Responses of Muscle and Whole-body Protein Turnover to Ingestion of Differing Doses of Whey and Soy Protein With and Without Resistance Exercise in Elderly Men

When we age, we lose muscle. It is not exactly clear why this happens, but we do know that this muscle loss can increase health risks and lead to health problems. Lifting weights (i.e. performing resistance exercise) and proper nutrition, in particular eating enough high quality protein, can help slow the loss of muscle mass or potentially even reverse it. Protein and resistance exercise are thought to do this by stimulating your muscle to make more proteins and/or potentially by slowing down the rate at which your body breaks proteins down. Whey protein is a high quality protein isolated from milk and is known to stimulate new protein synthesis for all proteins in your body. However, to date, the effect that whey protein has on muscle protein synthesis, particularly in the elderly has yet to be determined. Thus the purposes of this study are: 1) to determine if whey is an effective source of protein that will stimulate muscle protein synthesis in the elderly, similar to what we have previously seen in young persons; 2) to determine the smallest amount of whey protein to consume to maximally stimulate your muscle to make new proteins; 3) to see if performing resistance exercise will augment the increase in new muscle protein synthesis with whey consumption; and 4) to try and found out if whey is more effective than soy protein in stimulating new muscle protein synthesis and suppressing muscle protein breakdown in the elderly, similar to what we have previously seen in young persons