Whey Protein
The effects of protein and amino acid supplementation on performance and training adaptations during ten weeks of resistance training.
Kerksick CM, Rasmussen CJ, Lancaster SL, Magu B, Smith P, Melton C, Greenwood M,
Almada AL, Earnest CP, Kreider RB.
J Strength Cond Res. 2006 Aug;20(3):643-53
The purpose of this study was to examine the effects of whey protein supplementation on body composition, muscular strength, muscular endurance, and anaerobic capacity during 10 weeks of resistance training. Thirty-six resistance-trained males (31.0 +/- 8.0 years, 179.1 +/- 8.0 cm, 84.0 +/- 12.9 kg, 17.8 +/- 6.6%) followed a 4 days-per-week split body part resistance training program for 10 weeks. Three groups of supplements were randomly assigned, prior to the beginning of the exercise program, in a double-blind manner to all subjects: 48 g per day (g.d(-1)) carbohydrate placebo (P), 40 g.d(-1) of whey protein + 8 g.d(-1) of casein (WC), or 40 g.d(-1) of whey protein + 3 g.d(-1) branched-chain amino acids + 5 g.d(-1) L-glutamine (WBG). At 0, 5, and 10 weeks, subjects were tested for fasting blood samples, body mass, body composition using dual-energy x-ray absorptiometry (DEXA), 1 repetition maximum (1RM) bench and leg press, 80% 1RM maximal repetitions to fatigue for bench press and leg press, and 30-second Wingate anaerobic capacity tests. No changes (p > 0.05) were noted in all groups for energy intake, training volume, blood parameters, and anaerobic capacity. WC experienced the greatest increases in DEXA lean mass (P = 0.0 +/- 0.9; WC = 1.9 +/- 0.6; WBG = -0.1 +/- 0.3 kg, p < 0.05) and DEXA fat-free mass (P = 0.1 +/- 1.0; WC = 1.8 +/- 0.6; WBG = -0.1 +/- 0.2 kg, p < 0.05). Significant increases in 1RM bench press and leg press were observed in all groups after 10 weeks. In this study, the combination of whey and casein protein promoted the greatest increases in fat-free mass after 10 weeks of heavy resistance training. Athletes, coaches, and nutritionists can use these findings to increase fat-free mass and to improve body composition during resistance training. PMID: 16937979
Whey Protein but Not Soy Protein Supplementation Alters Body Weight and Composition in Free-Living Overweight and Obese Adults
Baer DJ, Stote KS, Paul DR, Harris GK, Rumpler WV, Clevidence BA.
J. Nutrition 2011 Aug;141(8):1489-94
A double-blind, randomized clinical trial was conducted to determine the effect of consumption of supplemental whey protein (WP), soy protein (SP), and an isoenergetic amount of carbohydrate (CHO) on body weight and composition in freeliving overweight and obese but otherwise healthy participants. Ninety overweight and obese participants were randomly assigned to 1 of 3 treatment groups for 23 wk: 1) WP; 2) SP (each providing ;56 g/d of protein and 1670 kJ/d); or 3) an isoenergetic amount of CHO. Supplements were consumed as a beverage twice daily. Participants were provided no dietary advice and continued to consume their free-choice diets. Participants’ body weight and composition data were obtained monthly. Dietary intake was determined by 24-h dietary recalls collected every 10 d. After 23 wk, body weight and composition did not differ between the groups consuming the SP and WP or between SP and CHO; however, body weight and fat mass of the group consuming theWPwere lower by 1.8 kg (P,0.006) and 2.3 kg (P,0.005), respectively, than the group consuming CHO. Lean body mass did not differ among any of the groups. Waist circumference was smaller in the participants consuming WP than in the other groups (P , 0.05). Fasting ghrelin was lower in participants consuming WP compared with SP or CHO. Through yet-unknown mechanisms, different sources of dietary protein may differentially facilitate weight loss and affect body composition. Dietary recommendations, especially those that emphasize the role of dietary protein in facilitating weight change, should also address the demonstrated clinical potential of supplemental WP. PMID: 21677076
Effects of a whey protein supplementation on intrahepatocellular lipids in obese female patients.
Bortolotti M, Maiolo E, Corazza M, Van Dijke E, Schneiter P, Boss A, Carrel G, Giusti V, Lê KA, Quo Chong DG, Buehler T, Kreis R,Boesch C, Tappy L.
