Soy and Whey manufacturers did a superb job of confusing the public. For 5 years now the fitness and health community has been drinking up whey.
Eventually a research studies showed that due to its quick stomach emptying properties most of the protein consumed via whey protein is metabolized (burned up by liver enzymes). The whey manufacturers first responded by increasing the number of grams per serving. More protein would have to be consumed, thus more protein was sold.
Soy is popular with vegetarians. The Soy manufacturers looked on 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.
One study looked at two groups of healthy middle aged men that were given isocaloric meals with one group eating soy protein, while the other consumed animal protein. They wanted to find out if there is a decreased propensity of gallstones when animal products are replaced by soy proteins. Very often gallstone accumulation is linked to cholesterol crystallization, so they then examined the participants cholesterol levels.
The study showed that cholesterol crystallization was slightly retarded in the soy group extrapolating that soy can aid in preventing gallstones. Here’s what the study neglected to address. There wasn’t any control over fruit and vegetable intake. Soy is a vegetable, and it does happen to fall into the group of veggies that are high in isoflavones.
Isoflavones have been closely linked to health benefits including a lowering of cholesterol. We’ve known for years that a predominance of animal meats can have adverse affects on cholesterol, but that doesn’t mean that someone consuming soy would have better cholesterol levels than someone eating combinations of chicken breast, turkey breast, fish, and egg whites and a variety of natural vegetables. You can see how the conclusions drawn from studies can be misconstrued and over-emphasized in significance.
While a great number of scientific studies can be held up to show the cancer resistive benefits of a diet rich in vegetable foods (soy included), we can not extrapolate from those studies that someone consuming soy instead of milk proteins, egg proteins, and lean animal proteins will exhibit better health, and if an exercise component is included, the conclusions in non-exercising individuals are almost invalidated.
Most of the research promoted about soy is publicized by companies with a financial stake in Soy Protein sales. The Soybean Board is a good example. Very often the elements of a sound study are taken out of context to boost sales of soy.
From a metabolic benefit standpoint, it appears based on the most recent and applicable studies, that you are best off getting your supplemental protein from a mix of whey and casein. Watch as the newest protein supplements to hit the market feature this mix. Unless you are vegetarian, I’d suggest you’re best off including as wide a variety of foods as possible in your complete dietary regimen. If this includes a daily soy protein supplement I believe you’ll do quite well.
