I read the book "Estrogen Matters" and highly recommend it. Basically, it says your whole body needs estrogen: bones, brain, heart, and without it you end up with heard disease, osteoporosis - which can lead to early death after breaking a hip, and dementia. For me, I just did a Dutch test and am waiting results to get a custom hormone plan to balance the estrogen I have with testosterone/progesterone. I had terrible side effects with my short term memory, fatigue, and dryness internally, which caused me to search for another solution. I'm 59 and still working and my brain was failing so badly it was awful. My practioner is also fine with my cholestrol levels slightly elevated as the brain needs it to avoid dementia. So much for the mainstream medical system's advice. Only time will tell, but my Mom died of dementia so I'm doing what I can to prevent it.