Many studies show that protein needs are greater for people who exercise. While it’s possible to get more protein from food alone, it’s certainly not easy or convenient. As a result, many people rely on protein supplements to meet their increased protein requirements.
Over the past few years, whey protein products have become increasingly popular with anyone who wants to lose fat and build muscle. Soy protein products have also been popular for individuals who want to lose weight and lower cholesterol. This article is designed to review the strengths of each of these proteins and help you decide which one is right for you.
The first point to make is that both whey and soy protein are complete proteins. This means they contain all the essential amino acids the body needs each day. They are both excellent protein sources that are low in fat and cholesterol content. There is emerging scientific evidence that both whey and soy protein can enhance the body’s immune system. Secondly, they are both easily digested. They do, however, have properties that make them unique.
Whey protein is a mixture of some of the proteins naturally found in milk. Milk contains two primary proteins: casein and whey. Whey proteins are available in three forms. Whey protein isolate is the purest form of whey protein and contains 90-95% protein. It contains little fat and little lactose. Whey protein concentrate is about 80% protein, and as the amount of protein decreases, the amount of fat and lactose increase. Hydrolized whey is the other form. The process of hydrolysis breaks the protein down into smaller segments called peptides. Hydrolized whey has the lowest potential for allergic reactions for those people allergic to milk products; that would be the only reason to use this form.
The proteins found in whey are some of the most rapidly digested proteins known. Many bodybuilders find whey proteins are more compatible for their digestive systems. Whey proteins also have the ability to stay in the body longer than most proteins. Whey protein also is an excellent source of branch-chain amino acids (BCAAs).
The fact that whey protein provides an excellent supply of BCAAs is important to athletes. The amino acids isoleucine, leucine and valine form the BCAAs. The requirements of these key amino acids are increased during exercise. This is because they have the ability to be directly taken up by the muscle and used as an alternative energy source. No other amino acids or proteins work this way. The muscle is able to work longer before fatigue or injury occurs. The BCAAs are also contributing factors in the maintenance and repair of muscle tissue. Whey protein supplements are an effective way to meet the increased protein requirements of serious athletes and also promote good muscle growth and health.
Soy protein comes from a plant. Unlike most plant proteins, soybeans contain all the essential amino acids. Soy is safe for lactose intolerant people and has an extremely low allergic potential. Soy protein is low in calories, fat and cholesterol. It is clearly an essential protein source for vegetarians.
The most interesting aspect of soy protein comes from the scientific and epidemiological studies done on cultures whose diet contains 25 grams or more of soy protein each day. These people have some of the lowest rates of heart disease, cancer, osteoporosis and menopausal symptoms in the world.
Soy protein contains unique and complex molecules called isoflavones. People who do not eat soy have virtually no isoflavones in their diet. Many of the health benefits related to soy are due to these isoflavones.
Isoflavones are powerful antioxidants. They have a molecular structure similar to estrogen but exhibit a much weaker effect on women and no effect on men. Studies have shown that isoflavones are responsible for the reduction of menopausal symptoms in women and for the reduced incidence of osteoporosis in women who consume soy protein regularly. There are also studies that concluded a soy protein rich diet produced lower rates of breast, colon and prostate cancer. We now know that soy protein exerts several heart protective effects. First, it decreases LDL-cholesterol levels. Secondly, it tends to increase HDL-cholesterol levels. Third, soy isoflavones have antioxidant properties, which protect LDL from oxidation. Fourth, soy isoflavones have favorable effects on blood vessel function.
On October 26, 1999, the Food and Drug Administration authorized use of health claims about the role of soy protein in reducing the risk of coronary heart disease on labeling of foods containing soy protein.
The final analysis of these two proteins is very positive. Both are high quality proteins that are excellent alternatives to red meat. The more intense athlete will need to add whey protein to his diet. Women will find special advantages to soy. Certainly there is abundant evidence that a combination of both is a great strategy.
- Soy Protein and Risk for Coronary Heart Disease by James W Aanderson, MD. Professor of Medicine and Clinical Nutrition Univ. Kentucky.
- Anderson JW, Johnson BM, Cook-Newell; Meta-analysis of the effects of soy protein on serum lipids. New ENgl J Med 1995; 333(5): 276-282.
- Markus CR, Oliver B, deHaan EH; Whey Protein. Am J Clin Nutri 2002: 75: 1051-56.