Supplement manufacturers have done a wonderful job of confusing the fitness wanting public. For the last 5 years the bodybuilding community has gobbled up whey protein.
Research proved that quick stomach emptying by many of the amino acids consumed via whey protein are burned up with enzymes. Soy manufacturers decided to increase the number of protein grams in a serving because even more protein would have to be consumed, and more protein was sold.
Soy was popular with vegetarians. The Soy manufacturers watched as whey protein sales sky rocketed, and, in to get their own piece of the pie, they went after the “health” market, primarily women. Many of the research studies the soy manufacturers cite are valid, but do not represent the whole picture.
In one particular study published in France, two groups of apparently healthy men were fed isocaloric diets with one group using soy protein, the other using animal products as a protein source. The goal was to see if there was a reduced propensity for gallstones if animal proteins are replaced by soy. Since gallstone accumulation can be linked with crystallization of cholesterol, at its conclusion the study examined cholesterol levels.
Cholesterol crystallization was found to be slowed in the soy consuming group. This led to the idea that soy will aid in the prevention of gallstones. Unfortunately, the study failed to address an important point. There was zero control of vegetable intake. Soy is a vegetable and is very high in isoflavones.
Isoflavones are very closely tied to many health benefits including a lowering of cholesterol levels. On the other hand, we’ve known for some time that the consumption of meat is linked with an elevation of the cholesterol level. This does not mean that people who eat soy will have better cholesterol than people who eat chicken, turkey, egg, fish, and other vegetables. This clearly shows that conclusions drawn from studies are very often taken out of their proper context and overemphasized.
Scientific studies indicate that there are cancer fighting benefits of a meal plan rich in vegetables like soy. Most people would not assume that people who ingest soy instead of milk, egg-whites, and lean protein will demonstrate improved health, if a exercise ingredient is included, the study would be invalidated.
Much of the information promoted specific to soy is published by companies with a vested interest in Soy product sales, like The USB (United Soybean Board). This doesn’t mean that soy isn’t an excellent source of protein, rather it shows that the health benefits have been taken out of context to sell Soy products.
As far as metabolism is concerned it appears that you are best off ingesting supplemental protein from a mix of whey & casein protein. The new protein supplements will hit the market and feature this exact combination of proteins. You are best to include a wide a variety of food as possible in your nutrition program.
