DAIRY PROTEIN BENEFITS FOR PHYSICALLY ACTIVE PEOPLE
Volume 79, Number 3 May/June 2008
Introduction
The Recommended Dietary Allowance (RDA) for dietary protein for adults aged 19 years and older is 0.8 g/kg body weight per day (8). The Acceptable Macronutrient Distribution Range (AMDR) for protein is 10 to 35% of total calories for adults over 18 years of age (8). While the protein needs of athletes continue to be debated by some members of the scientific community, the current joint position statement on nutrition and athletic performance by the American College of Sports Medicine, the American Dietetic Association, and the Dietitians of Canada recommends protein intakes in the range of 1.2 to 1.7 g/kg body weight per day for athletes (9). In contrast to the general population which consumes an average of ~15% of calories from protein, athletes generally meet their higher protein needs by consuming 30% to 35% of calories, which is within the AMDR (10). While data are limited, protein intakes moderately above the RDA may enhance muscle mass and fat-free mass in older adults who regularly participate in resistance exercise compared to their sedentary counterparts (2,3,11,12).
Adequate intake of high-quality protein combined with resistance exercise can increase muscle mass and promote loss of fat mass (i.e., improve body composition).
Not only the amount of protein but also the type or source of protein consumed is important for maintaining or increasing muscle mass. All proteins are not created equally. The type of protein consumed may influence the results from resistance exercise due to the amino acid composition of the protein and the ability of the body to digest and metabolize the protein (6). Emerging research indicates that consuming dairy protein in close temporal proximity to resistance exercise may positively influence muscle synthesis, body composition, and ultimately physical performance (1,6).
This Digest provides an overview of protein’s role in increasing muscle mass and of the composition of dairy protein; reviews studies supporting a beneficial effect of milk (a food source of protein) and dairy proteins in recovery from resistance exercise; and discusses the role of protein and the potential metabolic advantage of dairy protein in maintaining muscle mass and slowing the progression or treating sarcopenia in older adults.
Table of Contents: