Functional Foods

Labels: functional food, isoflavone, prebiotic, probiotic, soy, Tara Gidus

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Soy Wise

This post is in response to a question I received from someone wondering about the difference between soy protein isolate and concentrate. I thought it was an interesting question and thought I would give some background to soy in general and address the issue originally asked about as well.

Potential soy health benefits
Soy protein has been highly studied in medical research for many years. The main research has surrounded heart health. In 1999, the FDA approved a health claim for food labels that states, "Diets low in saturated fat and cholesterol that include 25 grams of soy protein a day may reduce the risk of heart disease. One serving of (name of food) provides __ grams of soy protein."

Soy is a “complete protein,” which means it contains all of the essential amino acids. It is the only vegetarian source of complete protein. This means that vegetarians can use soy-based products and be assured that they are getting a high quality protein as a substitute for animal proteins.

Soy contains isoflavones which are sort of like a weak form of estrogen. Researchers are investigating whether including more soy in the diets of girls during teen years may help to reduce risk of breast cancer later in life. In addition, menopausal women may benefit from these isoflavones in soy to reduce hot flashes.

Studies are under way for the potential benefits for osteoporosis, breast cancer, colon cancer, and prostate cancer.

Controversy
As with most foods, soy has it’s share of controversy. Recent research suggests that the data may not be as strong as originally thought for the cholesterol lowering effect of soy. Concern has also been raised for people taking supplements of isoflavones because they are taken in very high concentrations. Soy infant formula and the effect of soy on the thyroid have also been recent subjects of further investigation. No firm conclusions have been established for any of these areas to date.

Isolate, Concentrate, and TSP
Soy protein isolate is the most highly refined form of soy protein. It is 90% protein and is used in things like nutritional supplements (bars, shakes, powders), meat analogs (vegetarian forms of meats like veggie burgers), and infant formula.

Soy protein concentrate is very similar but is 70% protein and contains some carbohydrate and fiber from the soybean. It is found in cereals, pasta, and baked goods.

Texturized soy protein, or TSP, is made from soy protein concentrate and comes in a dried, granular form. When it is rehydrated it is similar to ground beef in texture. It is high in protein and also has fiber. Many people like to replace ground beef with TSP or add TSP to ground beef to reduce the fat and add soy protein to a meat dish.

Any of these forms of soy protein, isolate, concentrate, or TSP, are a great way to get more soy protein into your diet.


For more information on Soy, click here.


Photo courtesy of istockphoto.

Labels: soy, Tara Gidus

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