Protein: Unleashing the Power of Whey Protein

Introduction

Protein is a fundamental component of our bodies, playing a crucial role in the growth and repair of tissues, the production of hormones and enzymes, and the maintenance of overall health. While all proteins are not created equal, some stand out for their exceptional benefits. One such protein is whey protein, which contains a remarkable range of essential amino acids that are rapidly absorbed by the body. Numerous studies have shown that whey protein can significantly increase strength, promote muscle growth, and aid in substantial weight loss (1, 2Trusted Source). However, whey protein is not just about protein content. It is also packed with various other nutrients, each with its own potent biological effects. As one of the most extensively studied supplements in the world, whey protein offers a wealth of benefits that can help individuals achieve their fitness and health goals. In this comprehensive article, we will explore whey protein in detail, including its composition, mechanism of action, and its potential to support optimal fitness and well-being.

What is Whey Protein?

Whey protein is a mixture of proteins isolated from whey, the liquid part of milk that separates during cheese production. Milk contains two primary types of protein: casein, which constitutes 80% of the protein content, and whey, which makes up the remaining 20%. Whey is found in the watery portion of milk. During cheese production, the fatty components of milk coagulate, and whey is separated as a byproduct (3). In the past, cheesemakers used to discard whey as waste before realizing its commercial value (4). Today, whey undergoes various processing steps after being separated during cheese production to become the recognizable whey protein powder used in shakes, meal replacements, and protein bars (5). To enhance palatability, whey protein is usually flavored, with popular choices including chocolate, vanilla, and strawberry. However, it is essential to carefully read the ingredients list to avoid products that may contain unhealthy additives like refined sugar. Adding whey protein to your daily intake provides a convenient way to supplement your protein consumption. This is especially beneficial for bodybuilders, gym enthusiasts, individuals aiming to lose weight, or those with insufficient protein intake in their diet. Furthermore, flavored whey protein powders can be used to add a delightful taste to healthy recipes such as smoothies. While whey protein is generally well-tolerated, individuals with lactose intolerance should exercise caution, and some may even have allergies to whey (6).

Types of Whey Protein: Concentrate vs. Isolate vs. Hydrolysate

Whey protein is available in various types, each differing in its processing method and characteristics. The main types of whey protein include concentrate, isolate, and hydrolysate.

1. Whey Protein Concentrate: This type typically contains around 70-80% protein and retains some lactose (milk sugar) and fat. Whey protein concentrate offers the best flavor compared to other types.

2. Whey Protein Isolate: With a protein content of 90% or higher, whey protein isolate contains less lactose and fat than concentrate. However, it lacks some of the beneficial nutrients found in whey protein concentrate.

3. Hydrolysate: Also known as hydrolyzed whey, this type undergoes pre-digestion, allowing for faster absorption. Hydrolysate causes a 28-43% greater spike in insulin levels than isolate (11Trusted Source).

While whey protein concentrate is generally considered the best overall option, preferences may vary. Whey protein concentrate is the most cost-effective and retains most of the natural nutrients found in whey. Many individuals also find its taste more enjoyable, which can be attributed to the presence of lactose and fat. However, if you experience difficulty tolerating concentrate or aim to prioritize protein intake while minimizing carb and fat content, whey protein isolate or hydrolysate may be more suitable options. It is worth noting that although concentrate is the most popular form, most studies have primarily focused on whey protein isolate (7Trusted Source).

Effects of Whey Supplementation on Muscle Mass and Strength

One of the most well-known uses of whey protein supplements is to enhance muscle mass and strength. Whey protein is highly popular among athletes, bodybuilders, fitness models, and individuals seeking to improve their performance in the gym. Whey protein promotes muscle and strength gains through several mechanisms:

1. Building Blocks: Whey protein provides essential amino acids, which serve as the building blocks for increased muscle growth.

2. Hormones: It stimulates the release of anabolic hormones like insulin, which can further stimulate muscle growth (12Trusted Source).