Clinical Nutrition. 2011 Aug;30(4):494-8
High protein diets have been shown to improve hepatic steatosis in rodent models and in high-fat fed humans. We therefore evaluated the effects of a protein supplementation on intrahepatocellular lipids (IHCL), and fasting plasma triglycerides in obese non diabetic women. Eleven obese women received a 60 g/day whey protein supplement (WPS) for 4-weeks, while otherwise nourished on a spontaneous diet, IHCL concentrations, visceral body fat, total liver volume (MR), fasting total-triglyceride and cholesterol concentrations, glucose tolerance (standard 75 g OGTT), insulin sensitivity (HOMA IS index), creatinine clearance, blood pressure and body composition (bio-impedance analysis) were assessed before and after 4-week WPS. IHCL were positively correlated with visceral fat and total liver volume at inclusion. WPS decreased significantly IHCL by 20.8 ± 7.7%, fasting total TG by 15 ± 6.9%, and total cholesterol by 7.3 ± 2.7%. WPS slightly increased fat free mass from 54.8 ± 2.2 kg to 56.7 ± 2.5 kg, p = 0.005). Visceral fat, total liver volume, glucose tolerance, creatinine clearance and insulin sensitivity were not changed. WPS improves hepatic steatosis and plasma lipid profiles in obese non diabetic patients, without adverse effects on glucose tolerance or creatinine clearance.
PMID: 21288612 Copyright © 2011 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.
Protein consumption following aerobic exercise increases whole-body protein turnover in older adults.
Murphy C, Miller BF.
Appl Physiol Nutr Metab. 2010 Oct;35(5):583-90.
Research measuring whole-body protein turnover (WBPT) after both exercise and nutrition has generally focused on resistance exercise; however, there is a paucity of data regarding the effect of postaerobic exercise nutrition, especially in older adults. It is not known if postexercise protein feeding has a beneficial effect on protein turnover after low- to moderate-intensity exercise. We investigated whether consuming protein plus carbohydrate (PRO) immediately after an acute bout of aerobic exercise has an additive effect over carbohydrate alone (CHO) on WBPT in older individuals. Twelve healthy older adults (age, 59 ± 4 years) were studied on 2 separate occasions after 1 h of exercise at approximately 50% of maximal rate of oxygen uptake, followed by 4 h of recovery. Immediately following exercise, subjects ingested a CHO (60 g) or an isocaloric PRO beverage (40 g carbohydrate, 20 g whey protein). Whole-body protein metabolism was determined using [1-13C]leucine infusion (60 mg prime; 75 mgh(-1) continuous), and sampling blood and expired breath. Rates of whole-body leucine appearance and oxidation, and nonoxidative leucine disposal during the third and fourth hours of postexercise recovery were higher in the PRO group (2.51 ± 0.55, 0.78 ± 0.37, and 1.71 ± 0.44 micromol kg(-1)·min(-1), respectively) than in the CHO group (1.81 ± 0.27, 0.33 ± 0.14, and 1.47 ± 0.25 micromol kg(-1)·min-1, respectively; p = 0.001). Our results indicate that consumption of a PRO beverage after aerobic exercise increased WBPT to a greater extent than a CHO beverage. PMID: 20962913
Whey protein ingestion in elderly persons results in greater muscle protein accrual than ingestion of its constituent essential amino acid content.
Katsanos CS, Chinkes DL, Paddon-Jones D, Zhang XJ, Aarsland A, Wolfe RR.
Nutr Res. 2008 Oct;28(10):651-8.
It is recognized that both whey protein (WY) and essential amino acids (EAA) are stimuli for muscle protein anabolism. The aim of the present study was to determine if the effects of WY ingestion on muscle protein accrual in elderly persons are due solely to its constituent EAA content. Fifteen elderly persons were randomly assigned to ingest a bolus of either 15 g of WY, 6.72 g of EAA, or 7.57 g of nonessential amino acids (NEAA). We used the leg arteriovenous model to measure the leg phenylalanine balance, which is an index of muscle protein accrual. Phenylalanine balance (nmol x min(-1) kg lean leg mass(-1)) during the 3.5 hours after the bolus ingestion improved in the WY (-216 +/- 14 vs -105 +/- 19; P < .05) but not in the EAA (-203 +/- 21 vs -172 +/- 38; P > .05) or NEAA groups (-203 +/- 19 vs -204 +/- 21; P > .05). The insulin response (uIU x mL(-1) 210 min(-1)) during the same period was lower in both the NEAA (48 +/- 40) and EAA (213 +/- 127) when compared to the WY (1073 +/- 229; P < .05). In conclusion, WY ingestion improves skeletal muscle protein accrual through mechanisms that are beyond those attributed to its EAA content. This finding may have practical implications for the formulation of nutritional supplements to enhance muscle anabolism in older individuals. PMID: 19083472
Whey protein concentrate (WPC) and glutathione modulation in cancer treatment.
Bounous G.
Anticancer Res. 2000 Nov-Dec;20(6C):4785-92.
