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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.

  1. Whitney E, Rolfes RR. Understanding Nutrition, 11th ed. Belmont, CA: Thompson Learning; 2008.
  2. Whey Protein monograph. Natural Medicines Comprehensive Database. Retrieved February 24, 2009 from
  3. Baruchel S, Olivier R, Wainberg M. Anti-HIV and anti-apoptotic activity of the whey protein concentrate: IMMUNOCAL. Int Conf AIDS 1994;10:32 (abstract # 421A).
  4. Whey Protein monograph. Natural Medicines Comprehensive Database. Retrieved February 24, 2009 from
  5. Cribb PJ, Wiliams AD, Carey MF, Hayes A. The effect of whey isolate and resistance training on strength, body composition, and plasma glutamine. Int J Sport Nutr Exerc Metab 2006;16:494–509.
  6. Whey Protein monograph. Natural Medicines Comprehensive Database. Retrieved February 24, 2009 from
  7. Whey Protein monograph. Natural Medicines Comprehensive Database. Retrieved February 24, 2009 from
  8. Bounous G, Batist G, Gold P. Whey proteins in cancer prevention. Cancer Lett 1991;7:91–4.
  9. Hakkak R, Korourian S, Shelnutt SR, et al. Diets containing whey proteins or soy protein isolate protect against 7,12-dimethylbenz(a) anthracene-induced mammary tumors in female rats. Cancer Epidemiol Biomarkers Prev 2000;9:113–7.
  10. McIntosh GH. Colon cancer: dietary modifications required for a balanced protective diet. Prev Med 1993;22:767–74.
  11. Papenburg R, Bounous G, Fleiszer D, Gold P. Dietary milk proteins inhibit the development of dimethylhydrazine-induced malignancy. Tumor Biol 1990;11:129–36.
  12. Whey Protein monograph. Natural Medicines Comprehensive Database. Retrieved February 24, 2009 from
  13. Farnfield MM, Trenerry C, Carey KA, Cameron-Smith D. Plasma amino acid response after ingestion of different whey protein fractions. Int J Food Sci Nutr. 2009 Sep;60(6):476–86.
  14. U.S. Dairy Export Council. Protein. Retrieved January 30, 2013from Item Number=82510.
  15. Cribb PJ, Wiliams AD, Carey MF, Hayes A. The effect of whey isolate and resistance training on strength, body composition, and plasma glutamine. Int J Sport Nutr Exerc Metab 2006;16:494-509.
  16. Cribb PJ, Williams AD, Stathis CG, et al. Effects of whey isolate, creatine, and resistance training on muscle hypertrophy. Med Sci Sports Exerc 2007;39:298–307.
  17. Candow DG, Burke NC, Smith-Palmer T, Burke DG. Effect of whey and soy protein supplementation combined with resistance training in young adults. Int J Sport Nutr Exerc Metab 2006;16:233-44.
  18. Cribb PJ, Williams AD, Carey MF, Hayes A. The effect of whey isolate and resistance training on strength, body composition, and plasma glutamine. Int J Sport Nutr Exerc Metab 2006;16(5):494-509.
  19. Cribb PJ, Wiliams AD, Carey MF, Hayes A. The effect of whey isolate and resistance training on strength, body composition, and plasma glutamine. Int J Sport Nutr Exerc Metab 2006;16:494-509.
  20. Hayes A, Cribb PJ. Effect of whey protein isolate on strength, body composition and muscle hypertrophy during resistance training. Curr Opin Clin Nutr Metab Care 2008;11(1):40-4.
  21. Tang JE, Manolakos JJ, Kujbida GW, et al. Minimal whey protein with carbohydrate stimulates muscle protein synthesis following resistance exercise in trained young men. Appl Physiol Nutr Metab 2007;32:1132-8.
  22. Power O, Hallihan A, Jakeman P. Human insulinotropic response to oral ingestion of native and hydrolysed whey protein. Amino Acids 2008 Aug 5. [Epub ahead of print].