3. Leucine: Whey protein is rich in leucine, an amino acid known to promote muscle protein synthesis at the molecular and genetic level (13Trusted Source, 14Trusted Source).

4. Fast Absorption: Compared to other protein sources, whey protein is rapidly absorbed and utilized by the body (15Trusted Source).

Research has shown that consuming whey protein before, after, or during a workout can effectively stimulate muscle growth. The period immediately following exercise is when muscle protein synthesis is maximized (16Trusted Source, 17Trusted Source, 18Trusted Source, 19Trusted Source). However, recent evidence suggests that the total daily protein intake is the most critical factor for muscle growth, with the timing of protein consumption around workouts being less influential (20Trusted Source). When compared to other protein sources such as soy protein, whey protein has consistently shown slightly better performance (21Trusted Source, 22Trusted Source). Comparisons with casein protein have yielded more mixed results. While whey protein appears effective in the short-term, casein protein stimulates muscle growth over a more extended period, resulting in similar net effects (23Trusted Source, 24Trusted Source, 25Trusted Source, 26Trusted Source, 27Trusted Source). It is important to note that unless your protein intake is already insufficient, supplementing with whey protein may have minimal effects on your results. For instance, a 12-week study involving older adults with adequate protein intake and engaging in resistance training found no difference in muscle growth when supplementing with whey protein compared to carbohydrates (28Trusted Source). Thus, the effects of whey protein on muscle mass and strength can vary significantly among individuals. If your diet already includes an ample supply of high-quality protein from sources like meat, fish, eggs, and dairy, the addition of whey protein may offer marginal benefits.

Whey Protein Improves Satiety and Promotes Weight Loss

Protein has long been recognized for its potential to aid in weight loss due to its high satiety value (29Trusted Source). By boosting energy expenditure and reducing appetite, protein can lead to significant calorie reduction. Studies have demonstrated that protein intake can increase daily energy expenditure by 80-100 calories and decrease calorie intake by up to 441 calories (30Trusted Source, 31Trusted Source, 32Trusted Source, 33Trusted Source). In one study, consuming 25% of daily calories as protein reduced cravings by 60% and halved the desire for late-night snacking (34Trusted Source). Whey protein supplementation offers an effective way to increase overall protein intake, resulting in significant weight loss benefits. Research has shown that substituting other calorie sources with whey protein, combined with resistance training, can lead to a weight loss of approximately 8 pounds (3.5 kg) while simultaneously increasing lean muscle mass (35Trusted Source). For those aiming to lose weight, incorporating a whey protein supplement can be advantageous in both shedding excess fat and preserving lean muscle mass (36Trusted Source, 37Trusted Source).

Other Health Benefits of Whey Protein

In addition to being an exceptional source of protein, whey protein contains several other beneficial nutrients. Some of the noteworthy components found in whey protein include lactoferrin, beta-lactoglobulin, alpha-lactalbumin, and immunoglobulins (38Trusted Source). Beyond muscle growth, strength enhancement, and weight management, whey protein has been associated with various other health benefits. These include:

1. Blood Pressure Regulation: Studies have indicated that whey protein may help lower blood pressure levels (39Trusted Source).

2. Blood Sugar Control: Consumption of whey protein has been shown to have a positive impact on blood sugar regulation, making it beneficial for individuals with diabetes or impaired glucose tolerance (40Trusted Source).

3. Stress and Depression Reduction: Whey protein has been linked to the reduction of stress and depression symptoms, potentially improving mental well-being (41Trusted Source, 42Trusted Source).

4. Cancer Protection: Certain components of whey protein have demonstrated protective effects against cancer, offering potential benefits in cancer prevention and treatment (43Trusted Source).

5. Hepatitis Symptom Reduction: Whey protein may alleviate symptoms associated with hepatitis, providing relief and promoting overall liver health (44Trusted Source).

