What is whey protein? Find out if this supplement is good for you

Few industries are doing as well as the dietary supplement industry. The global size of the market reached 71.81 billion in 2021 and is expected to grow by another 10 million to a whopping 128.64 billion by 2028.

While supplemental nutrients such as vitamin D, vitamin C, vitamin B12, magnesium, and calcium are the most commonly consumed, many others, including ginseng, coconut oil, ashwagandha, and creatine, have also grown significantly in popularity over the past decade. There is no denying that interest in these products is high. But among these dietary supplements, few are advertised as frequently and as heavily as whey protein.

What is whey protein?

Whey protein is a popular protein supplement that can improve athletic performance and build stronger, leaner muscles. It’s typically taken before or after a workout and consumed as a powder (often diluted in a smoothie or cup of water/milk) and also sold as part of a ready-to-drink protein shake.

The protein comes from whey – the watery part of milk that is separated from the curds during cheese making. “Cow’s milk is made up primarily of two proteins: casein and whey,” says Uma Naidoo, MD, director of nutritional and lifestyle psychiatry at Massachusetts General Hospital and author of “This is Your Brain on Food.” She explains that the whey portion of the protein is considered “a complete protein because it contains all nine essential amino acids.”

The nine amino acids are histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine. According to the National Institute of Health’s National Library of Medicine, these amino acids perform vital bodily functions, including nutrient absorption and tissue repair, and must be obtained through a healthy diet or supplementation.

Carol Johnston, PhD, RD, Professor of Nutrition at Arizona State University, says that consuming whey protein is one way to “increase dietary protein intake” and that whey protein’s “amino acid profile allows for maximal protein synthesis.”

What effect does whey protein have on the body?

Whey protein is marketed with several health benefits, but research demonstrating the full extent of each benefit (or lack thereof) is ongoing. “A literature review found that whey protein supplementation supports athletic performance,” explains Naidoo.

Whey protein is also touted as helping with diabetes, immune health, asthma and weight loss, although solid science has yet to back up such claims. At a minimum, “whey protein is a highly bioavailable source of animal protein that is rapidly absorbed after ingestion,” says Johnston. And protein has been shown to promote muscle growth and development, strengthen bones, and aid in cell growth and repair.

Is Whey Protein Safe to Take?

Despite some whey protein health benefits, it is classified as a dietary supplement, which means it is only regulated by its manufacturers and is not tested for safety or effectiveness by the U.S. Food and Drug Administration (FDA) like foods and drugs. In fact, Harvard Medical School warns of some “hidden dangers” in protein powders, including high levels of sugar and calories, the presence of unknown substances, and even toxins that have been discovered in some protein powder brands.

However, whey protein is not known to be harmful in most adults when taken in moderate amounts, particularly those with protein deficiency or protein requirements such as athletes, the elderly, or vegetarians. Naidoo says that for some of these people, whey protein is a “considerable option to supplement protein intake,” but adds that such supplementation should only be temporary (unless directed by a doctor) and should not replace a healthy diet. “A systematic review of both experimental and randomized research studies examined whey protein and its effects on physical health and showed that continued long-term use without the help of a doctor or nutritionist can cause kidney and liver side effects,” she said.

In other words, the best and safest way to ensure you’re getting enough protein is to get it from natural sources, as many people do in their daily diet. “People who eat a healthy diet, including all food groups, are likely consuming adequate amounts of protein,” says Johnston.

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