Out of the many protein sources out there, whey protein is the ultimate. It comes from milk. During the process of turning milk into cheese, whey protein is separated out. Protein can be found in a variety of foods - mainly meats, such as fish, beef, and chicken.

Dairy products as well as eggs, cottage cheese, soy and vegetable protein also contain good amounts of protein. Nevertheless, none of these sources compares in quality or ease of use like whey protein. Whey protein has the highest value in providing branched-chain amino acids, which result in building and retaining muscle tissue.

What does it do and what scientific studies give evidence to support this?

Whey protein (the highest quality and best form of protein) is incredible stuff. It provides the body with the necessary building blocks to produce amino acids that are used for building muscle tissue. Whoa! Nearly every bodybuilder knows the importance of protein supplementation. Studies have been conducted that compare whey protein to other sources. They have found that whey protein contains the perfect combination of overall amino acid makeup... and in just the right concentrations for optimal performance in the body. Both hormonal and cellular responses seem to be greatly enhanced with supplementation of whey protein, too! Not to mention the benefits whey protein has on the body's immune system according to documented scientific research. Whey protein also plays a role as an antioxidant and helps support a health immune system. Most importantly, consistent whey protein intake coupled with exercise will result in consistent muscle building.

Who needs it and what are some symptoms of deficiency?

Whey protein is very, very important for bodybuilders, dieters, and shoot, just about everybody! Since athletes and bodybuilders work out often, protein levels become depleted. By being a direct precursor to building muscle and essential amino acids, such as glutamine (a muscle enhancer, endurance builder, and muscle deterioration reducer), the content from high quality whey protein not only can, but will help one's muscles recover and grow faster by bring up the levels of protein. With dieting and those wishing to lose some extra fat, whey protein can be very useful because a good intake of protein balances blood sugar levels, while carbohydrates cause blood sugar levels to fluctuate. When the blood sugar levels stay balanced, one is not as prone to rampant eating and has more energy and greater fat loss. Whey protein allows a person to control his or her diet effectively. Most people who want to change their body for the better could benefit from whey protein supplementation; however, since protein is naturally found in many food items deficiency is usually not a problem.

How much should be taken? Are there any side effects?

Training athletes often consume 25 grams of whey protein per day. Bodybuilders who want serious gains (and are burning serious calories), generally consume 150 grams per day. Extremely high doses of whey protein is not recommended, as this will cause the body's liver to be overloaded and you won't get the same benefits as with a consistent lower amount taken three to five times per day.

Whey protein has long been considered the "Gold Standard" of protein for serious athletes who work hard to develop and sustain a lean, strong and well-defined physique. Research studies support this belief. Athletes need more protein in their diet, often as much as twice the recommended daily allowance. The protein they choose makes a difference and here are several reasons why whey protein is a preferred choice for athletes of all types.

- Whey protein is a naturally complete protein, meaning that it contains all of the essential amino acids required in the daily diet. It has the ideal combination of amino acids to help improve body composition and enhance athletic performance.

- Whey protein is a rich source of branched chain amino acids (BCAAs), containing the highest known levels of any natural food source. BCAAs are important for athletes since unlike the other essential amino acids, they are metabolized directly into muscle tissue and are the first ones used during periods of exercise and resistance training. Whey protein provides the body with BCAAs to replenish depleted levels and start repairing and rebuilding lean muscle tissue.

- Whey protein is an excellent source of the essential amino acid, leucine. Leucine is important for athletes as it plays a key role in promoting muscle protein synthesis and muscle growth. Research has shown that individuals who exercise benefit from diets high in leucine and have more lean muscle tissue and less body fat compared to individuals whose diet contains lower levels of leucine. Whey protein isolate has approximately 50% more leucine than soy protein isolate.

- Whey protein is a soluble, easy to digest protein and is efficiently absorbed into the body. It is often referred to as a "fast" protein for its ability to quickly provide nourishment to muscles.

- Whey protein helps athletes maintain a healthy immune system by increasing the levels of glutathione in the body. Glutathione is an anti-oxidant required for a healthy immune system and exercise and resistance training may reduce glutathione levels. Whey protein helps keep athletes healthy and strong to perform their best.