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April 15, 2009   

Rethinking protein recommendations

New understandings on protein needs for optimal health in adulthood should be considered in improving current dietary recommendations according to a recent article in Nutrition and Metabolism (March 13, 2009). The review outlines errors of omission in the current recommended dietary allowance (RDA) and dietary recommendations for protein as well as new knowledge about protein needs.

A growing body of research indicates that most adults could benefit from protein intakes above the RDA, which represents the minimum daily intake for active healthy adults. Current evidence suggests that protein intakes above the RDA are beneficial for maintaining muscle function and mobility throughout life and in the treatment of obesity, heart disease, type 2 diabetes, the metabolic syndrome, osteoporosis and sarcopenia.

While the acceptable macronutrient distribution range in the current Dietary Reference Intakes presents protein need as a percentage of energy intake in proportion to carbohydrates and fats, adult protein needs are proportional to body weight. Protein needs become more important during periods of reduced food intake, such as weight loss with lower energy intake, or during periods of recovery after illness or during aging. Sufficient protein with each meal also helps to enhance satiety and maintain healthy muscles and bones during aging.

For your practice:

The article emphasizes that it is important to understand that absolute protein requirements (grams per day) relate to body weight and remain virtually constant across all energy intakes. Thus, if energy intakes are reduced for weight management or as people age, recommending protein as a percentage of energy without attention to absolute protein requirements is a serious and potentially harmful error. Since protein needs are a function of lean tissue mass, they must increase as a percentage of low energy diets.

Want to learn more?

Read the full article, Dietary Guidelines Should Reflect New Understandings about Adult Protein Needs, by Layman DK. Nutr Metab, 2009; 6:12.

Read the abstract for another recent article by Layman et al., A Moderate-Protein Diet Produces Sustained Weight Loss and Long-Term Changes in Body Composition and Blood Lipids in Obese Adults. J Nutr. 2009; 139: 514-521. Click on the “Podcast” link on that page to the listen to the recent Journal of Nutrition interview with Dr. Donald Layman about this study in which he also addresses questions on the safety of higher protein intakes.

See, our Nutrition Perspective newsletters for health professionals: The Satiating Power of Protein (May 2008) and Protein – Can Higher Intakes Benefit Health? (August 2005). Each includes a 2-page client fact sheet.