The proteins of human breast milk are the most important endocrine signaling system that promotes neonatal growth by increasing the release of insulin, insulin-like growth factor-1 (IGF-1), and the leucine-mediated mammalian target of rapamycin complex 1- (mTORC1) signaling of pancreatic β-cells. Remarkably, the branched-chain amino acids (BCAAs) leucine, isoleucine, and valine are involved in the growth-promoting effects of milk, protein biosynthesis, and metabolism because they physiologically stimulate insulin secretion The present study sought to investigate the effects of the combination of whey protein and casein in the ratio of 80:20 ("whey protein: casein" or "casein: whey protein") as breast milk proportion on the peak and the period of the permanence of branched-chain amino acids in the blood circulation, final metabolites of protein metabolism and delayed onset muscle soreness (DOMS) after a single bout of fasting or a resistance exercise session.
The present study investigated the effects of the association of WP and casein in the ratio of 80:20, a similar ratio of human breast milk, on blood branched-chain amino acids (BCAAs) profile by HPLC technique, markers of protein metabolism (creatinine, urea, and urine nitrogen) and delayed onset muscle soreness (DOMS) after a single bout of resistance exercise. A double-blind, crossover and acute study was conducted with ten men (age 29 ± 8 y; BMI: 25.4 ± 2.9 Kg/m2; 77 ± 12 kg; 1.74 ± 0.09 m) that were randomly assigned to five supplementation treatments: WP - whey protein; CAS - casein; WP/CAS - 80% WP/20% CAS; CAS/WP - 80% CAS/ 20% WP; PLA - placebo. Participants were submitted to the following evaluations: performance sessions, blood collection for each session for the BCAAs profile determination, two food records, 3-days assessment of DOMS (24h, 48h, 72h) after each treatment.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
BASIC_SCIENCE
Masking
DOUBLE
Enrollment
10
Protein supplementation using 20 grams of whey protein or casein mix. Acute Resistance training, 10 sets of 10 reps at 85% of 1Maximum repetition
Placebo supplementation using 20 grams of Maltodextrin. Acute Resistance training, 10 sets of 10 reps at 85% of 1Maximum repetition
10 sets of 10 repetitions at 85% of 1 Maximum repetition in leg press exercise
University of São Paulo, School of Physical Education and Sports of Ribeirão Preto.
Ribeirão Preto, São Paulo, Brazil
Change from baseline in plasma amino acids concentration
Blood sample collected for analysis of BCAA concentration after blend protein or placebo supplementation expressed in (µmol/L)
Time frame: 5 weeks
Change from baseline in 1RM test
Change of training load using RPE, time and load expressed in (a.u)
Time frame: 5 weeks
Change in protein metabolism
Change in nitrogen excretion, and nitrogen balance after protein supplementation expressed in (g/24 hours)
Time frame: 5 weeks
Changes from baseline in macronutrient intake
Change of macronutrient intake were calculated pre and post treatment expressed in (g/24 hours)
Time frame: 5 weeks
Change in delayed onset muscle soreness
Change from baseline the delayed onset muscle soreness pre, post, 24 hours, 48 hours and 72 hours after treatment expressed in (a.u)
Time frame: 5 weeks
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