Women over the age of 65 years have a more difficult time preserving muscle than their male counterparts, which probable impacts their ability to stay as strong and fit, according to new research published on March 26, 2008 in the open-access journal PLoS ONE.

Muscle maintenance is very important in reducing the risk of falls in the elderly, one of the major causes of premature death. After the age of 50, people lose up to 0.4% of their muscle mass every year. This makes them less mobile, more at risk for fracture, and more at risk for potentially life threatening falls.

Of elderly people who suffer a serious fall, one half die within to years. But, it is thought that the number of falls can be curtailed if muscle mass is maintained. This would keep knees and hips more properly supported and strong.

Until now, no differences had been found between men and women in muscle protein synthesis, the process the body uses to build muscle. However, recently, it has been found that the female body’s response to food and exercise declines in the mid- to late-60s. Women are at a higher risk for muscle loss because they already tend to have less muscle and more fat than men in early and middle age, so when they reach their 50s and 60s, they are already closer to becoming frail.

Now, scientists have shown for the first time that it is actually more difficult for women to replace naturally lost muscle as they get older, and this difficulty is linked to a key difference in the way men’s and women’s bodies react to food.

Experts at the Washington University School of Medicine in St Louis, Missouri, USA, and at The University of Nottingham, UK, funded by the US National Institutes of Health, studied 29 men and women aged 65-80 years old who were in good health. They examined the ability to respond to food meant to build muscle mass. It was found that post-menopausal women were less able to respond to this food than men, who were able to store protein in the muscle.

The scientists attribute this change to hormonal adjustments that occur with menopause. Specifically, the suspicion falls on estrogen, which is already known to be necessary in both women and men to help maintain bone mass. According to the researchers, these findings corroborate other preliminary results indicating that women are less able to repsond to build muscle after resistance exercise, such as lifting weights in the gym. Younger men and women, who have not reached menopause, do not seem to show any discrepancy in muscle mass potential.

Regarding this finding, Michael Rennie, Professor of Clinical Physiology at The University of Nottingham, said: “Nobody has ever discovered any mechanistic differences between men and women in muscle loss before. This is a significant finding for the maintenance of better health in old age and reducing demands on the National Health Service.”

There is advice for older women to help combat this degeneration. These new results underscore the importance of a diet sufficient in protein, including foods such as eggs, fish, chicken, and lean red meat, as well as resistance exercise.

“Rather than eating more, older people should focus on eating a higher proportion of protein in their everyday diet. In conjunction with resistance exercise, this should help to reduce the loss of muscle mass over time. There is also a case for the beneficial hormonal effect of limited HRT, although this has to be balanced against the other risks associated with such treatment,” continues Rennie.

About the Contributing Universities

Washington University School of Medicine is ranked in the US’s Top 5 Medical Schools and the World’s Top 35 universities by the U.S. News & World Report and the Times Higher (THES) World University Ranking.

The University of Nottingham is ranked in the UK’s Top 10 and the World’s Top 70 universities by the Shanghai Jiao Tong (SJTU) and Times Higher (THES) World University Rankings. It provides innovative and top quality teaching, undertakes world-changing research, and attracts talented staff and students from 150 nations. Described by The Times as Britain’s “only truly global university”, it has invested continuously in award-winning campuses in the United Kingdom, China and Malaysia. Twice since 2003 its research and teaching academics have won Nobel Prizes. The University has won the Queen’s Award for Enterprise in both 2006 (International Trade) and 2007 (Innovation – School of Pharmacy).

Its students are much in demand from ‘blue-chip’ employers. Winners of Students in Free Enterprise for three years in succession, and current holder of UK Graduate of the Year, they are accomplished artists, scientists, engineers, entrepreneurs, innovators and fundraisers. Nottingham graduates consistently excel in business, the media, the arts and sport. Undergraduate and postgraduate degree completion rates are amongst the highest in the United Kingdom.

About PLoS ONE

All works published in PLoS ONE are open-access. Everything is immediately available – to read, download, redistribute, include in databases and otherwise use – without cost to anyone, anywhere, subject only to the condition that the original authorship and source are properly attributed. Copyright is retained by the authors. The Public Library of Science uses the Creative Commons Attribution License.

PLoS ONE is the first journal of primary research from all areas of science to employ both pre- and post-publication peer review to maximize the impact of every report it publishes. PLoS ONE is published by the Public Library of Science (PLoS), the Open-access publisher whose goal is to make the world’s scientific and medical literature a public resource.

Differences in Muscle Protein Synthesis and Anabolic Signaling in the Postabsorptive State and in Response to Food in 65 – 80 Year Old Men and Women.
Smith GI, Atherton P, Villareal DT, Frimel TN, Rankin D, et al.
PLoS ONE 3(3): e1875.
doi:10.1371/journal.pone.0001875
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Written by Anna Sophia McKenney