Training en eiwit om gezond ouder te worden

Rationale: The progressive loss of skeletal muscle mass with aging, or sarcopenia, has a major impact on our health care system due to increased morbidity and a greater need for hospitalization and/or institutionalization. It is clearly established that a combination of a resistance exercise program and adequate dietary protein intake are both effective measures to stimulate protein synthesis and counteract sarcopenia. With regards to optimally stimulating muscle protein synthesis, it is also understood that the short time period immediately following a resistance exercise session is the most opportune time to ingest a bolus of dietary protein. What is less understood, however, is the optimal amount of dietary protein that is required to maximize the stimulation of post-exercise muscle protein synthesis in elderly individuals.

Objective: To identify the amount of dietary protein that will optimally stimulate post-exercise muscle protein synthesis in the older population.

Study design: double-blind, placebo-controlled intervention study

Study population: 60 healthy lean (BMI 18.5-30 kg/m2) older males (age: 55-80 y)

Intervention: A beverage (500 mL) containing milk protein in the amount of 0, 15, 30, 45 g protein or 15 g + 1.5 g leucine (n=12 per group) will be ingested immediately after a single resistance exercise session. The exercise bout will consist of a 5-minute warm-up on a cycle ergometer, followed by 3 sets of chest press and lat pulldown and 4 sets of leg-press and leg-extension. Muscle biopsies will be taken and blood will be drawn at several time points during the day.

Main study parameters/endpoints: Primary study parameters are the rates of muscle protein synthesis. Secondary study parameters include whole-body protein synthesis, breakdown, oxidation, and net balance.

We hypothesize that ingesting 30 g of milk protein will have an optimal effect in stimulating post-exercise muscle protein synthesis when compared to 0, 15 and 45 g milk protein. In addition, we hypothesize that co-ingestion of 1.5 g additional free leucine with 15 g of milk protein will be as effective in stimulating post-exercise muscle protein synthesis compared to 30 g of milk protein.

t=0 hrs drink, t=0 and t=6hrs muscle biopsy.
12 blood draws.

Exercise bout and protein drink