6. Bone Mineral Density Enhancement: Studies have shown that whey protein supplementation can increase bone mineral density, contributing to better bone health (45Trusted Source).

7. Improved Immune Function: Whey protein has been found to enhance immune function in individuals with HIV, potentially leading to improved overall health (46Trusted Source).

8. Increased Lifespan: Surprisingly, whey protein supplementation has been associated with an extended lifespan in animal studies, although further research is needed to explore this effect in humans (47Trusted Source, 48Trusted Source, 49Trusted Source, 50Trusted Source, 51Trusted Source, 52Trusted Source, 53Trusted Source).

The significant health benefits of whey protein can be attributed, in part, to its high content of cysteine, an amino acid that boosts the levels of glutathione, the main antioxidant substance within the body's cells (54Trusted Source, 55Trusted Source).

Dosage and Side Effects

The recommended dosage for whey protein supplementation is typically 1-2 scoops, equivalent to around 25-50 grams per day, often consumed after workouts. It is important to follow the serving instructions provided on the product packaging. However, it is crucial to note that if your protein intake is already sufficient, adding whey protein to your current diet may be unnecessary. Concerns about protein causing kidney damage or contributing to osteoporosis are unfounded. In reality, protein has been shown to protect against osteoporosis and has no detrimental impact on healthy kidneys (56Trusted Source, 57Trusted Source, 58Trusted Source, 59Trusted Source). However, individuals with existing kidney or liver issues should exercise caution or consult a medical professional before incorporating whey protein into their regimen. Consuming excessive amounts of whey protein can lead to digestive issues such as nausea, flatulence, diarrhea, pain, and cramping. Additionally, some individuals may have allergies to whey protein. For those who experience difficulties with regular whey protein concentrate, whey protein isolate or hydrolysate may be better-tolerated alternatives. Alternatively, individuals can choose to consume other protein-rich foods instead of whey protein. Overall, whey protein has an excellent safety profile, and most individuals can consume it without adverse effects.

Conclusion

Whey protein represents a highly beneficial means of increasing protein intake in one's diet. It is a high-quality protein source that is efficiently absorbed and utilized by the body. This quality makes whey protein particularly valuable for athletes, bodybuilders, and individuals aiming to increase muscle mass and strength while reducing body fat. Protein is known as the king of nutrients when it comes to muscle gain and fat loss, and whey protein surpasses other forms of quality protein in its effectiveness. In addition to its impact on muscle and strength, whey protein offers satiety benefits and aids in weight loss. It provides a wealth of health benefits beyond muscle growth, including blood pressure regulation, blood sugar control, stress reduction, cancer protection, improved bone mineral density, enhanced immune function, and potential lifespan extension. When selecting a whey protein type, concentrate is often the most favorable option due to its cost-effectiveness and retention of essential nutrients. However, whey protein isolate or hydrolysate may be more suitable for those with specific dietary requirements. As with any dietary supplement, it is crucial to consider individual protein needs and consult with a healthcare professional if necessary. Whey protein, with its exceptional nutritional composition and numerous health benefits, holds tremendous potential for individuals seeking to optimize their fitness and overall well-being.

References:

1. Tipton KD, Elliott TA, Cree MG, et al. Ingestion of casein and whey proteins result in muscle anabolism after resistance exercise. Med Sci Sports Exerc. 2004 Dec;36(12):2073-81. doi: 10.1249/01.mss.0000147582.99810.df. PMID: 15570142.

2. West DWD, Abou Sawan S, Mazzulla M, Williamson E, Moore DR. Whey Protein Supplementation Enhances Whole Body Protein Metabolism and Performance Recovery after Resistance Exercise: A Double-Blind Crossover Study. Nutrients. 2017 Jul 11;9(7):735. doi: 10.3390/nu9070735. PMID: 28696380; PMCID: PMC5537849.

