Wednesday, September 25, 2013

Should Athletes Increase Protein Above Recommended Levels?


Many athletes will increase their protein intake in order to increase lean mass and strength.  There are many conflicting messages on whether or not this macronutrient increase actually works.  Hoffman et al ran a stratified study to determine if increasing an athlete's protein intake does improve his body composition and strength. 
In the study, the researchers took 23 collegiate strength/power athletes for a 12-week resistance training study.  The athletes were divided into three stratified groups.  BL consumed below recommended levels of protein at 1.0-1.4g/kg/day.  RL consumed the recommended levels of protein at 1.6-1.8g/kg/day.  AL consumed above the recommended protein levels at >2.0g/kg/day. (1)  The researchers noted that the total energy intake for each group was below the recommended levels. (1)
According to common marketing in supplement stores and magazines, the AL group should have seen market increases in strength and improvement in body composition.  However, the researchers discovered no changes in body composition, to include body mass, lean body mass, and percent body fat, from the PRE in all three groups.  The researchers did discover a significant increase in strength, but, again, it was in all three groups.  Also, the researchers discovered no significant hormone changes from PRE in all three groups. (1) 
Given the results from the Hoffman study, there is no benefit for an athlete to stray from the recommended protein intake levels.  It is important for an athlete to remain lean, but it is also important for the athlete to remain healthy.  Consuming a well-rounded diet with nutritionally dense foods will help an athlete, meet his goals and stay lean and strong.  Being sure to follow a balanced workout of strength and cardiovascular exercise appropriate for the sport, will help the athlete increase strength and power without the need to consume more than the recommended allowance of any one macronutrient.  Being consistent in diet and training are more important than consuming too much or too little of any particular macronutrient.

1.  Hoffman, Jay R.; Ratamess, Nicholas A.; Kang, Jie; Falvo, Michael; Faigenbaum, Avery.  Effect of Protein Intake on Strength, Body Composition, and Endocrine Changes in Strength/Power Athletes.  Journal of the International Society of Sports Nutrition 2006; 3: 12-18.

Sunday, September 22, 2013

And some more about protein supplements...



Here are summaries of two more studies covering whey protein supplements.  In the first, Pasiakos et al conducted a thirteen day, randomized, crossover study to assess postexercise muscle protein synthesis (MPS), whole-body protein turnover, and anabolic intracellular signaling responses to the effect of essential amino acids in supplements (1).  The eight adult volunteers were tested on days 8 and 13.  The two groups were given two different concentrations of leucine:  Group 1, the experimental group, were given 3.5g leucine (L-EAA) and Group 2, the control group, was given 1.87g leucine (EAA) (1).  Both groups consumed their supplements during exercise.  The leucine for both groups was dissolved in 500mL of water with an artificial sweetener (1).
The volunteers were active-duty military personnel who regularly participated in both endurance and resistance exercise at least 3-4 days per week.  They were all recreationally fit with no medications, no injuries, and no abnormalities (1).  While the study was run with 9 men and 1 woman, the data used in the report was for 7 men and 1 woman (1).  The volunteers were directed to do two separate bouts of cycle for 60 minutes at 60% VO2 peak (1).
The researchers discovered that the muscle protein synthesis was 33% greater after L-EAA than EAA.  Also, the whole-body protein breakdown and synthesis was down and the oxidation was up for the L-EAA group (1).  The mammalian target of rapamycin phosphorylation was up with the L-EAA group 30 minutes after exercise (1).  The researchers concluded that L-EAA supplementation increases leucine availability and spares endogenous protein stores to a greater extent during endurance-type exercises (1).
In the second study, West et al measured the effect of whey protein on myofibrillar protein synthesis (MPS) after exercise (2).  This study observed eight men who were recreationally active, not endurance athletes.  They were randomly assigned into two groups:  Group 1 was given a single bolus of 25g (BOLUS) and Group 2 was given small, “pulsed” drinks of ten drinks of 2.5g every 20 minutes (Pulsed) (2).  The drinks were prepared in water with no additives, like artificial sweetener.  The BOLUS consisted of 12.8g EAA, 3.5g leucine, 0 carbohydrate, and 0 fat; the PULSE drinks were the same formula administered in the pulsed manner (2).
The researchers found the BOLUS increased blood essential amino acid (EAA) concentrations 162% 60 minutes after exercise, and the PULSE increased EAA 53% (2).  Also, with the BOLUS, the blood EAA concentrations were greater at the 80-minute mark.  However, the EAA concentrations were greater with PULSE at 180, 200, and 240 minutes (2).  The same results were found for blood leucine concentrations.  There was no change in insulin for PULSE, but the insulin was greater for BOLUS at 20, 40, and 60 minutes (2).
The researchers concluded that muscle anabolism was better benefitted by bulk delivery of amino acids post-exercise (2).  The researchers also speculate that more fat and/or more carbohydrates would slow protein absorption (2).
Below is the information gathered from five studies thus far.  The chart includes the dosage, timing, and form of protein for each study.  A few of the studies compared different types of proteins or different ways of administering the proteins.  I did not include conclusions from the studies in this chart; however, I will be getting to those in the next few weeks.


