Whey protein has been considered the higher quality protein source for quite a while, but that's not necessarily true anymore. New studies suggest that both are on the same level, yet they're not altogether equal.

Soy protein comes from soybeans, hence the name. And being that it is a plant protein it has always been considered substandard. The recent studies have shown that soy protein has a significant effect on testosterone and muscle building.

Soy protein powder concentrates were introduced about twenty years ago as a food supplement. But it was high in sodium and carbohydrates with a low amino acid composition, making it a low quality muscle builder.

There are some nutritional experts who believe that soy produces low energy levels, poor digestion, infertility, and hypothyroidism. On the other hand, there are those who believe soy to be harmless and even beneficial.

Soy protein has come a long way since they learned how to extract the protein from the bean then condense it. This is called soy protein isolate with ninety percent protein and no carbs or fats. Soy protein is the only plant protein with high-quality, which has all of the necessary amino acids needed for growth and evolution. Soybeans, endemic to Asia, came to America around 1879 and were used primarily in animal products.

Soy-protein isolate, whey, egg white, and casein proteins have been deemed the highest quality proteins and actually compliment each other. Soy protein is available in three different forms.

Texture soy protein comes from soy protein concentrates, which is found in foods such as imitation pork, chicken and burgers. Soy protein concentrate, basically, is what's left after extracting the fat. Soy protein isolate is the highest quality soy available. Composed of mostly de-fatted beans, soy protein isolate is the purest protein source.

Soy far exceeds whey in its glutamine content, which is particularly interesting to the bodybuilder. Soy Isolates' high concentration of glutamine, amino acids and arginine are essential to the immune system, and the release of growth hormones.

Soy protein was once thought to raise estrogen and decrease testosterone, but the latest study disproves that theory. The study suggests that soy is a practical workout beverage. Furthermore, it was stated that a daily supplement of a soy and whey combination produced lean body mass with no effect on estrogen or testosterone levels.

Soy has been proven to lower triglyceride levels, LDL (bad) cholesterol, and improve kidney function. Soy proteins are also easier on the kidneys.

Therefore, soy is the better protein and when used in combination with whey, it can pack a powerful punch.

Source: http://www.associatedcontent.com/article/855977/whey_protein_verses_soy_...