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Older women and muscle mass

Women over age 65 have a harder time preserving muscle than men of the same age, which probably affects their ability to stay strong and fit, according to research conducted at the School of Medicine and the University of Nottingham in the United Kingdom. For the first time, scientists have shown it is more difficult for older women to replace muscle that is lost naturally because of key differences in the way their bodies process food.

OLDER WOMEN HAVE A MORE DIFFICULT TIME REPLACING LOST MUSCLE THAN MEN OF THE SAME AGE. AND RESEARCHERS AT WASHINGTON UNIVERSITY SCHOOL OF MEDICINE IN ST. LOUIS AND THE UNIVERSITY OF NOTTINGHAM IN THE UNITED KINGDOM HAVE FOUND THAT ONE REASON MIGHT BE THAT THEIR BODIES DON’T USE PROTEIN FROM THE DIET AS READILY WHEN BUIDLING NEW MUSCLE. JIM DRYDEN REPORTS …

FOR THE FIRST TIME, SCIENTISTS HAVE SHOWN IT’S MORE DIFFICULT FOR OLDER WOMEN TO REPLACE LOST MUSCLE MASS BECAUSE OF KEY DIFFERENCES IN THE WAY THEIR BODIES PROCESS FOOD. WASHINGTON UNIVERSITY NUTRITION RESEARCHER BETTINA MITTENDORFER AND HER COLLEAGUES STUDIED MEN AND WOMEN BETWEEN THE AGES OF 65 AND 80.

(act) :15 o/c men do

Food intake, particularly protein in the food, is really the

major stimulus of muscle protein synthesis. We found in older

women, the response to feeding is much less, so they increase

the rate of muscle protein synthesis to much less of a degree

than men do.

MITTENDORFER SAYS FEEDING HELPS TO REBUILD MUSCLE MASS THAT’S LOST DURING FASTING. FOR THIS STUDY, MEN AND WOMEN FASTED OVERNIGHT. THE INVESTIGATORS THEN TOOK MUSCLE BIOPSIES. THEN THE RESEARCHERS GAVE THE OLDER MEN AND WOMEN A PROTEIN DRINK, ALONG WITH AN INTRAVENOUS INFUSION OF AMINO ACIDS LABELED WITH TRACER MOLECULES THAT COULD BE DETECTED EASILY IN MUSCLE TISSUE. THREE HOURS LATER, THEY TOOK ANOTHER MUSCLE BIOPSY. MITTENDORFER SAYS WOMEN START WITH LESS MUSCLE MASS THAN MEN, SO THEY REALLY CAN’T AFFORD TO LOSE ANY.

(act) :12 o/c men do

The problem is they started with less muscle, so if they

are not as efficient in using protein in the meal to build

muscle, then they might reach a threshold for critical

muscle loss for optimal function much faster than men do.

OLDER WOMEN ARE AT GREATER RISK THAN MEN FOR BOTH BONE LOSS AND FOR MUSCLE LOSS. MITTENDORFER SAYS THIS NEW STUDY POINTS OUT ONE REASON WHY THEY LOSE MUSCLE SINCE THEY CAN’T SEEM TO UTILIZE AS MUCH DIETARY PROTEIN. SHE SAYS IT MIGHT MAKE SENSE FOR OLDER WOMEN TO TRY AND CONSUME MORE PROTEIN, BUT SHE SAYS IT’S NOT CLEAR HOW MUCH IS NEEDED.

(act) :23 o/c older age

What we think is, maybe, one of the major culprits is

menopause actually, because there are some studies in

the literature, and we have done them before. In young

individuals, there doesn’t seem to be a difference between

men and women. Only as they get older, and so that’s why

we think it’s the menopause – the loss of, probably, most

likely estrogen with menopause – that’s responsible for

the deficit in older age.

MITTENDORFER SAYS SHE PLANS FUTURE STUDIES TO LOOK AT WHETHER ADJUSTING AMOUNTS OF DIETARY PROTEIN MIGHT HELP OLDER WOMEN BUILD MORE MUSCLE. SHE SAYS SHE ALSO WOULD LIKE TO LOOK AT SOME TYPE OF ESTROGEN REPLACEMENT THERAPY.

(act) :27 o/c the response

We’ll actually look at men and women, and also focus on women

in particular, with regards to dose-response relationships

that have been described in men before, but there is no such

knowledge about the women. So really, we’d recommend it more

because we think with more, you get a better response, but it’s

not really known yet. And so that’s what we plan to answer next,

and the other thing is also to really specifically look at the

effects of estrogen. If we give estrogen replacement, does it

help improve the response?

BUT SHE SAYS ANY POTENTIAL MUSCLE MASS ADVANTAGES FROM ESTROGEN WOULD NEED TO BE WEIGHED AGAINST SOME OF THE OTHER POTENTIAL DANGERS OF HORMONE REPLACEMENT. MITTENDORFER AND HER COLLEAGUES REPORTED THEIR FINDINGS IN THE JOURNAL PUBLIC LIBRARY OF SCIENCE: ONE. I’M JIM DRYDEN…

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