The glutathione (GSH) antioxidant system is foremost among the cellular protective mechanisms. Depletion of this small molecule is a common consequence of increased formation of reactive oxygen species during increased cellular activities. This phenomenon can occur in the lymphocytes during the development of the immune response and in the muscular cells during strenuous exercise. It is not surprising that so much research has been done, and is still being done on this small tripeptide molecule. Whey protein concentrate has been shown to represent an effective and safe cysteine donor for GSH replenishment during GSH depletion in immune deficiency states. Cysteine is the crucial limiting amino acid for intracellular GSH synthesis. Animal experiments showed that the concentrates of whey proteins also exhibit anti-carcinogenesis and anticancer activity. They do this via their effect on increasing GSH concentration in relevant tissues, and may have anti-tumor effect on low volume of tumor via stimulation of immunity through the GSH pathway. It is considered that oxygen radical generation is frequently a critical step in carcinogenesis, hence the effect of GSH on free radicals as well as carcinogen detoxification, could be important in inhibiting carcinogenesis induced by a number of different mechanisms. Case reports are presented which strongly suggest an anti-tumor effect of a whey protein dietary supplement in some urogenital cancers. This non toxic dietary intervention, which is not based on the principles of current cancer chemotherapy, will hopefully attract the attention of laboratory and clinical oncologists. PMID: 11205219
Protein for exercise and recovery.
Kreider RB, Campbell B.
Phys Sportsmed. 2009 Jun;37(2):13-21.
Dietary protein is required to promote growth, repair damaged cells and tissue, synthesize hormones, and for a variety of metabolic activities. There are multiple sources of proteins available; however, animal sources of protein contain all essential amino acids and are considered complete sources of protein, whereas plant proteins lack some of the essential amino acids and are therefore classified as incomplete. There is a significant body of evidence to indicate that individuals who are engaged in intense training require more dietary protein than sedentary counterparts (ie, 1.4-2 g/kg/day). For most individuals, this level of protein intake can be obtained from a regular and varied diet. However, recent evidence indicates that ingesting protein and/or amino acids prior to, during, and/or following exercise can enhance recovery, immune function, and growth and maintenance of lean body mass. Consequently, protein and amino acid supplements can serve as a convenient way to ensure a timely and/or adequate intake for athletes. Finally, adequate intake and appropriate timing of protein ingestion has been shown to be beneficial in multiple exercise modes, including endurance, anaerobic, and strength exercise. PMID: 20048505
Protein requirements and supplementation in strength sports.
Phillips SM.
Nutrition. 2004 Jul-Aug;20(7-8):689-95.
Daily requirements for protein are set by the amount of amino acids that is irreversibly lost in a given day. Different agencies have set requirement levels for daily protein intakes for the general population; however, the question of whether strength-trained athletes require more protein than the general population is one that is difficult to answer. At a cellular level, an increased requirement for protein in strength-trained athletes might arise due to the extra protein required to support muscle protein accretion through elevated protein synthesis. Alternatively, an increased requirement for protein may come about in this group of athletes due to increased catabolic loss of amino acids associated with strength-training activities. A review of studies that have examined the protein requirements of strength-trained athletes, using nitrogen balance methodology, has shown a modest increase in requirements in this group. At the same time, several studies have shown that strength training, consistent with the anabolic stimulus for protein synthesis it provides, actually increases the efficiency of use of protein, which reduces dietary protein requirements. Various studies have shown that strength-trained athletes habitually consume protein intakes higher than required. A positive energy balance is required for anabolism, so a requirement for “extra” protein over and above normal values also appears not to be a critical issue for competitive athletes because most would have to be in positive energy balance to compete effectively. At present there is no evidence to suggest that supplements are required for optimal muscle growth or strength gain. Strength-trained athletes should consume protein consistent with general population guidelines, or 12% to 15% of energy from protein. PMID: 15212752
Effects of resistance training and protein plus amino acid supplementation on muscle anabolism, mass, and strength.
Willoughby DS, Stout JR, Wilborn CD.
Amino Acids. 2007;32(4):467-77
This study examined 10 wks of resistance training and the ingestion of supplemental protein and amino acids on muscle performance and markers of muscle anabolism. Nineteen untrained males were randomly assigned to supplement groups containing either 20 g protein (14 g whey and casein protein, 6 g free amino acids) or 20 g dextrose placebo ingested 1 h before and after exercise for a total of 40 g/d. Participants exercised 4 times/wk using 3 sets of 6-8 repetitions at 85-90% of the one repetition maximum. Data were analyzed with two-way ANOVA (p < 0.05). The protein supplement resulted in greater increases in total body mass, fat-free mass, thigh mass, muscle strength, serum IGF-1, IGF-1 mRNA, MHC I and IIa expression, and myofibrillar protein. Ten-wks of resistance training with 20 g protein and amino acids ingested 1 h before and after exercise is more effective than carbohydrate placebo in up-regulating markers of muscle protein synthesis and anabolism along with subsequent improvements in muscle performance. PMID: 16988909
Effect of whey protein isolate on strength, body composition and muscle hypertrophy during resistance training.
