Whey Vs. Soy Shakes

Proteins contain amino acids, which are the basic building blocks of muscle and necessary to give your body long-term energy sources. You should try to consume between 46 and 56 g of protein per day -- a number that may depend on your weight and physical activity level. If you have difficulty fitting enough protein into your daily diet or need a faster protein source, protein shakes are a possible solution. However, there are different protein source options for blending, including whey and soy protein.

Sources

Soy protein is made from the soybean plant. Soybeans are naturally high in protein. Soy protein also can help lower cholesterol levels. Whey protein is derived from milk and is the byproduct of making cheese. Whey protein breaks down to two protein types: casein, which is the largest portion of cow's milk, and whey protein, which represents 20 percent of cow's milk. Whey and soy proteins are sold as isolates, which are a purer protein form, and concentrate, in which the protein form is not as significant.

Bone Density

Soy protein shakes have been linked with reducing osteoporosis risk in women who have gone through menopause. While the effect of soy on bone density may be small, whey protein is believed to have less effect on bone density and reducing osteoporosis risk in women.

Maintaining Muscle Mass

Protein shakes are best after a resistance-training workout because they help your body rebuild muscle. Whey protein is associated with helping maintain muscle mass slightly more efficiently than soy protein. This is important because you can lose muscle mass if you are trying to lose weight. Losing lean muscle mass can affect your metabolism because muscle burns more calories than fat when you are at rest. If you are trying to lose weight or maintain your lean muscle, whey protein may be the better option.

Quality

Proteins are rated on five chief factors: digestibility, number of amino acids, how efficiently the protein is consumed, how much nitrogen is retained and how much nitrogen is used. Both whey and soy protein are rated as 100 percent digestible. Whey protein contains more amino acids than soy protein concentrate and is used slightly more efficiently by the body.

Taste

In the absence of flavoring added to either powder, whey protein has a more neutral taste than soy protein. Soy protein can have a slight nutty flavor when blended into shakes. For this reason, protein flavor may come down to personal preference.