Protein Supplement Study Protocols


Number
Dosage
Timing
Form
Study







1
1.5g/kg
daily for 14 days
Whey or Carbohydrate
Cooke et al, 2010







2
20g
pre- or post-exercise
Whey
Tipton et al, 2007







3
237g
1 hr post workout
FF milk



237g

Whole milk
Elliot et al, 2006


393g

FF milk isocaloric with whole milk







4
3.5g
during exercise
leucine



1.87g

leucine
Pasiakos et al, 2011







5
25g-single
post exercise
Whey
West et al, 2011


25g-pulsed













1.  Pasiakos, Stefan M.; McClung, Holly L.; McChung, James P.; Margolis, Lee M.; Anderson, Nancy E.; Coutier, Gregory L.; Pikosky, Matthew A.; Rood, Jennifer C.; Fielding, Roger A.;  Young, Andrew J.  Leucine-enriched essential amino acid supplementation during moderate steady state exercise enhances postexercise muscle protein synthesis.  The American Journal of Clinical Nutrition  2011; 94: 809-818
2.  West, Daniel WD; Burd, Nicholas A.; Coffey, Vernon G; Baker, Steven K; Burke, Louise M; Hawley, John A; Moore, Daniel R; Stellingwerff, Trent; Phillips, Stuart M.  Rapid aminoacidemia enhances myofibrillar protein synthesis and anabolic intramuscular signaling responses after resistance exercise.  American Journal of Clinical Nutrition  2011; 94: 795-803

Tuesday, September 10, 2013

More about protein...


In last week’s discussion, the Cooke study was used to demonstrate how whey protein supplements enhance performance.  The Cooke study states that protein supplements providing “exogenous amino acids, especially within the first 4 hours after resistance exercise (as implemented in the study), increases protein synthesis, decreases protein breakdown, and produces a positive protein balance, thus providing an environment for muscle growth” (Cooke et al, 2010).  This week, the search was for studies that supported the use of milk-based protein, such as whey, for muscular anabolism. 
Tipton et al set up a study to examine the response of muscle protein balance when subjects consume whey proteins either before or after resistance exercise (Tipton et al, 2007).  There were both male and female subjects; seventeen total.  None of the subjects had done regular resistance training for at least five years prior to the study, and all were young and healthy (Tipton et al, 2007).  The volunteers were randomly assigned to two groups:  Group A consumed a 300-ml solution of 20g whey proteins before exercise (PRE); Group B consumed the same amount of whey protein post exercise (POST) (Tipton et al, 2007).  There was no placebo group.  Each group conducted ten sets of eight leg extension exercises. 
The researchers sampled the subjects before protein ingestion and four hours after to measure the amino acid uptake.  The researchers found that the timing of the protein ingestion had no effect; however, it was the combination of the free amino acids and carbohydrates that did have an effect on the measurements (Tipton et al, 2007).  Phenylalanine concentrations increased immediately after ingesting whey protein for both PRE and POST groups, but there was no significant difference between the PRE and the POST groups (Tipton et al, 2007).
Elliot et al set out to discover if whole foods would have an effect on muscular anabolism.  Again, the twenty-four subjects had not participated in regular resistance training in at least five years prior to the study (Elliot et al, 2006).  The subjects were randomly assigned to three groups:  1)  237g fat free milk (FM), 2) 237g whole milk (WM), and 3) 393g fat-free milk isocaloric with the whole milk (IM).  There was no placebo group.  Each group ingested their protein one hour after leg exercises, and researchers measured amino acid balance across the leg to determine net muscle protein balance (Elliot et al, 2006).  The groups were tested just before exercise and 55 minutes post-exercise; as well as, immediately prior to consuming their drink (Elliot et al, 2006).
The researchers discovered that the amino acid uptake was higher for the WM group (Elliot et al, 2006).  The threonine exchange was present in all three groups; this was measured in arterial concentrations.  The phenylalanine in muscular concentrations was present in all three groups; this was measured via biopsy of the muscular tissue (Elliot et al, 2006).  The researchers concluded that the milk ingestion stimulates phenylalanine and threonine net uptake and promotes muscular anabolism.
Both the Elliot and Tipton studies determined free amino acid concentration via GCMS and used muscle biopsies to analyze for intracellular amino acid concentrations.  All three studies used non-athletes as their subjects.  All three studies demonstrate that it is best to combine the carbohydrate with the amino acid source to stimulate net muscle protein synthesis and muscle growth, which is why the whey protein and whole milk are useful to athletic performance.


