Abstract
The differential ability of various milk protein fractions to stimulate muscle protein synthesis (MPS) has been previously described, with whey protein generally considered to be superior to other fractions. However, the relative ability of a whole milk protein to stimulate MPS has not been compared to whey. Sixteen healthy middle-aged males ingested either 20 g of milk protein (n = 8) or whey protein (n = 8) while undergoing a primed constant infusion of ring 13C6 phenylalanine. Muscle biopsies were obtained 120 min prior to consumption of the protein and 90 and 210 min afterwards. Resting myofibrillar fractional synthetic rates (FSR) were 0.019% ± 0.009% and 0.021% ± 0.018% h−1 in the milk and whey groups respectively. For the first 90 min after protein ingestion the FSR increased (p < 0.001) to 0.057% ± 0.018% and 0.052% ± 0.024% h−1 in the milk and whey groups respectively with no difference between groups (p = 0.810). FSR returned to baseline in both groups between 90 and 210 min after protein ingestion. Despite evidence of increased rate of digestion and leucine availability following the ingestion of whey protein, there was similar activation of MPS in middle-aged men with either 20 g of milk protein or whey protein.
Highlights
Ageing is associated with a loss of muscle mass, strength, and physical function; a condition which is termed sarcopenia [1]
The identification of cost effective and readily available proteins which lead to maximal stimulation of muscle protein synthesis (MPS) in the middle aged population may be important in the development of dietary interventions to maintain muscle mass and prevent or delay sarcopenia
The secondary objectives were to assess the effects of these proteins on mammalian target of rapamycin complex 1 (mTOR) pathway activation and to test the hypothesis that peak blood leucine and essential amino acid (EAA) content is the primary determinant of MPS in response to protein feeding
Summary
Ageing is associated with a loss of muscle mass, strength, and physical function; a condition which is termed sarcopenia [1]. The identification of cost effective and readily available proteins which lead to maximal stimulation of muscle protein synthesis (MPS) in the middle aged population may be important in the development of dietary interventions to maintain muscle mass and prevent or delay sarcopenia. Whey protein ingestion has been shown to result in a greater post exercise MPS response compared to micellar casein [15,19], when casein was processed, the results were equivocal [10,14,15]. The secondary objectives were to assess the effects of these proteins on mTOR pathway activation and to test the hypothesis that peak blood leucine and essential amino acid (EAA) content is the primary determinant of MPS in response to protein feeding
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