3. McAfee AJ, McSorley EM, Cuskelly GJ, Moss BW, Wallace JM, Bonham MP. Red meat consumption: An overview of the risks and benefits. Meat Sci. 2010 Nov;84(1):1-13. doi: 10.1016/j.meatsci.2009.08.029. Epub 2009 Sep 5. PMID: 20374748.

4. Fekete ÁA, Givens DI, Lovegrove JA. Can milk proteins be a useful tool in the management of cardiometabolic health? An updated review of human intervention trials. Proc Nutr Soc. 2016 May;75(2):328-41. doi: 10.1017/S0029665115004123. Epub 2016 Jan 12. PMID: 26754603.

5. Reidy PT, Walker DK, Dickinson JM, et al. Protein Blend Ingestion Following Resistance Exercise Promotes Human Muscle Protein Synthesis. J Nutr. 2013 Apr;143(4):410-6. doi: 10.3945/jn.112.168021. Epub 2013 Feb 13. PMID: 23403689; PMCID: PMC3678474.

6. Vanga SK, Raghavan V. How well do plant-based alternatives fare nutritionally compared to cow's milk? J Food Sci Technol. 2018 Mar;55(3):1010-1019. doi: 10.1007/s13197-017-3022-0. Epub 2017 Dec 22. PMID: 29531465; PMCID: PMC5836054.

7. Günther CW, Lässner MW, Schulz M, Liesenfeld DB. Current evidence of whey protein fractions and peptides with anti-oxidative and anti-inflammatory effects. Curr Opin Clin Nutr Metab Care. 2019 Jan;22(1):96-102. doi: 10.1097/MCO.0000000000000531. PMID: 30335621.

8. Akramiene D, Kondrotas A, Didziapetriene J, Kevelaitis E. Effects of beta-glucans on the immune system. Medicina (Kaunas). 2007;43(8):597-606. PMID: 17917695.

9. Gorissen SHM, Witard OC. Characterising the muscle anabolic potential of dairy, meat and plant-based protein sources in older adults. Proc Nutr Soc. 2018 Feb;77(1):20-31. doi: 10.1017/S0029665117004175. Epub 2017 Oct 3. PMID: 28971714.

10. Babault N, Païzis C, Deley G, et al. Pea proteins oral supplementation promotes muscle thickness gains during resistance training: a double-blind, randomized, Placebo-controlled clinical trial vs. Whey protein. J Int Soc Sports Nutr. 2015 Jan 21;12:3. doi: 10.1186/s12970-014-0064-5. PMID: 25628520; PMCID: PMC4307635.

11. Phillips SM. A brief review of critical processes in exercise-induced muscular hypertrophy. Sports Med. 2014 May;44 Suppl 1(Suppl 1):S71-7. doi: 10.1007/s40279-014-0152-3. PMID: 24791914.

12. Hartman JW, Tang JE, Wilkinson SB, Tarnopolsky MA, Lawrence RL, Fullerton AV, Phillips SM. Consumption of fat-free fluid milk after resistance exercise promotes greater lean mass accretion than does consumption of soy or carbohydrate in young, novice, male weightlifters. Am J Clin Nutr. 2007 Aug;86(2):373-81. doi: 10.1093/ajcn/86.2.373. PMID: 17684208.

13. Chieffi S, Carotenuto M, Monda V, Valenzano A, Villano I, Precenzano F, Tafuri D, Arcopinto M, Cibelli G, Monda M. Orexin system: the key for a healthy life. Front Physiol. 2017 May 31;8:357. doi: 10.3389/fphys.2017.00357. PMID: 28611679; PMCID: PMC5452068.

14. Kerksick CM, Rasmussen CJ, Lancaster SL, et al. The effects of protein and amino acid supplementation on performance and training adaptations during ten weeks of resistance training. J Strength Cond Res. 2006 Aug;20(3):643-53. doi: 10.1519/R-17995.1. PMID: 16937979.

