I am "peri-menopausal" now almost 3 months since my last cycle and starting to have hot flashes. Is this bad for my brain? I don't think hot flashes are due to lack of estrogen per se, it is believed that they are due to some complex interactions in the hypothalamus, probably having to do with excess FSH and other responses to the low serum estrogen that make the hypothalamus extra sensitive to tiny changes in body temperature. But the brain is not starved for estrogen, because it makes its own estrogen, right? Does anyone know what happens to brain estrogen in menopause?
My understanding is that estrogen helps to play a role in delivering fuel to the brain and an abrupt drop, that can sometimes happen during perimenopause, is what causes the problem. This sets off a cascade of other pathology that can affect our genotype more aggressively. We know that E4 carriers (in a dose dependent fashion) already deal with decreased utilization of cerebral glucose starting in our third decade. Any degree of insulin resistance, that also tends to strike around this same time, also exacerbates this neural fuel shortage. When we add perimenopause to the mix, many E4 women are hit hard. FWIW, I suffered horribly from hot flashes (20+ per day) seemingly overnight when I was transitioning to menopause. BHRT was a lifesaver for me. You might find this paper helpful.
From a mechanistic perspective, estrogen dysregulation during perimenopause significantly affects brain bioenergetics . The brain is dependent upon glucose as the principal metabolic fuel to generate ATP–a system that is partially regulated by estrogen. During perimenopause, estrogenic regulation of cerebral glucose metabolism (CMRglc) falters, inducing a hypometabolic state which is accompanied by deposition of amyloid-beta (Aβ, a hallmark of AD pathology), decreased mitochondrial function, and decline in synaptic plasticity [6–8].