Cooke, Matthew; Rybalka, Emma; Stathis, Christos; Cribb, Paul; Hayes, Alan. Whey protein isolate attenuates strength decline after eccentrically-induced muscle damage in healthy individuals.  Journal of the International Society of Sports Nutrition 2010; 7:30
Elliot, Tabatha A; Cree, Melanie G; Sanford, Arthur P; Wolfe, Robert R.; Tipton, Kevin D.  Milk Ingestion Stimulates Net Muscle Protein Synthesis Following Resistance Exercise.  Medicine and Science in Sports and Exercise  2002; 38: 667-674
Tipton, Kevin D; Elliot, Tabatha A.; Cree, Melanie G; Aarsland, Asle A; Sanford, Arthur P; Wolfe, Robert R.  Stimulation of net muscle protein synthesis by whey protein ingestion before and after exercise.  American Journal of Physiology-Endocrinology and Metabolism  2007; 292: E71-E76

Monday, September 2, 2013

Protein Supplements as an Ergogentic Aid: Do They Really Work?


An ergogenetic aid is “any training technique, mechanical device, nutritional practice, pharmacological method, or psychological technique that can improve exercise performance capacity and/or enhance training adaptations” (Kreider et al, 2010).  Protein supplements are an ergogentic aid that have been heavily advertised to the general public and athletes as a great way to build muscle and enhance abilities.  However, there are three important questions to ask when evaluating these supplements:  1)  Is the theory plausible?  In other words, can protein supplements enhance performance and reduce muscle breakdown?  2) Is there scientific evidence to support the theory?  3)  Is the supplement safe and legal?  (Kreider et al, 2010)   
Most sources agree that an athlete should strive to get adequate protein from whole foods before turning to a supplemental form.  However, protein supplements may be a more convenient way for the athlete to consume his or her protein requirements, especially for vegetarian athletes (Dunford & Doyle, 2012).  A high-quality protein supplement is considered safe and effective at the recommended doses (Dunford & Doyle, 2012).
It has been found that whey, casein, or soy supplements are effective for the maintenance, repair, and synthesis of skeletal muscle proteins and can enhance maintenance and net gains in skeletal muscle (ADA, 2009).   Cooke et al conducted a study on whey protein isolate and found that adding whey protein supplements to their subjects’ diets increased isometric strength in the knees of those subjects (Cooke et al, 2010).   This study took seventeen untrained males and randomly selected them into two categories:  whey protein and carbohydrate.  The subjects were given 1.5g/kgbw/d for 14 days.   The study was run with a 95% confidence interval.  The subjects were tested with the leg press, leg extension, leg flexion, and checked for muscle damage (Cooke et al, 2010). 
The Cooke study supports the theory that a high-quality protein supplement enhances performance for athletes when additional protein is needed.  Athletes commonly go above the RDA of 0.8g/kgbw for protein, and endurance and ultra-endurance athletes should consume more protein due to an increase in protein oxidation (ADA, 2009).   Protein supplements providing “exogenous amino acids, especially within the first 4 hours after resistance exercise (as implemented in the [Cooke] study), increases protein synthesis, decreases protein breakdown, and produces a positive protein balance, thus providing an environment for muscle growth” (Cooke et al, 2010).  It is the use of a high-quality protein with appropriate amino acids that aids in the rebuilding, repairing, and endurance of the muscle.
While protein supplements may be beneficial to strength and muscle repair, it is still important to look for quality sources.  The best sources of protein supplements are casein, whey, mild and egg proteins, and colostrum (Kreider et al, 2010).  When choosing a protein supplement, it is also important to consider the amino acids in the supplement for maximum benefits and health (Dunford & Doyle, 2012).  It is also important to use a high-quality protein as was used in the Cooke study.  It is also important to remember that although protein supplements are considered safe and effective, they may not be necessary for the general public but are beneficial to the strength and endurance athlete.

ADA (2009)  Nutrition and Athletic Performance.  Journal of American Dietetic Association 2009; 109:509-527.
Cooke, Matthew; Rybalka, Emma; Stathis, Christos; Cribb, Paul; Hayes, Alan (2010)  Whey protein isolate attenuates strength decline after eccentrically-induced muscle damage in healthy individuals.  Journal of the International Society of Sports Nutrition 2101, 7:30
Dunford, Marie & Doyle, J. Andrew (2012)  Nutrition for Sport and Exercise, 2nd ed.  Wadsworth Cengage Learning:  California
Kreider, Richard B.; Wilborn, Colin D.; Taylor, Lem; Campbell, Bill; Almada, Anthony; Collins, Rick; Cooke, Matthew; Earnest, Conrad; Greenwood, Mike; Kalman, Douglas; Kerksick, Chad; Kleiner, Susan; Leutholtz, Brian; Lopez, Hector; Lowrey, Lonnie; Mendel, Ron; Smith, Abbie; Spano, Marie; Wildman, Robert; Willoughby, Darryn; Ziegenfuss, Tim; Anfonio, Jose (2010).  ISSN exercise and sport nutrition review:  research and recommendations.  Journal of the International Society of Sports Nutrition 2010, 7:7