.

However, in early 2006, the American Heart Association (AHA) issued its finding from an analysis of 22 studies of the effect of soy on a person’s health. The AHA concluded that contrary to its earlier advocacy of high-soy diets, soy protein appears to have little or no effect on the risk factors associated with heart disease.