Monday, September 11, 2017

Some interesting new ways to look at menopause

I read an interesting article in New Scientist recently (not a magazine I usually read or have access to) about menopause (not a subject I usually pay much attention to).
Menopause basically marks the end of a woman's ability to bear children. The number of eggs in a woman's ovaries starts to dwindle, and the amount of estrogen (oestrogen) and other related hormones she produces takes a nose-dive. This results in the typical menopause symptoms: hot flushes, tiredness, weight gain, mood swings, reduced sex drive and vaginal dryness.
One other common symptom of menopause, though, is memory and concentration lapses, and it turns out that changes in the brain that occur during this time are similar in many ways to those occurring during the onset of Alzheimer's Disease, something else that predominantly afflicts women. (Contrary to general belief, men are also affected by menopause - usually referred to as the andropause - but it is a much more gradual and undramatic process.)
Recent research has shown that brain cells have lots of estrogen receptors, and a drop in estrogen production can therefore have a significant effect on memory, mood and general brain health. Indeed, it is possible that menopause might kick-start Alzheimer's. Estrogen has a kind of protective function in the brain, as well as fuelling mitochondrial energy reserves. So, when estrogen production suddenly falls during menopause, the brain starts to use the fatty protective myelin sheaths around brain cells for fuel instead of the usual glucose, leading to decreased volumes of white and grey matter and an increase in beta amyloid production, all hallmarks of Alzheimer's. That being the case, research is now being carried out into whether menopause treatments like hormone replacement therapy (which gained a bad reputation after some damning studies in the 2000s, but which is now gradually being rehabilitated, at least when applied in more carefully-controlled and tailored therapies) might also help with Alzheimer's and other forms of dementia.
One other aspect of the menopause the New Scientist article looks at is just why it happens at all. Humans, killer whales and pilot whales are the only animals in nature that live in good health long after their reproductive years are over (most animals continue to reproduce until they die). If the biological imperative of all animals is to pass on its genes to the next generation, what evolutionary purpose might these extra years fill, then? It has been hypothesized that grandmothers in such animals help to bring up and protect children, giving those children a better chance of survival. Also, after a certain age, helping to take care of grandchildren may be a more efficient way of perpetuating the species than trying to conceive new babies. Interesting ideas.

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