Soy and whey can be added to the diet in many forms, including health bars, protein drinks and powders. Soy protein might be most beneficial in cardiovascular health. Whey protein is good for reducing body fat while maintaining lean body mass. When choosing which protein to use, compare soy vs. whey according to your specific exercise, dietary or health goals.
Nutrition
Soy and whey contain antioxidants that protect against free radical damage and help the immune system fight disease. Both supply essential amino acids, minerals and vitamins, although their sources are completely different.
Soy protein, made from soybean pods, is produced in various ways: refined protein isolate; protein concentrate; and textured soy, which is often used in vegetarian products as a meat or dairy replacement. Because of its ability to reduce calcium loss and increase bone mineral density, soy might reduce osteoporosis.
Whey protein is made from cow's milk and is a byproduct of cheese-making. Forms of whey include protein isolates, protein concentrate and hydrolyzed whey, which contains little or no lactose, carbohydrates or fat. Whey is absorbed quickly in the body and contains 50 percent more leucine than soy, which assists with protein synthesis needed to help muscles grow and recover from stress or exercise, according to the Whey Protein Institute.
Protein
Protein, which is essential for healthy skin, bones, muscles and tissue, is comprised of nearly two dozen amino acids, many of which are "essential" because they cannot be made by the body so must come from food. Most vegetable proteins are incomplete proteins but soy and whey contain all 10 essential amino acids. The PDCAAS, or protein digestibility corrected amino acid score, is a method of assessing protein quality based on amino acid content and digestibility. Whey protein has the highest possible score of 1.0; soy has a score of .91 to .92, according to the American Council on Exercise. Biological Value, or BV, is a rating of the bioavailability of the protein. Whey has the highest score of 100 while soy is 74. This means that whey contains more protein than soy, and absorbs and digests the protein more easily into the bloodstream.
Weight and Body Mass
If you are a bodybuilder or strive to enhance your athletic performance, soy and whey protein offer similar results on producing lean muscle mass. A study at the Ohio State University in Columbus compared the ability of soy and whey to promote muscle gain. Findings were that whey and soy protein both showed a gain in exercise-induced lean body mass in comparison with the control group. However, soy was superior in protecting antioxidant function, as published in the Nutrition Journal in 2004.
Cholesterol
Because soy doesn't contain any cholesterol, it can help protect against the risk of heart disease. A 1995 study examined soy and its association with serum lipid concentrations in the body. Conclusions, which were published in the American Journal of Clinical Nutrition, found intake of soy protein lowered levels of total cholesterol, including LDL, the "bad" cholesterol while maintaining levels of HDL, the "good" cholesterol.
Menopause
Many women turn to soy to relieve the symptoms of menopause. Research by the Agency for Healthcare Research and Quality concluded that soy was beneficial in reducing hot flashes in trials with post- and peri-menopausal women. Phytoestrogens in soy might be a viable alternative to estrogen therapy to treat symptoms of menopause. However, the study warns that the estrogen-like effect of soy may promote tumor recurrence in breast cancer survivors.
References
- Soya: What is Soy Protein: Categories
- North Carolina School of Pharmacy; What is Soy?; A. Solomon, J. Baker
- Whey Protein Institute: Benefits of Whey Proteins
- American Council on Exercise: Current Supplement Research Overview: Which Protein is Best?
- MyFitnessPal: Calories in Food
- "Nutrition Journal": Soy Versus Whey Protein Bars: Effects on Exercise Training Impact on Lean Body Mass and Antioxidant Status; Eric C. Brown, et al.; 2004
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