Ingredients In Protein Supplements

Nutritional supplements are a multi-million dollar business, with protein supplements being a major factor in the profit structure of the industry. Whether you use a personal trainer for exercise program design, or just read a lot of fitness magazines, you've likely had recommendations to use these supplements. What exactly are the ingredients that you'd be putting into your body though? How do they work and which would be most beneficial to you?

Whey Protein

The most common source of protein for supplements is whey. Whey protein contains low levels of fat and cholesterol and high levels of pure protein. Whey isolate powders can be as much as 90 percent protein by dry weight measure.
Choose whey protein if your primary goal is muscle synthesis. Use whey protein at breakfast and in post-workout supplements in order to increase the level of amino acids in your bloodstream and muscles. The amino acids in whey protein are easily digested and then transported to the muscles to be re-synthesized as muscle cellular protein.

Casein Protein

Casein is the second most common source of supplement protein after whey. It is composed of the solids suspended in liquid milk and accounts for 80 percent of the total protein value of milk. Because casein is insoluble in water, it tends to clot in the stomach, slowing digestion. This slowing of the digestive process allows the protein to be released over a longer period of time. This leads to a higher level of serum protein over a longer period of time.
Choose casein protein for a pre-bedtime supplement in order to minimize muscle catabolism during the sleep fasting period. Combine casein protein with a fiber-rich complex carbohydrate to slow digestion further, allowing the introduction of anabolic proteins and amino acids into the body over a longer duration while sleeping.

Soy Protein

Soy protein is used in a variety of foods, from the obvious like tofu and imitation meat products (Textured Vegetable Protein, or "TVP") to the less obvious breakfast cereals and salad dressings.
Derived from the soybean, the protein content of soy supplements can range from 60 to 90 percent of dry matter weight. Because it is a "complete protein" derived from non-animal sources, soy is often the protein supplement of choice for vegans and other vegetarian dieters.
For men that may be a poor choice though. Mark Rippetoe, in his book "Practical Programming for Strength Training," cites a National Institute of Health study by S. Goodwin et al, that points out the high levels of estrogenic compounds in soy protein. The study found that 56 g of soy protein per day reduced serum testosterone levels in healthy adult males between four and 19 percent in just four weeks.
Avoid soy protein supplements if you want to increase muscle size and strength. The reduction in testosterone can lead to poor muscle production since it is the hormone responsible for muscle production in the body.