When Cold Weather & The Menopause Battle It Out
You may know that (moderate, safe) exposure to the cold allows our body to convert our white and yellow fat into the much healthier brown fat—also called brown adipose tissue, or “BAT” to its friends.
If you didn’t already know that, then well, neither did scientists until about 15 years ago:
The Changed Metabolic World with Human Brown Adipose Tissue: Therapeutic Visions
You can read more about it here:
Cool Temperature Alters Human Fat and Metabolism
This is important, especially because the white fat that gets converted is the kind that makes up most visceral fat—the kind most associated with all-cause mortality:
Visceral Belly Fat & How To Lose It ← this is not the same as your subcutaneous fat, the kind that sits directly under your skin and keeps you warm; this is the fat that goes between your organs and of which we should only have a small amount!
The BAT-pause
It’s been known (since before the above discovery) that BAT production slows considerably as we get older. Not too shocking—after all, many metabolic functions slow as we get older, so why should fat regulation be any different?
But! Rodent studies found that this was tied less to age, but to ovarian function: rats who underwent ovariectomies suffered reduced BAT production, regardless of their age.
Naturally, it’s been difficult to recreate such studies in humans, because it’s difficult to find a large sample of young adults willing to have their ovaries whipped out (or even suppressed chemically) to see how badly their metabolism suffers as a result.
Nor can an observational study (for example, of people who incidentally have ovaries removed due to ovarian cancer) usefully be undertaken, because then the cancer itself and any additional cancer treatments would be confounding factors.
Perimenopausal study to the rescue!
A recent (published last month, at time of writing!) study looked at women around the age of menopause, but specifically in cohorts before and after, measuring BAT metabolism.
By dividing the participants into groups based on age and menopausal status, and dividing the post-menopausal group into “takes HRT” and “no HRT” groups, and dividing the pre-menopausal group into “normal ovarian function” and “ovarian production of estrogen suppressed to mimic slightly early menopause” groups (there’s a drug for that), and then having groups exposed to warm and cold temperatures, and measuring BAT metabolism in all cases, they were able to find…
It is about estrogen, not age!
You can read more about the study here:
“Good” fat metabolism changes tied to estrogen loss, not necessarily to aging, shows study
…and the study itself, here:
Brown adipose tissue metabolism in women is dependent on ovarian status
What does this mean for men?
This means nothing directly for (cis) men, sorry.
But to satisfy your likely curiosity: yes, testosterone does at least moderately suppress BAT metabolism—based on rodent studies, anyway, because again it’s difficult to find enough human volunteers willing to have their testicles removed for science (without there being other confounding variables in play, anyway):
Testosterone reduces metabolic brown fat activity in male mice
So, that’s bad per se, but there isn’t much to be done about it, since the rest of your (addressing our male readers here) metabolism runs on testosterone, as do many of your bodily functions, and you would suffer many unwanted effects without it.
However, as men do typically have notably less body fat in general than women (this is regulated by hormones), the effects of changes in BAT metabolism are rather less pronounced in men (per testosterone level changes) than in women (per estrogen level changes), because there’s less overall fat to convert.
In summary…
While menopausal HRT is not necessarily a silver bullet to all metabolic problems, its BAT-maintaining ability is certainly one more thing in its favor.
See also:
Dr. Jen Gunter | What You Should Have Been Told About The Menopause Beforehand
Take care!