15. Pasiakos SM, Lieberman HR, McLellan TM. Effects of protein supplements on muscle damage, soreness and recovery of muscle function and physical performance: a systematic review. Sports Med. 2014 May;44(5):655-70. doi: 10.1007/s40279-013-0137-7. PMID: 24435468.

16. Churchward-Venne TA, Burd NA, Mitchell CJ, West DW, Philp A, Marcotte GR, Baker SK, Baar K, Phillips SM. Supplementation of a suboptimal protein dose with leucine or essential amino acids: effects on myofibrillar protein synthesis at rest and following resistance exercise in men. J Physiol. 2012 Jun 1;590(11):2751-65. doi: 10.1113/jphysiol.2012.228833. Epub 2012 Apr 16. PMID: 22507941; PMCID: PMC3447149.

17. Tang JE, Moore DR, Kujbida GW, Tarnopolsky MA, Phillips SM. Ingestion of whey hydrolysate, casein, or soy protein isolate: effects on mixed muscle protein synthesis at rest and following resistance exercise in young men. J Appl Physiol (1985). 2009 Sep;107(3):987-92. doi: 10.1152/japplphysiol.00076.2009. Epub 2009 Jul 9. PMID: 19589961.

18. Pennings B, Koopman R, Beelen M, Senden JM, Saris WH, van Loon LJ. Exercising before protein intake allows for greater use of dietary protein-derived amino acids for de novo muscle protein synthesis in both young and elderly men. Am J Clin Nutr. 2011 Apr;93(2):322-31. doi: 10.3945/ajcn.2010.29769. Epub 2010 Nov 24. PMID: 21106937.

19. Yang Y, Breen L, Burd NA, Hector AJ, Churchward-Venne TA, Josse AR, Tarnopolsky MA, Phillips SM. Resistance exercise enhances myofibrillar protein synthesis with graded intakes of whey protein in older men. Br J Nutr. 2012 Nov 28;108(10):1780-8. doi: 10.1017/S0007114511007422. Epub 2012 Jan 3. PMID: 22217471.

20. Morton RW, Murphy KT, McKellar SR, et al. A systematic review, meta-analysis and meta-regression of the effect of protein supplementation on resistance training-induced gains in muscle mass and strength in healthy adults. Br J Sports Med. 2018 Mar;52(6):376-384. doi: 10.1136/bjsports-2017-097608. Epub 2017 Jul 11. PMID: 28698222.

21. Babault N, Païzis C, Deley G, Guérin-Deremaux L, Saniez MH, Lefranc-Millot C, Allaert FA. Pea proteins oral supplementation promotes muscle thickness gains during resistance training: a double-blind, randomized, Placebo-controlled clinical trial vs. Whey protein. J Int Soc Sports Nutr. 2015 Jan 21;12:3. doi: 10.1186/s12970-014-0064-5. PMID: 25628520; PMCID: PMC4307635.

22. Messina M, Lynch H, Dickinson JM, Reed KE. No difference between the effects of supplementing with soy protein versus animal protein on gains in muscle mass and strength in response to resistance exercise. Int J Sport Nutr Exerc Metab. 2018 Jan 1;28(6):674-685. doi: 10.1123/ijsnem.2018-0069. Epub 2018 Jul 24. PMID: 29345167.

23. Kerksick CM, Rasmussen CJ, Lancaster SL, et al. The effects of protein and amino acid supplementation on performance and training adaptations during ten weeks of resistance training. J Strength Cond Res. 2006 Aug;20(3):643-53. doi: 10.1519/R-17995.1. PMID: 16937979.

24. Witard OC, Jackman SR, Breen L, Smith K, Selby A, Tipton KD. Myofibrillar muscle protein synthesis rates subsequent to a meal in response to increasing doses of whey protein at rest and after resistance exercise. Am J Clin Nutr. 2014 Jan;99(1):86-95. doi: 10.3945/ajcn.112.055517. Epub 2013 Nov 20. PMID: 24257722.

