Monday, February 9, 2015

Fending off Sarcopenia in Aging Adults

Good nutrition throughout the life cycle can ward off illness and keep one healthy into their golden years.  We are entering an era where the Baby Boomers are retiring and continuing to stay active.

Older adults make up a greater percentage of the American population than ever before (1). Sarcopenia, or the loss of muscle mass with age, is a common condition faced by this age group. Sarcopenia alone can impact an older adult’s quality of life and limit his or her ability to complete activities of daily living (think basic self-care tasks). Furthermore, when combined with obesity, sarcopenia may increase the risk of insulin resistance (2). Therefore, it is important that we, as nutrition professionals, promote nutritional strategies shown to maintain muscle mass throughout the lifespan. Together, nutrition therapy and exercise can improve body composition with age and help prevent the deterioration of skeletal muscle mass and function.  

From a nutrition perspective, adequate protein intake is essential. However, there is more to it than just overall protein intake throughout the day. Research has shown that older adults have a blunted muscle protein synthesis response following the intake of 20 grams of protein or less (3,4). However, young and old muscles have similar rates of muscle protein synthesis following the ingestion of 30 grams of protein (5).  Because of this, the amount of protein eaten at each meal is especially important in older adults. In a 2009 review, Paddon-Jones et al. modeled the typical pattern of protein intake versus the optimal pattern of protein intake in older adults (see picture below) (6).

With this information in mind, we should encourage 25-30 grams of protein at each meal in order to promote maximal protein synthesis in older adults. If this recommendation cannot be met (because of a lack of appetite or a physical disability), older adults may also benefit from additional protein or essential amino acid supplements between meals (>10 g essential amino acids) (7). Let’s keep Grandma moving!

Emily Riddle is a Ph.D. student in molecular nutrition at Cornell University. She earned her B.S. in nutritional science from the Pennsylvania State University and her M.S./RD from the University of Utah. Although she is currently a doctorate student, she remains extremely invested in dietetics and nutrition education, and she has a strong interest in translating scientific findings into relevant messages for consumers and clients. You can contact her at or find her tweeting at @ERiddle146.

Works Cited
1) West, L.A., et al., 65+ in the United States: 2010, in Current Population Reports. 2014, United States Census Bureau. p. 23-212.
2) Srikanthan, P., A.L. Hevener, and A.S. Karlamangla, Sarcopenia exacerbates obesity-associated insulin resistance and dysglycemia: findings from the National Health and Nutrition Examination Survey III. PLoS One, 2010. 5(5): p. e10805.
3) Katsanos, C.S., et al., Aging is associated with diminished accretion of muscle proteins after the ingestion of a small bolus of essential amino acids. Am J Clin Nutr, 2005. 82(5): p. 1065-73.
5) Symons, T.B., et al., Aging does not impair the anabolic response to a protein-rich meal. Am J Clin Nutr, 2007. 86(2): p. 451-6.
6) Paddon-Jones, D. and B.B. Rasmussen, Dietary protein recommendations and the prevention of sarcopenia. Curr Opin Clin Nutr Metab Care, 2009. 12(1): p. 86-90.
7) Paddon-Jones, D., et al., Exogenous amino acids stimulate human muscle anabolism without interfering with the response to mixed meal ingestion. Am J Physiol Endocrinol Metab, 2005. 288(4): p. E761-7.