Researchers from the University of Minnesota Medical School recently explored why women going through menopause see a decline in muscle health.
The study determined that estrogen, the primary female sex hormone that is depleted during menopause, is a key component in the body’s ability to keep muscle stem cell health strong and so, as the body loses estrogen in later life, muscle health is also lost.
“It has long been known that male sex hormones promote muscle health, but we have been in the dark about what happens when females age,” said researcher Dawn Lowe, PhD. “What estrogen does in women in terms of reproduction has been known for decades. Now we’re learning what estrogen does in women’s muscles.”
The power behind the hormones
To see the effects of menopause on muscle health, the researchers conducted their study on mice, and then corroborated their evidence with the findings from a Finnish study that used menopausal women as its participants.
The mice in the study either had their ovaries removed, or their muscle stem cells were lacking the ability to produce estrogen.
While the researchers’ goal was to see if the mice’s stem cells would be able to regenerate on their own without estrogen, they quickly learned that this was not the case.
The lack of estrogen not only made it difficult for the muscle stem cells to repopulate, but the mice also struggled to build new muscle, with the mice experiencing anywhere from a 30 to 60 percent reduction in muscle stem cells.
When comparing evidence with the Finnish study, which included women going through menopause, both sets of researchers had similar results -- depleting levels of estrogen greatly affects the body’s ability to produce new muscle or new muscle stem cells.
In the Finnish study, researchers took muscle biopsies of women both before and after menopause, only to find that the number of stem cells was greatly impacted by the body’s estrogen levels.
The options for women to combat diminishing estrogen levels are minimal, as estrogen replacement therapy has been known to come with a slew of dangerous side effects. However, the researchers did note that a new drug is being developed that could prove to be effective in restoring the body with enough estrogen to keep healthy muscles, while also keeping the rest of the body free from harm.
Knowing how the body changes
For both men and women, growing into older age comes with several changes, and a recent study could have older people asking more questions when it comes time for vaccines.
According to a study conducted by researchers from Johns Hopkins University, the body’s immune responses to vaccines get weaker with age, as the study proved that men and women’s bodies don’t respond to vaccines the same way, and as both sexes age, the changes are amplified.
“What we show here is that the decline in estrogen that occurs with menopause impacts women’s immunity,” said researcher Sabra Klein, PhD. “Until now, this hasn’t been considered in the context of a vaccine. These findings suggest that for vaccines, one size doesn’t fit all -- perhaps men should get larger doses, for example.”