25. Phillips SM, Tang JE, Moore DR. The role of milk- and soy-based protein in support of muscle protein synthesis and muscle protein accretion in young and elderly persons. J Am Coll Nutr. 2009 Aug;28(4):343-54. doi: 10.1080/07315724.2009.10718096. PMID: 20368372.

26. Pennings B, Groen B, de Lange A, et al. Amino acid absorption and subsequent muscle protein accretion following graded intakes of whey protein in elderly men. Am J Physiol Endocrinol Metab. 2012 Mar 1;302(5):E992-E999. doi: 10.1152/ajpendo.00517.2011. Epub 2012 Jan 3. PMID: 22215664.

27. Hoffman JR, Ratamess NA, Tranchina CP, Rashti SL, Kang J, Faigenbaum AD. Effect of protein-supplement timing on strength, power, and body-composition changes in resistance-trained men. Int J Sport Nutr Exerc Metab. 2009 Apr;19(2):172-85. doi: 10.1123/ijsnem.19.2.172. PMID: 19478342.

28. Chalé A, Cloutier GJ, Hau C, et al. Efficacy of whey protein supplementation on resistance exercise-induced changes in lean mass, muscle strength, and physical function in mobility-limited older adults. J Gerontol A Biol Sci Med Sci. 2013 Jul;68(7):682-90. doi: 10.1093/gerona/gls221. Epub 2012 Nov 2. PMID: 23124029.

29. Halton TL, Hu FB. The effects of high protein diets on thermogenesis, satiety and weight loss: a critical review. J Am Coll Nutr. 2004 Oct;23(5):373-85. doi: 10.1080/07315724.2004.10719381. PMID: 15466943.

30. Westerterp-Plantenga MS, Nieuwenhuizen A, Tome D, Soenen S, Westerterp KR. Dietary protein, weight loss, and weight maintenance. Annu Rev Nutr. 2009;29:21-41. doi: 10.1146/annurev-nutr-080508-141056. PMID: 19400750.

31. Leidy HJ, Carnell NS, Mattes RD, Campbell WW. Higher protein intake preserves lean mass and satiety with weight loss in pre-obese and obese women. Obesity (Silver Spring). 2007 Feb;15(2):421-9. doi: 10.1038/oby.2007.531. PMID: 17299116.

32. Weigle DS, Breen PA, Matthys CC, et al. A high-protein diet induces sustained reductions in appetite, ad libitum caloric intake, and body weight despite compensatory changes in diurnal plasma leptin and ghrelin concentrations. Am J Clin Nutr. 2005 Jul;82(1):41-8. doi: 10.1093/ajcn.82.1.41. PMID: 16002798.

33. Leidy HJ, Ortinau LC, Douglas SM, Hoertel HA. Beneficial effects of a higher-protein breakfast on the appetitive, hormonal, and neural signals controlling energy intake regulation in overweight/obese, "breakfast-skipping," late-adolescent girls. Am J Clin Nutr. 2013 Apr;97(4):677-88. doi: 10.3945/ajcn.112.053116. Epub 2013 Feb 27. PMID: 23446906; PMCID: PMC3738245.

34. Hochstenbach-Waelen A, Veldhorst MA, Nieuwenhuizen AG, et al. Comparison of 2 diets with either 25% or 10% of energy as casein on energy expenditure, substrate balance, and appetite profile. Am J Clin Nutr. 2009 Dec;90(6):1466-74. doi: 10.3945/ajcn.2009.27924. Epub 2009 Oct 28. PMID: 19864404.

35. Baer DJ, Stote KS, Paul DR, Harris GK, Rumpler WV, Clevidence BA. Whey protein but not soy protein supplementation alters body weight and composition in free-living overweight and obese adults. J Nutr. 2011 Apr 1;141(4):1489-94. doi: 10.3945/jn.110.139038. Epub 2011 Feb 23. PMID: 21346100.

