Why More Women Than Men Get Alzheimer's

Surprisingly, the answer was menopause.

My research has shown that menopause changes the female brain in a big way. For some women, it's hot flashes and mood swings and disturbed sleep. For other women, it's actually a higher risk of Alzheimer's. Our studies have shown that it's not just that women live a little bit longer than men, but rather that women develop these Alzheimer's changes in their brains earlier than men, specifically due to menopause.

How is brain health affected by menopause, specifically in terms of hormones like estrogen, which you call the “master regulator” of the female brain?

We think about sex hormones — like estrogen for women and testosterone for men — as chiefly for reproduction. However, these hormones serve a number of functions in the brain that have nothing to do with reproduction, but that have everything to do with brain energy. Both estrogen and testosterone literally push your neurons to burn glucose to make energy.

For women, our estrogen drops in midlife during menopause. That has consequences in the brain because estrogen supports energy metabolism in the brain and is also involved in growth, plasticity, and immunity. Basically, it keeps your brain younger and healthier. So if you lose your estrogen, a lot of things happen inside your brain.

When women experience menopause symptoms like hot flashes, what's going on in the brain?

There are specific brain regions that are very connected to our estrogen levels. The number one brain region is called the hypothalamus, which is in charge of regulating body temperature. So if estrogen doesn't activate the hypothalamus correctly, then the brain cannot regulate body temperature. And that's why we get hot flashes.

Then there's another part of the brain called the brain stem that is in charge of sleep and wake and also stress. If estrogen doesn't activate the brain stem correctly, we can get mood swings, for example, or we have trouble sleeping at night.

Then there's the hippocampus, which is the memory center of the brain. It's also really heavily estrogen-dependent. If estrogen is all over the place in the hippocampus, we may have trouble remembering information. So there's a whole network in the brain that is in trouble as women go through menopause and that creates all these symptoms.

Menopause isn't something women can avoid, but you write how lifestyle choices like diet and exercise, along with hormone replacement therapy, can help. For someone who's reading this and thinking, I'm going through menopause and now I'm worried, what sort of guidance would you give them?

The fact is, science validates these concerns: 20 percent of women going through menopause have no problems whatsoever, but 80 percent of women do. So, number one, it's really important to acknowledge that.

Number two, menopause is something you can't avoid. But the way you experience menopause has something to do with the choices you make in your life on a daily basis. For example, smoking is the number one cause of early menopause in women. A bad diet is also something that's been linked to early menopause in women, especially consumption of refined sugar, refined grains and processed foods.

Exercise is really important as well and has been shown to be incredibly good for your brain. It's linked to a lower risk of Alzheimer's disease and dementia later in life, and much better fertility and ovarian health — which means better outcomes during menopause, like a later age of onset of menopause and also less severe symptoms.

Another big thing is stress reduction. Studies have shown that chronic stress, especially with high cortisol levels, accelerates brain shrinkage in midlife and correlates with poor memory, and much more so for women than for men.

Speaking of stress, women are also more likely to be caregivers than men. Is there a relationship between caregiving and brain health?

Women account for, at the very least, 60 percent of all caregivers, and about two-thirds of all caregivers for Alzheimer's patients specifically. We know that there's a condition called caregiver burden that really severely taxes a caregiver's health. There's some evidence showing that if you're really stressed as a caregiver, you even have a higher chance of Alzheimer's yourself, which is really unfair in so many ways.

I think it's really important as a caregiver to take all the help you can get without feeling bad about it. It's a lesson for women, not just as caregivers but in general. Midlife is such a big turning point in a woman's life. It's a time when we should be taking extra care of ourselves, rather than less.