Although often associated with a vegetarian lifestyle, whey and soy proteins can actually be low-fat protein sources for anyone's diet. Soy comes from the soybean, a subtropical plant, while whey is a protein derived from cow's milk. Both are readily available in powder form, and soy is found in tofu and tempeh. According to MayoClinic.com, soy is a healthy, low-fat source of protein that has many potential health benefits. Bodybuilders and other athletes often use whey.
Muscle Endurance
A study published in the "Journal of the International Society of Sports Nutrition" in September 2010 investigated the effects of whey protein supplementation on muscle proteins. Participants were separated into groups that either received whey protein or a carbohydrate supplement. They were asked to perform exercises consisting of four sets of 10 repetitions at 120 percent of maximum voluntary contraction on the leg press, leg extension and leg flexion exercise machines. The whey protein group experienced greater knee extension strength, more muscle forces during recovery and less lactic acid build-up.
Improved Blood Lipids
High cholesterol levels are a major health concern and may put you at risk for heart disease. Whey protein, according to a study published in the "Journal of Medicinal Food" in September 2010, may improve blood lipid profiles. The study found that whey protein positively affected high-density lipoprotein, HDL, levels in the blood. HDL cholesterol is helpful; it keeps cholesterol from building up in your arteries.
Soy protein may also have a positive effect on blood lipid profiles. In February 2001, the "American Journal of Clinical Nutrition" released a study that found soy isoflavones made a small, but significant, improvement on the blood lipid profile in postmenopausal women with normal and slightly high cholesterol levels. Neither soy nor whey should be used as a treatment for high cholesterol, however; talk to your doctor if you are concerned about your cholesterol levels.
Better Bone Density
Soy isoflavones may have an impact on bone density after menopause. In a study released in the "Journal of Women's Health" in November 2004, one group of postmenopausal women was given soy isoflavones for six months and compared to a control group. The study found that among those given soy supplements, there was a 37 percent decrease in concentrations of a substance that is linked to bone resorption, or breakdown. Also, lumbar spine bone mineral density was greater in the soy isoflavone group than in the control group.
More Satiety
Whey protein may also promote satiety, potentially helping to reduce food intake. The "British Journal of Nutrition" featured a study in May 2010 that compared the effects of whey, egg albumin, turkey and tuna on satiety and insulin response. The results showed that whey protein produced a greater insulin response, reduced appetite and decreased food amounts at a buffet-style meal compared with the other proteins.
These results indicate whey protein may be a potential food for suppressing appetite, thereby promoting weight loss. These results are promising, but are not guaranteed. Talk to your doctor before taking whey protein for appetite suppression.
References
- "Journal of the International Society of Sports Nutrition"; Whey protein isolate attenuates strength decline after eccentrically-induced muscle damage in healthy individuals; M.B. Cooke; September 2010
- "Journal of Medicinal Food"; Evaluation of Biological and Biochemical Quality of Whey Protein; F.K. Haraguchi et al; September 2010
- "American Journal of Clinical Nutrition"; Soy isoflavones improve plasma lipids in normocholesterolemic and mildly hypercholesterolemic postmenopausal women; K.E. Wangen et al; February 2001
- "Journal of Women's Health"; Decreased bone resorption with soy isoflavone supplementation in postmenopausal women; L.S. Harkness; November 2004
- MayoClinic.com: Soy
- "British Journal of Nutrition"; The acute effects of four protein meals on insulin, glucose, appetite and energy intake in lean men; S. Pal and V. Ellis; May 2010
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