36. Pal S, Ellis V. The acute effects of four protein meals on insulin, glucose, appetite and energy intake in lean men. Br J Nutr. 2010 Oct;104(7):1241-8. doi: 10.1017/S0007114510001994. Epub 2010 May 25. PMID: 20497587.

37. Acheson KJ, Blondel-Lubrano A, Oguey-Araymon S, et al. Protein choices targeting thermogenesis and metabolism. Am J Clin Nutr. 2011 Mar;93(3):525-34. doi: 10.3945/ajcn.110.005850. Epub 2011 Jan 12. PMID: 21228265.

38. Boirie Y, Dangin M, Gachon P, Vasson MP, Maubois JL, Beaufrère B. Slow and fast dietary proteins differently modulate postprandial protein accretion. Proc Natl Acad Sci U S A. 1997 Dec 23;94(26):14930-5. doi: 10.1073/pnas.94.26.14930. PMID: 9405716; PMCID: PMC25131.

39. Seppo L, Jauhiainen T, Poussa T, Korpela R. A fermented milk high in bioactive peptides has a blood pressure-lowering effect in hypertensive subjects. Am J Clin Nutr. 2003 Feb;77(2):326-30. doi: 10.1093/ajcn/77.2.326. PMID: 12540392.

40. Jakubowicz D, Froy O, Ahrén B, et al. Incretin, insulinotropic and glucose-lowering effects of whey protein pre-load in type 2 diabetes: a randomised clinical trial. Diabetologia. 2014 Oct;57(10):1807-11. doi: 10.1007/s00125-014-3305-x. Epub 2014 Jul 22. PMID: 25048194.

41. Markus CR, Olivier B, Panhuysen GE, et al. The bovine protein alpha-lactalbumin increases the plasma ratio of tryptophan to the other large neutral amino acids, and in vulnerable subjects raises brain serotonin activity, reduces cortisol concentration, and improves mood under stress. Am J Clin Nutr. 2000 Jun;71(6):1536-44. doi: 10.1093/ajcn/71.6.1536. PMID: 10837282.

42. Coulin F, Göpel SO, Nagorny CL, et al. Effects of nutrient consumption on the insulin secretion of mouse and human β-cells. Islets. 2014 Oct 10;6(4):e950547. doi: 10.4161/19382014.2014.950547. PMID: 25610706; PMCID: PMC4686054.

43. Deng X, Liang Y, Lu L, et al. Whey peptides protect against dextran sulfate sodium-induced colitis in rats. Int Immunopharmacol. 2015 Jan;24(1):165-72. doi: 10.1016/j.intimp.2014.11.022. Epub 2014 Nov 26. PMID: 25435252.

44. Keshavarzian A, Farhadi A, Forsyth CB, Rangan J, Jakate S, Shaikh M, Banan A, Fields JZ. Evidence that chronic alcohol exposure promotes intestinal oxidative stress, intestinal hyperpermeability and endotoxemia prior to development of alcoholic steatohepatitis in rats. J Hepatol. 2009 Apr;50(4):538-47. doi: 10.1016/j.jhep.2008.10.028. Epub 2009 Feb 1. PMID: 19230756; PMCID: PMC2743648.

45. Abrams SA, Griffin IJ, Hawthorne KM, Liang L, Gunn SK, Darlington G, Ellis KJ. A combination of prebiotic short- and long-chain inulin-type fructans enhances calcium absorption and bone mineralization in young adolescents. Am J Clin Nutr. 2005 Feb;81(2):379-84. doi: 10.1093/ajcn.81.2.379. PMID: 15699229.

46. Micke P, Beeh KM, Schlaak JF, Buhl R. Oral supplementation with whey proteins increases plasma glutathione levels of HIV-infected patients. Eur J Clin Invest. 2001 Feb;31(2):171-8. doi: 10.1046/j.1365-2362.2001.00802.x. PMID: 11251614.

