3 Major Differences Between Whey and Soy Protein


Supplementing your diet with a healthful source of protein has been shown to be beneficial to skeletal and muscular health, especially after exercising. During an intense workout, the body excretes electrolytes and burns the most readily available protein to use as energy. Supplementing with a soy or whey based protein drink is a popular method of consuming more protein. There are major differences between these 2 protein sources of which consumers should be mindful.

Possible Hormonal Influences of Soy

Unlike whey, which is derived from cow’s milk, soy protein is derived directly from the humble soybean. However, soy has been shown to contain substances, called isoflavones, that may mimic the hormonal action of estrogen. It is thought that isoflavones may lower testosterone levels. Increases in estrogen levels may cause:

  • Thyroid issues
  • Low energy
  • Digestive troubles
  • Fertility issues

However, there are many studies that oppose this viewpoint, claiming that the influence of soy upon human estrogen levels is rather innocuous. Therefore, most people can consume soy products without any trouble, but this is one issue of which consumers should be aware.

The Issue of Lactose

Whey is the watery portion of milk that separates from curds during the process of cheese making. Whey is a complete protein and an excellent source of amino acids. Due to its chemical makeup, it has a high degree of bio-availability. This means that the human body can quickly digest and absorb the nutrient profile of whey, making it a great choice after an intense workout for quick refueling.

However, since whey is a dairy product, it is not suitable for people who suffer from a dairy allergy or who are lactose intolerant. People who are vegan also would want to avoid this source of protein, but they can count on soy to provide a complete protein profile. While it may not be as readily digested by the body, soy is still a good protein choice for individuals who need to avoid dairy in their diet.

Weight Loss & Muscle Building

Although soy is a complete source of protein, a 2013 government study found that people who supplement with whey protein build more lean muscle mass and lose weight more effectively than those who choose soy. Although the mechanism by which whey works differently from soy is as of yet unknown, the results draw a clear conclusion that whey is a superior source of fitness nutrition.

Although whey may yield more weight loss benefits, soy is still a healthful and effective fuel for the human body. Despite their differences, both soy and whey can be part of a healthful lifestyle.

Betty Abernathy

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