Milk is made up of two proteins: casein and whey. Whey protein can be separated from casein either directly in milk or be formed as a by-product of cheese production. Whey protein is considered a complete protein because it contains all 9 essential amino acids. It has a low lactose content. There are many benefits associated with consuming whey protein, and researchers are continually discovering new potential therapeutic properties. Here, we explain the possible benefits and examine some of the side effects and potential risks. Quick facts about whey protein: Many of the potential benefits are based on individual studies, and more evidence is needed before a definitive conclusion can be made. Whey protein is a mixture of beta-lactoglobulin, alpha-lactalbumin, bovine serum albumin, and immunoglobulins. Possible benefits include weight loss and reduction of cholesterol. Possible risks include nausea and headaches, but at mild doses, whey protein is not considered dangerous. Benefits Improved weight loss In a study of 158 individuals, published in the journal Nutrition & Metabolism, those who consumed whey protein “lost significantly more body fat and showed greater preservation of lean muscle compared with individuals who consumed the control beverage.” Anti-cancer properties Promising results were published in the journal Anticancer Research regarding the use of whey protein concentrate in cancer treatment. More research is required. Cholesterol reduction A study published in The British Journal of Nutrition provided whey supplements to 70 overweight men and women for 12 weeks and measured various parameters such as lipid and insulin levels. They found that “there was a significant reduction in total cholesterol and LDL cholesterol at week 12 in the whey group compared with the casein (group).” Asthma Whey protein may improve immune response in children with asthma. A small study involving 11 children, published in the International Journal of Food Science and Nutrition, found that children with asthma who were given a supplement of 10 grams of whey protein twice a day for one month had an improved immune response. Reduction of weight loss in people with HIV A study published in the journal Clinical and Investigative Medicine found that whey protein may help reduce weight loss among HIV-positive patients. Potential risks Some people who are allergic to milk may also be specifically allergic to whey. At mild doses, whey protein usually does not cause adverse effects. However, consuming very high doses may cause: stomach pain cramps reduced appetite nausea headache fatigue Consistently high doses of whey protein may also cause acne. From a nutritional perspective, whey protein is quite unusual and has no natural equivalent. Some people believe there are risks associated with highly processed dietary foods like these, because although they contain many nutrients, the balance is heavily shifted toward protein. Types There are three main types of whey protein: whey protein concentrate (WPC), whey protein isolate (WPI), and hydrolyzed whey protein (WPH). Let’s look at them in order: Whey Protein Concentrate (WPC) – WPC contains low levels of fat and carbohydrates. The protein percentage in WPC depends on how concentrated it is. Lower-end concentrates tend to have around 30% protein, while higher-end products can reach up to 90%. Whey Protein Isolate (WPI) – WPI is further processed to remove all fat and lactose. WPI is usually at least 90% protein. Hydrolyzed Whey Protein (WPH) – WPH is considered the “pre-digested” form of whey protein, as it has already undergone partial hydrolysis—a process necessary for the body to absorb protein. WPH does not require as much digestion as the other two forms. WPH is also commonly used in medical protein supplements and infant formulas due to its improved digestibility and reduced allergenic potential. Muscle Building and Weight Loss Supplementing with whey protein along with resistance training can help improve muscle protein synthesis and promote the growth of lean body mass. A study published in the International Journal of Sports Nutrition and Exercise Metabolism concluded that “whey protein supplementation during resistance training provides some benefit compared to resistance training alone.” Additionally, “men who supplemented with whey protein had greater relative gains in lean body mass.” Much greater strength gains are associated with whey protein isolate supplementation compared to casein. This was demonstrated in another study published in the International Journal of Sports Nutrition and Exercise Metabolism, which concluded that “in two groups of matched, resistance-trained males, whey protein isolate provided significantly greater gains in strength, lean body mass, and reductions in fat mass compared with casein supplementation during a 10-week intense resistance training program.”