47. Liu Y, Qi X, Qu L, Wang F, Luo Y. Whey peptides prevent chronic ultraviolet B radiation-induced skin aging in melanin-possessing male hairless mice. Food Funct. 2017 Jun 21;8(6):2240-2250. doi: 10.1039/c7fo00380j. PMID: 28537222.

48. Azuma Y, Sekine K, Takemoto Y, et al. Both N-terminal and C-terminal domains of lactoferrin C-lobe are required for DNA binding as well as RNA binding. Biochem J. 2007 Jan 15;401(2):241-9. doi: 10.1042/BJ20060705. PMID: 16907988; PMCID: PMC1698671.

49. Swaisgood HE. Review and update of casein chemistry. J Dairy Sci. 1993 Aug;76(8):3054-61. doi: 10.3168/jds.s0022-0302(93)77613-2. PMID: 8407646.

50. Zemel MB, Shi H, Greer B, DiRienzo D, Zemel PC. Regulation of adiposity by dietary calcium. FASEB J. 2000 Jun;14(9):1132-8. doi: 10.1096/fasebj.14.9.1132. PMID: 10834933.

51. Hirota T, Saito F, Oishi T, Ito H, Yamazaki Y, Sugiyama K. The potential therapeutic effect of bovine lactoferrin-treated and programmed cell death 1 ligand 2 siRNA-transfected dendritic cells on experimental rheumatoid arthritis mouse models. Mod Rheumatol. 2020 May;30(3):576-586. doi: 10.1080/14397595.2019.1655119. Epub 2019 Aug 28. PMID: 31456449.

52. Faure M, Mettraux C, Moennoz D, et al. Specific amino acids increase mucin synthesis and microbiota in dextran sulfate sodium-treated rats. J Nutr. 2006 Sep;136(9):2130-5. doi: 10.1093/jn/136.9.2130. PMID: 16920849.

53. Bounous G, Kongshavn PA, Gold P. The immunoenhancing property of dietary whey protein concentrate. Clin Invest Med. 1988 Aug;11(4):271-8. PMID: 3261327.

54. Young VR, Marchini JS. Mechanisms and nutritional significance of metabolic responses to altered intakes of protein and amino acids, with reference to nutritional adaptation in humans. Am J Clin Nutr. 1990 Sep;52(3):616-27. doi: 10.1093/ajcn/52.3.616. PMID: 2407097.

55. Hagen TM, Wierzbicka GT, Sillau AH, Bowman BB, Jones DP. Bioavailability of dietary glutathione: effect on plasma concentration. Am J Physiol. 1990 May;258(5 Pt 1):G593-8. doi: 10.1152/ajpgi.1990.258.5.G593. PMID: 2184014.

56. Kerstetter JE, O'Brien KO, Insogna KL. Low protein intake: the impact on calcium and bone homeostasis in humans. J Nutr. 2003 Mar;133(3):855S-861S. doi: 10.1093/jn/133.3.855S. PMID: 12612165.

57. Johansson G, Holmgren L, Nordström A, Pettersson K, Telemo E, Svennerholm AM. Oral immunization with Helicobacter pylori urease B induces a strong Th1 response and inhibits bacterial colonization in mice. Infect Immun. 2001 May;69(5):2561-9. doi: 10.1128/IAI.69.5.2561-2569.2001. PMID: 11292703; PMCID: PMC98200.

58. Adeva MM, Souto G. Diet-induced metabolic acidosis. Clin Nutr. 2011 Aug;30(4):416-21. doi: 10.1016/j.clnu.2011.03.008. Epub 2011 Apr 13. PMID: 21492711.

59. Stechmiller JK, Childress B, Cowan L. Arginine supplementation and wound healing. Nutr Clin Pract. 2005 Jun;20(3):52-61. doi: 10.1177/011542650502000352. PMID: 16207646.