1. Protein Supplements for Maintaining Muscle in Older Individuals
A study of whey protein versus a blended protein
Allyson Schattel, Michael Borack, Blake Rasmussen
Department of Nutrition and Metabolism, The University of Texas Medical Branch at
Galveston
Sarcopenia is the loss of muscle mass, strength, and function that is related to aging. The goal of
this study is to create a strategy to prevent sarcopenia. The most common protein supplements
contain the milk-protein whey. A new blended protein (25% whey, 25% soy, 50% casein) will be
tested against whey in the elderly. Our hypothesis is that the blended protein supplement will
maintain amino acids in the blood for a longer period of time than whey alone, which will enable
the muscles to grow for a longer duration. We will test whey protein versus the blended protein
in 20 male subjects, aged 55-75 years of age. At the beginning of the study day, the human
subject will receive an amino acid infusion. Throughout the day, the subject has 24 blood draws,
18 breath collections, and 5 muscle biopsies taken. The subject also performs resistance exercise
(8 sets of 10 repetitions on leg extensions) and intakes the protein supplement one hour
following exercise. To measure the rate of protein synthesis, a Gas Chromatography-Mass
Spectrometer will be used to calculate the level of amino acids in the blood and muscle samples.
The blended protein group is expected to contain higher levels of blood amino acids two to four
hours after the supplement is taken resulting in higher rates of muscle protein synthesis during
this period. The protein blend will hopefully prevent the onset of sarcopenia in older populations.