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Wednesday, February 26, 2014

Whey protein intake: 20g per serving may be enough. But is 40g wasteful? By Veeraj Vic Goyaram

Supplement Science Update


Whey protein intake: 
20g per serving may be enough. But is 40g wasteful?
By Veeraj Vic Goyaram
How much is ideal?
Often when downing a good whey protein shake you may wonder whether you are drinking enough or too much. Whey protein isn't cheap these days and it is essential to know the dose that gives you the most anabolic bang for your protein buck. Some (but not all) supplement sellers may tell you that more is better because this means more business to them. We can't blame them but we can open your eyes on certain topics. That's why today we bring you this update on protein supplement research that specifically looked at the effect of whey protein dose on muscle protein synthesis. 

Scientists from the Universities of Exeter, Birmingham, Stirling and Derby (Witard et al., 2014) teamed up and studied the effect of several doses of whey protein on the muscle protein synthesis response.

The subjects were healthy males with lifting experience and weighed on average 80kg with 15% bodyfat. They were given either 0, 10, 20 or 40g whey protein both at rest and after training. The results, summarised below, were quite interesting:


A. Protein synthesis increased with ingestion of 20g protein compared to 0g and 10g
Muscle protein synthesis (MPS) increased with increasing protein ingestion such that ingestion of 10 and 20g of protein led to greater MPS (50% and 30% respectively) than when no protein was consumed (0 g).

Figure 1: 20g whey protein gives better MPS than 10g and o g.
However, 40g whey protein did not increase MPS significantly
B. Taking 40g whey protein didn't further increase MPS than with ingestion of 20 g. You can see in Fig. 1 that MPS with 40g is not greater than 20g. This means that for twice the protein expense you are not getting anything in return. 

B. Taking 40g whey protein leads to greater amino acid oxidation  as shown by greater rates of amino acid oxidation and urea production (Fig 2A and 2B). 
Figure 2: A. 40g whey protein leads to greater amino acid breakdown (oxidation) and Urea production (Graph B) 
The "Muscle Full effect"
This study agrees with other studies which showed no greater rate of MPS with increasing protein ingestion. For example, studies by Symons et al., (2009) showed that a protein meal (equivalent to 113 g lean beef, 30 g protein, and 10 g EAAs) was equally effective as a 340 g serving of lean beef (90 g protein and 30 g EAAs) for the stimulation of MPS.


What explains the fact that MPS is not increased with 40g protein is the “muscle full effect” which is based on the notion that once a limit of amino acid delivery to muscle is achieved the cells will no longer use amino acids for MPS.

Some thoughts
  • 20g protein per serving gives you the best anabolic bang for your protein buck. This is the minimum you must aim for at each intake. 
  • Is consuming more than 20g wasteful? I don't think so. The stimulation of MPS is not the only thing that the body needs protein for. Your body needs the protein to make hormones, enzymes, antibodies and other protein-based molecules. I personally go for about 40-50g per intake x 4 meals per day. I don't think that my body ended up absorbing only 20g x 4 meals=80g protein for the day. I was making muscular gains. 
  • I am often "guilty" of the practice of eating all of my day's meals in just two sittings, morning and evening (100g protein per intake). My body composition improved. I was seeing the same results as splitting the day's food intake into 2 meals vs. eating the same amount in 4 meals. A meta-analysis by Dr. Brad Schoenfeld (Schoenfeld et al., 2015) showed that lean body mass was retained quite well in dieters who ate less (1-2) meals as well as more (3-4) meals. 

    • Note that older individuals may need more than 20g of protein per serving because their body respond less well to protein, a phenomenon called "anabolic resistance". About 40g/ intake is recommended for them. 
    Anything you didn't understand? Was the article too complicated? I am open to suggestions!
    Email me on vicgoyaram@gmail.com
     or write in comments below!

    References


    Schoenfeld BJ et alEffects of meal frequency on weight loss and body composition: a meta-analysis Brad Jon Nutrition Reviews. 73(2):69–82, 2015

    Symons TB, Sheffield-Moore M, Wolfe RR, Paddon-Jones D. A moderate serving of high-quality protein maximally stimulates skeletal muscle protein synthesis in young and elderly subjects. J Am Diet Assoc 2009;109:1582–6.

    Witard OC, Jackman SR, Breen L, Smith K, Selby A and 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 99: 86-95, 2014.


    My Bio: I am a Mauritian originally from Roche Bois, Port Louis and now based in Cape Town, South Africa where I am busy with my postgraduate studies in molecular biology of exercise. My research, supervised by Prof. Edward Ojuka and Dr. Tertius Kohn, looks at the influence of nutrition and exercise in gene expression in muscle, research which is relevant and applicable to exercising individuals, sports persons and diabetic individuals. The knowledge that I share with you stems from my 18 years of experience in bodybuilding and 8 years (and counting) of university education in the field. I have also published work in the American Journal of Physiology: Endocrinology and Metabolism (2012, 2014), International Journal of Sport Nutrition and Exercise Metabolism (2013) and co-authored two book chapters on exercise and diabetes. I also presented my research work at the 2012 International Sports and Exercise Nutrition Conference (UK). I am grateful to each and everyone at the UCT Research Unit for Exercise Science and Sports Medicine. "Knowledge without sharing is worth nothing"
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