Protein supplements are commonly used by people as part of a fitness program, and indeed there is good reason to do so. In fact, protein is one of the most important substances for the maintenance of good health and vitality. It is of primary importance in the growth and development of all body tissues including muscles, blood, skin, hair, nails and internal organs. Protein is also needed for the formation of hormones, enzymes and antibodies. In addition to being the major source of building materials for the body, protein may be used as a source of heat and energy. Each gram of protein provides four calories. This energy function of protein is spared when sufficient fats and carbohydrates are present in the diet.1 While any protein source can serve these functions, whey protein provides distinct advantages as a source of supplemental protein.

Whey, a by-product of cheese manufacturing, contains proteins. These include alpha-lactalbumin, beta-lactoglobulin, lactoferrin, serum albumin, lysozyme, and immunoglobulins A, G, and M2 and relatively large amounts of the amino acid cysteine.3 Whey also contains carbohydrates, primarily lactose, and the minerals calcium, sodium, phosphorus, and potassium.4

Whey protein is derived from whey and tends to provide a higher concentration of essential amino acids than other protein sources.5 Also, whey protein typically contains 24 percent branched chain amino acids, which are readily oxidized as an energy source during stress. In addition, whey protein is also a source of cysteine, a precursor to the vital intracellular antioxidant glutathione (GSH),6 which is depleted by oxidative stress, which occurs during exercise, infections, trauma, or major surgery.7 In fact, some researchers think that whey protein may help play a role in cancer prevention by providing GSH precursors and increasing levels of GSH in the tissues.8 This is consistent with animal research showing that protein from whey may protect against certain cancers.9,10,11

Whey protein varies in the immunoglobulins and other proteins present, depending on the processing method used to produce the final form of whey protein.12 These forms include whey protein isolate, whey protein concentrate, and hydrolyzed whey protein. This article will focus on whey protein isolate.

Arguably, the best way to process whey protein isolate (WPI) is via cross-flow ultrafiltration. This process preserves protein microfractions and separates the protein from whey without the use of heat or damaging chemicals. As a result WPI is virtually fat and lactose free, is extremely digestible, and has a good taste. WPI does not tend to cause gas, bloating or other gastrointestinal distress.13 Furthermore whey protein isolate is easily digested and absorbed, and has received the highest score (1.14) of any protein tested according to the Protein Digestibility Corrected Amino Acid Score (PDCAAS), the preferred method for evaluating protein quality.14

Clinical research shows that taking 1.2–1.5 grams WPI per kilogram of body weight, per day in combination with strength training for 6–10 weeks increased lean body mass, strength, and muscle hypertrophy compared to placebo. 15,16,17 In one double-blind study,18 recreational bodybuilders supplemented their normal diet with WPI (1.5 grams per kilogram of body weight, per day) or another protein for 10 weeks. The results were that the WPI group experienced a significant gain in lean mass compared to the other protein group (11 lbs versus 1.76 lbs) and a significant reduction in fat mass compared to the other protein group (-3.3 lbs versus +0.44 lbs). The bodybuilders also achieved significant improvements in strength.

WPI supplementation also results in higher blood amino acid concentrations compared to some other protein sources. This results in greater stimulation of protein synthesis,19 thus providing the foundations for preservation and production of muscle mass. Several studies involving supplementation with whey protein have been shown to be effective in augmenting the effects of resistance exercise, particularly when supplementation occurs in the hours surrounding the exercise training.20 Research in healthy volunteers showed that consuming 10 grams WPI following exercise can stimulate muscle protein synthesis, which could potentially lead to increased muscle hypertrophy.21 Research also shows that men who ingest 45 grams of WPI had significantly increased levels of insulin. In research, WPI increased insulin secretion to a greater extent than HWP.22

WPI AND FAT LOSS WPI and one of its components, glycomacropeptide (GMP), were fed to a group of rats, while other rats received a standard diet. The results were that body-weight gain was 21 percent lower on the WPI diet. GMP has an effect of reducing fat mass and insulin levels.23 A meal replacement drink containing 15 grams of WPI enriched with GMP (GMP-WPI) was given to 72 participants, twice daily for 12 months. The results were that the participants lost fat weight, and decreased total and LDL cholesterol, triglycerides, glucose, insulin, and blood pressure.24 One reason that WPI may be effective for fat loss is that it is better at creating a sense of fullness than other types of protein types. In research, feelings of fullness were greater after consuming WPI.25

Thirty-one healthy subjects given WPI produced increased levels of GSH. Those who ingested 45 grams daily of WPI had the highest increase in GSH, 24 percent.26 This increase in GSH may be part of the reason that, in other research, WPI enhanced the ability of a chemotherapy drug to destroy cancer cells.27

While everyone needs protein, there are specific population groups that could benefit by supplemental protein. In addition to athletes/bodybuilders (as previously discussed), this includes pregnant women, those who have undergone bariatric surgery, young children who are picky eaters, some adolescent girls and older adults.

The protein RDA for women is 46 grams per day. The protein RDA for pregnant women is 71 grams per day. That’s 25 grams more per day than non-pregnant women.28 Since pregnancy is often associated with indigestion and heartburn, 29 it may make sense to supplement protein intake with an easily digested protein such as WPI.

Individuals who have undergone bariatric surgery often experience a reduction in protein intake.30,31 This is problematic since increasing protein intake to at least 60 grams per day is recommended to help those who have undergone bariatric surgery retain more lean mass (i.e., Muscle).32,33 Given that bariatric surgery may be associated with digestion and absorption issues (i.e., gastric dumping syndrome),34 the use of an easily digested protein such as WPI makes sense for supplementing protein intake.

Research35 has shown that children who are picky eaters are more likely to consume less than the recommended amounts of protein (i.e., meat and alternatives) as well as fruit and vegetables. Furthermore, research36 has also shown that some top sources of protein for children include pizza, beef and burgers, which often contribute substantial saturated fat. WPI is a healthy, low-fat option for supplementing protein intake in children.

According to the National Health and Nutrition Examination Survey,37 7.7 percent of adolescent females consume protein levels below their estimated average requirement.

While the reasons for this are not clear, protein supplementation may have value


Muscle mass and function is progressively lost with aging, so that by the age of 60 many individuals have reached a threshold where function begins to be affected. Increasing protein intake may help. Dietary protein intake helps stimulates muscle protein synthesis and may lead to improved muscle mass, strength and function over time, which in turn may help improve health outcomes in older individuals. Some researchers suggest that the optimal protein intake for an older individual is greater than the RDA.38 Since protein intake tends to decline with age, especially among 7.2–8.6 percent of older women consuming protein levels below their estimated average requirement,39 this suggestion has merit.

Protein is important for multiple functions in the body, not the least the repair growth of muscles. As a supplemental source, whey protein offers several advantages and has significant research to support its use.

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Gene Bruno, MS, MHS

Gene Bruno is the Dean of Academics and Professor of Dietary Supplement Science for Huntington College of Health Sciences (a nationally accredited distance learning college offering diplomas and degrees in nutrition and other health science related subjects. Gene has two undergraduate Diplomas in Nutrition, a Bachelor’s in Nutrition, a Master’s in Nutrition, a Graduate Diploma in Herbal Medicine, and a Master’s in Herbal Medicine. As a 32 year veteran of the Dietary Supplement industry, Gene has educated and trained natural product retailers and health care professionals, has researched and formulated natural products for dozens of dietary supplement companies, and has written articles on nutrition, herbal medicine, nutraceuticals and integrative health issues for trade, consumer magazines, and peer-reviewed publications. Gene's latest book, A Guide to Complimentary Treatments for Diabetes, is available on, and other fine retailers.