Protein Review--Protein Quality and Optimal Health

Here is another one for ya. Be sure to check out yesterday's post if you missed it.

Protein quality assessment: impact of expanding understanding of protein and amino acid needs for optimal health.

Millward DJ, Layman DK, Tomé D, Schaafsma G.

School of Biomedical and Molecular Sciences, University of Surrey, Surrey, UK.

Protein quality describes characteristics of a protein in relation to its ability to achieve defined metabolic actions. Traditionally, this has been discussed solely in the context of a protein's ability to provide specific patterns of amino acids to satisfy the demands for synthesis of protein as measured by animal growth or, in humans, nitrogen balance. As understanding of protein's actions expands beyond its role in maintaining body protein mass, the concept of protein quality must expand to incorporate these newly emerging actions of protein into the protein quality concept. New research reveals increasingly complex roles for protein and amino acids in regulation of body composition and bone health, gastrointestinal function and bacterial flora, glucose homeostasis, cell signaling, and satiety. The evidence available to date suggests that quality is important not only at the minimum Recommended Dietary Allowance level but also at higher intakes. Currently accepted methods for measuring protein quality do not consider the diverse roles of indispensable amino acids beyond the first limiting amino acid for growth or nitrogen balance. As research continues to evolve in assessing protein's role in optimal health at higher intakes, there is also need to continue to explore implications for protein quality assessment.

Am J Clin Nutr. 2008 May;87(5):1576S-1581S.

Publication Types:

* Research Support, Non-U.S. Gov't

* Review

PMID: 18469291 [PubMed - indexed for MEDLINE]

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Protein Review Article-Impact on Glycemic Control During Weight Loss

Greetings and thanks for stopping back to check in. Until about the first week of July you will probably be seeing even more studies than usual here as I will be posting some studies I find interesting as I am currently up to my neck in all sorts of studies working on my PhD writtens.

Here is a great review that you can get the whole article too from their website. Dr Layman has done lots for great work in the area of protein research. Abstract below
enjoy

Dietary protein impact on glycemic control during weight loss.

Layman DK, Baum JI.

Department of Food Science and Human Nutrition, University of Illinois Urbana-Champaign, Urbana, IL 61801, USA. dlayman@uiuc.edu

Diets with higher protein (1.5 g x kg(-1) x d(-1)) and reduced carbohydrates (120 to 200 g/d) appear to enhance weight loss due to a higher loss of body fat and reduced loss of lean body mass. While studies of prolonged use of moderate protein diets are not available, short-term studies report beneficial effects associated with increased satiety, increased thermogenesis, sparing of muscle protein loss, and enhanced glycemic control. Combined impacts of a moderate protein diet are likely derived from lower carbohydrates resulting in lower postprandial increase in blood glucose and lower insulin response, and higher protein providing increased BCAA leucine levels and gluconeogenic substrates. A key element in the diet appears to be the higher intake of BCAA leucine with unique regulatory actions on muscle protein synthesis, modulation of the insulin signal, and sparing of glucose use by stimulation of the glucose-alanine cycle. This review focuses on the contributions of leucine and the BCAA to regulation of muscle protein synthesis and glycemic control.

Publication Types:
* Review

PMID: 15051856 [PubMed - indexed for MEDLINE]

Research Review: Protein Synthesis Part II; Exercise Nutrition

Round 2 of super geeky exercise physiology studies for ya! If you missed part 1, be sure to check it out HERE.

So what do any of these studies mean in real lift? Good question and glad you asked.

Here are a few take aways Any food around your training session is better than nothing! Heck, even chocolate milk is better than nothing and a candy bar preexercise did not decrease performance! Now I think there are a few better choices, but you get the idea that proper timing of training nutrition is important.

Nutrition Recommendations for Exercise

• If you have eaten within about 2 hours or so, no preexercise beverage is needed
• If not, about 30 grams protein and 30-60 grams carbs preexercise is a good place to start
• One scoop of whey protein powder and 1 scoop of Biotest Surge works well
  
• Consume within about 30 minutes preexercise (again listen to your body and your goal is to train and feel fine and not yack!)
• Water during weight training session
• If you are doing endurance work that is longer than an hour, ingest a dilute carb beverage such as Gatorade
  
• Post training, same beverage as preexercise (30g pro with 30-60 grams carbs)
• Eat your normal meal within about 1-1.5 hours.
  
• Note---this is just a GENERAL guideline and is by no means absolute--just a good starting point

Drop me a line and let me know your results!
On to the studies!

Influence of concurrent exercise or nutrition countermeasures on thigh and calf muscle size and function during 60 days of bed rest in women.

Conclusion: “The nutrition countermeasure was not effective in offsetting lower limb muscle volume or strength loss, and actually promoted thigh muscle volume loss. The concurrent aerobic and resistance exercise protocol was effective at preventing thigh muscle volume loss, and thigh and calf muscle strength loss. While the exercise protocol offset approximately 75% of the calf muscle volume loss, modification of this regimen is needed.”

The effects of nutritional supplementation throughout an endurance run on leucine kinetics during recovery.

Conclusion: “Although consuming milk during the run affected whole-body leucine kinetics, the benefits of such a practice for athletes remain unclear. Additional studies are needed to determine whether protein supplementation during exercise can optimize protein utilization during recovery.”

International Society of Sports Nutrition position stand: protein and exercise.

Conclusion: “The seven points related to the intake of protein for healthy, exercising individuals constitute the position stand of the Society. They have been approved by the Research Committee of the Society.”

Exercise training increases branched-chain oxoacid dehydrogenase kinase content in human skeletal muscle.

Conclusion: “It is concluded that the increased protein content of BCOAD (branched-chain oxoacid dehydrogenase complex) kinase may be involved in the mechanism for reduced BCOADa (branched-chain oxoacid dehydrogenase complex activation) after exercise training in human skeletal muscle. These data also highlight differences in models used to study the regulation of skeletal muscle BCAA (Branched Chain Amino Acids) metabolism, since exercise training was previously reported to increase BCOADa (branched-chain oxoacid dehydrogenase complex activation) during exercise and decrease BCOAD (branched-chain oxoacid dehydrogenase complex) kinase content in rats (Fujii H, Shimomura Y, Murakami T, Nakai N, Sato T, Suzuki M, Harris RA. Biochem Mol Biol Int 44: 1211-1216, 1998).”

Effects of a supplementation during exercise and recovery

Conclusion: “The protein hydrolysate treatment induced adaptations that may promote a decrease in fatigue during exercises, potentially explained by changes in parameters used to represent oxidative damage and antioxidant status at rest and changes in lactate metabolism.”

Branched-chain amino acids and arginine supplementation attenuates skeletal muscle proteolysis induced by moderate exercise in young individuals.

Conclusion: “The results suggest that endurance exercise at moderate intensity enhances proteolysis in working muscles, and a single oral intake of 2 g of BCAA (branched-chain amino acids) with Arg (arginine) at onset of exercise effectively suppresses exercise-induced skeletal muscle proteolysis.”

Postexercise whole-body protein turnover response to three levels of protein intake.

Conclusion: “Findings from the study show that variations in protein intake can alter plasma amino acid levels and modulate rates of WBPTO (whole-body protein turnover) after exercise. Additionally, a lower protein intake was associated with decreased rates of WBPTO (whole-body protein turnover) after exercise."