Hayes A, Cribb PJ.
Curr Opin Clin Nutr Metab Care. 2008 Jan;11(1):40-4
Sarcopenia (skeletal muscle wasting with aging) is thought to underlie a number of serious age-related health issues. While it may be seen as inevitable, decreasing this gradual loss of muscle is vital for healthy aging. Thus, it is imperative to investigate exercise and nutrition-based strategies designed to build a reservoir of muscle mass as early as possible. Elderly individuals are still able to respond to both resistance training and the anabolic signals provided by protein ingestion, provided specific amino acids, such as leucine, are present. Whey proteins are a rich source of these essential amino acids and rapidly elevate plasma amino acids, thus providing the foundations for preservation 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. While further work is required, particularly in elderly people, simple dietary and exercise strategies that may improve the maintenance of skeletal muscle mass will likely result in a decrease in the overall burden of a number of diseases and improve the quality of life as we age. PMID: 18090657
Whey protein ingestion in elderly persons results in greater muscle protein accrual than ingestion of its constituent essential amino acid content.
Katsanos CS, Chinkes DL, Paddon-Jones D, Zhang XJ, Aarsland A, Wolfe RR.
Nutr Res. 2008 Oct;28(10):651-8
It is recognized that both whey protein (WY) and essential amino acids (EAA) are stimuli for muscle protein anabolism. The aim of the present study was to determine if the effects of WY ingestion on muscle protein accrual in elderly persons are due solely to its constituent EAA content. Fifteen elderly persons were randomly assigned to ingest a bolus of either 15 g of WY, 6.72 g of EAA, or 7.57 g of nonessential amino acids (NEAA). We used the leg arteriovenous model to measure the leg phenylalanine balance, which is an index of muscle protein accrual. Phenylalanine balance (nmol x min(-1) kg lean leg mass(-1)) during the 3.5 hours after the bolus ingestion improved in the WY (-216 +/- 14 vs -105 +/- 19; P < .05) but not in the EAA (-203 +/- 21 vs -172 +/- 38; P > .05) or NEAA groups (-203 +/- 19 vs -204 +/- 21; P > .05). The insulin response (uIU x mL(-1) 210 min(-1)) during the same period was lower in both the NEAA (48 +/- 40) and EAA (213 +/- 127) when compared to the WY (1073 +/- 229; P < .05). In conclusion, WY ingestion improves skeletal muscle protein accrual through mechanisms that are beyond those attributed to its EAA content. This finding may have practical implications for the formulation of nutritional supplements to enhance muscle anabolism in older individuals. PMID: 19083472
Ingestion of whey hydrolysate, casein, or soy protein isolate: effects on mixed muscle protein synthesis at rest and following resistance exercise in young men.
Tang JE, Moore DR, Kujbida GW, Tarnopolsky MA, Phillips SM.
J Appl Physiol. 2009 Sep;107(3):987-92
This study was designed to compare the acute response of mixed muscle protein synthesis (MPS) to rapidly (i.e., whey hydrolysate and soy) and slowly (i.e., micellar casein) digested proteins both at rest and after resistance exercise. Three groups of healthy young men (n = 6 per group) performed a bout of unilateral leg resistance exercise followed by the consumption of a drink containing an equivalent content of essential amino acids (10 g) as either whey hydrolysate, micellar casein, or soy protein isolate. Mixed MPS was determined by a primed constant infusion of l-[ring-(13)C(6)]phenylalanine. Ingestion of whey protein resulted in a larger increase in blood essential amino acid, branched-chain amino acid, and leucine concentrations than either casein or soy (P < 0.05). Mixed MPS at rest (determined in the nonexercised leg) was higher with ingestion of faster proteins (whey = 0.091 +/- 0.015, soy = 0.078 +/- 0.014, casein = 0.047 +/- 0.008%/h); MPS after consumption of whey was approximately 93% greater than casein (P < 0.01) and approximately 18% greater than soy (P = 0.067). A similar result was observed after exercise (whey > soy > casein); MPS following whey consumption was approximately 122% greater than casein (P < 0.01) and 31% greater than soy (P < 0.05). MPS was also greater with soy consumption at rest (64%) and following resistance exercise (69%) compared with casein (both P < 0.01). We conclude that the feeding-induced simulation of MPS in young men is greater after whey hydrolysate or soy protein consumption than casein both at rest and after resistance exercise; moreover, despite both being fast proteins, whey hydrolysate stimulated MPS to a greater degree than soy after resistance exercise. These differences may be related to how quickly the proteins are digested (i.e., fast vs. slow) or possibly to small differences in leucine content of each protein. PMID: 19589961