  23. Royle PJ, McIntosh GH, Clifton PM. Whey protein isolate and glycomacropeptide decrease weight gain and alter body composition in male Wistar rats. Br J Nutr 2008 Jul;100(1):88-93.
  24. Keogh JB, Clifton P. The effect of meal replacements high in glycomacropeptide on weight loss and markers of cardiovascular disease risk. Am J Clin Nutr 2008;87(6):1602–5.
  25. Burton-Freeman BM. Glycomacropeptide (GMP) is not critical to whey-induced satiety, but may have a unique role in energy intake regulation through cholecystokinin (CCK). Physiol Behav 2008;93(1-2):379–87.
  26. Zavorsky GS, Kubow S, Grey V, Riverin V, Lands LC. An open-label dose-response study of lymphocyte glutathione levels in healthy men and women receiving pressurized whey protein isolate supplements. Int J Food Sci Nutr 2007;58(6):429–36.
  27. Tsai WY, Chang WH, Chen CH, Lu FJ. Enchancing effect of patented whey protein isolate (Immunocal) on cytotoxicity of an anticancer drug. Nutr Cancer 2000;38(2):200–8.
  28. Dietary Reference Intakes for Energy, Carbohydrate. Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids (2002/2005). National Academy of Sciences. Institute of Medicine. Food and Nutrition Board. This report may be accessed via
  29. National Collaborating Centre for Women’s and Children’s Health (UK). Antenatal Care: Routine Care for the Healthy Pregnant Woman. NICE Clinical Guidelines, No. 62. London: RCOG Press; March 2008:108–109.
  30. Custódio Afonso Rocha V, Ramos de Arvelos L, Pereira Felix G, et al. Evolution of nutritional, hematologic and biochemical changes in obese women during 8 weeks after Roux-en-Y gastric bypasss. Nutr Hosp. 2012 Aug;27(4):1134–40.
  31. Faria SL, Faria OP, Buffington C, de Almeida Cardeal M, Ito MK. Dietary protein intake and bariatric surgery patients: a review. Obes Surg. 2011 Nov;21(11):1798-805.
  32. Moizé V, Andreu A, Rodríguez L, et al. Protein intake and lean tissue mass retention following bariatric surgery. Clin Nutr. 2012 Nov 14. pii: S0261-5614(12)00239–7.
  33. Andreu A, Moizé V, Rodríguez L, Flores L, Vidal J. Protein intake, body composition, and protein status following bariatric surgery. Obes Surg. 2010 Nov;20(11):1509–15.
  34. Encinosa WE, Bernard DM, Chen CC, Steiner CA. Healthcare utilization and outcomes after bariatric surgery. Med Care. 2006 Aug;44(8):706–12.
  35. Dubois L, Farmer AP, Girard M, Peterson K. Preschool children’s eating behaviours are related to dietary adequacy and body weight. Eur J Clin Nutr. 2007 Jul;61(7):846–55.
  36. Sources of Protein among US Children & Adolescents, 2005–06. Risk Factor Monitoring and Methods Branch Web site. Applied Research Program. National Cancer Institute. Updated December 21, 2010. Accessed December 10, 2012 from http://riskfactor.cancer. gov/diet/foodsources/protein/.
  37. Fulgoni VL 3rd. Current protein intake in America: analysis of the National Health and Nutrition Examination Survey, 2003-2004. Am J Clin Nutr. 2008 May;87(5):1554S–7S.
  38. Wolfe RR. The role of dietary protein in optimizing muscle mass, function and health outcomes in older individuals. Br J Nutr. 2012 Aug;108 Suppl 2:S88–93.
  39. Fulgoni VL 3rd. Current protein intake in America: analysis of the National Health and Nutrition Examination Survey, 2003-2004. Am J Clin Nutr. 2008 May;87(5):1554S–7S.

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.