Isolates, according to dictionary sources, are "pure substances" (actually categories of substances) isolated from a more complex mixture of substances. Thus, take a food item and remove nearly everything from it but one type of chemical, such as protein, and what remains is an isolate--a protein isolate. Interest in protein isolates is on the rise, as is their manufacture for product ingredients and food supplements. Among the most common of these isolates are whey isolate, soy isolate and wheat isolate. These are of special interest to bodybuilders but are also of interest to the "health conscious."
Whey Protein Isolate
Whey is the soluble portion of milk that remains after milk has been coagulated. After processing whey to remove fat and lactose, the remaining isolate is more than 90 percent protein. The American Physiological Association says whey isolate possesses some "some extraordinary nutritional properties."
Soy Protein Isolate
Soy isolate is made from defatted soy flour, from which carbohydrates are also removed. It has a minimum protein content of 90 percent and is moisture-free. It is added to foods for texture and protein control and to act as an emulsifier and for moisture retention. It is the basic ingredient in soy infant formulas.
After flour has been made from wheat, the remaining material is termed wheat protein isolate. It is a slightly yellowish powder. It is a particularly useful ingredient in baking because it adds texture, softness and "freshness." It has a higher level of protein (about 85 percent) and solubility than wheat gluten.
Whey protein isolate is popular among resistance bodybuilders. Among other cited benefits are an improved percentage of body fat.
Soy isolate, once deemed inferior to whey isolate, is now being reconsidered, because it is superior in building lean muscle mass. In addition, the idea that soy isolate lowered testosterone level in men appears to have been false. Soy offers added nutrition and may possibly fight some cancers.
Wheat isolate offers a few advantages. It has a higher glutamine/glutamic acid level than the other isolates, and it is not animal-based.
Possible Health Issues
Some question the safety of using soy isolate. Several websites, such as SoyOnlineService and AlkalizeForHealth, indicate the FDA never granted GRAS (generally recognized as safe) status to soy protein isolate.
Yet another claim is that processing soy to produce the isolate involves aluminum utensils and exposure to chemicals that leach aluminum into the isolate.
Although these fears may or may not be true, the American Heart Association has asked the Food and Drug Administration to consider its view on the use of soy protein, because of an apparent lack of corroboration on some of the health benefits currently attributed to soy.