Abstract:
Physical activity increases protein catabolism and decreases
plasma essential amino acids concentrations. Determining plasma amino
acids concentrations is the method of choice for assessment of amino acids
requirements of body organs. Few researches have been published about
the effect of protein supplements, containing amino acids and other useful
substances, on plasma essential amino acids concentrations in resistance
athletes. This study was carried out to investigate the effect of whey
protein supplementation on plasma essential amino acids concentrations,
after resistance exercise in healthy athletes. In this clinical trial,
changes of plasma essential amino acids concentrations were studied after
1 h exercise training and whey protein supplementation in 32 healthy volunteers
(16 in each of supplement and placebo groups). Each day, whey protein
supplement (20 g) and placebo (the same amount of starch) were consumed
after training. Participants exercised with 80% 1 RM, basically on stationary
circuit principal, for 1 h. Blood specimens were taken in fasting state,
immediately after exercise and 1 h after supplement consumption. Essential
amino acids concentrations were analyzed by HPLC. Statistical analysis
were carried out using Student t-test and paired t-test. Treonine concentration
increased significantly after exercise (p<0.05), but there was no difference
between the two study groups. After supplementation, histidine concentration
was unchanged in both groups. Treonine, arginine, methionine, valine,
isoleucine and leucine concentrations increased significantly and phenylalanine
concentration increased nonsignificantly in the supplement group. Treonine,
methionine, valine, phenylalanine, isoleucine and leucine concentrations
decreased significantly, but downward trend of arginine was not significant.
Differences between the two groups were significant. The present study
showed that 20 g day-1 of whey protein supplement is effective
on plasma essential amino acids concentrations and compensated for their
post exercise decrease.
S. Eslami, M. Karandish, S.M. Marandi and A. Zand-Moghaddam, 2009. The Study of Whey Protein Supplementation on Plasma Essential Amino
Acids Concentrations after Resistance Exercise in Healthy Young Athletes. Journal of Biological Sciences, 9: 145-151.
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