Why Women Have a Higher Alzheimer’s Risk, According to Experts

When it comes to Alzheimer’s, the degenerative brain disease that has no cure, inequity is the name of the game: Nearly two-thirds of patients diagnosed with Alzheimer’s are women, and Black Americans are twice as likely as non-Hispanic whites to develop Alzheimer’s.

The sobering fact is that by the time we reach age 65, our lifetime risk of developing the disease sits at 1 in 5, and one large study estimates that by 2050, as many as 9 million women will have Alzheimer’s disease.

Roberta Diaz Brinton, Ph.D., the director of the Center for Innovation in Brain Science at the University of Arizona, noticed this alarming trend three decades ago and has been looking for answers ever since. She says the “reasons” for this discrepancy that kept cropping up didn’t make sense and were downright infuriating.

“I kept hearing over and over that it was because women live longer than men,” Brinton says. “But we only live about four and a half years longer. That does not explain our twofold greater lifetime risk.”

Here’s what the research tells us about why women may have a higher risk for Alzheimer’s than men do, plus expert-backed tips to help support brain health and healthy aging.

Meet the experts: Roberta Diaz Brinton, Ph.D., the director of the Center for Innovation in Brain Science at the University of Arizona; Jill Goldstein, M.D., a professor of psychiatry and medicine at Harvard Medical School and executive director of the Innovation Center on Sex Differences in Medicine at Mass General Hospital; Lisa Mosconi, Ph.D., director of the Weill Cornell Women’s Brain Initiative (WBI) and author of The XX Brain; Cynthia Munro, Ph.D., an associate professor of psychiatry and behavioral sciences at Johns Hopkins University; Jessica Caldwell, Ph.D., a neuropsychologist at the Wisconsin Alzheimer’s Institute.

Lots of factors could be playing a role in why women have a greater risk for developing Alzheimer’s than men do, and researchers like Brinton have spent years combing the data to try to untangle an answer.

For instance, women are more likely than men to develop certain types of brain tumors, nearly twice as likely to deal with depression, three times as likely to get headaches, and more likely to have a stroke and develop an autoimmune disorder that affects the brain (like multiple sclerosis) than men are.

So what gives? Research has shed some light on why women’s brains appear to be more vulnerable to certain diseases than men’s brains. “Sex differences in our biologies—different chromosomes and hormones, for example—affect every chronic disease,” says Jill Goldstein, M.D., a professor of psychiatry and medicine at Harvard Medical School and executive director of the Innovation Center on Sex Differences in Medicine at Mass General Hospital.

An interesting—and completely logical—theory started to take form: “We know that Alzheimer’s disease can take about 20 years to develop prior to a diagnosis, and that the average age of an Alzheimer’s diagnosis is about 72 to 75,” says Brinton. “When you do the math, you can see that when you subtract 20 from that average age of an Alzheimer’s diagnosis, you run into the average age of menopause, which is 51.”

For the female brain, estrogen is the master regulator of energy production, keeping brain cells healthy and active as well as fostering brain activity in regions responsible for memory, attention, and planning.

“We know that estrogen encourages the formation of new connections between brain cells, which makes the brain more resilient and adaptable, and it’s also a neuroprotective hormone that shields brain cells from harm,” explains Lisa Mosconi, Ph.D., director of the Weill Cornell Women’s Brain Initiative (WBI) and author of The XX Brain.

Estrogen dips and surges throughout the month and throughout a woman’s lifetime before drastically plummeting in the years leading up to menopause; the shifting hormones also speed up aging by weakening our neurons and making our brains more vulnerable to disease, Mosconi adds. For example, when Mosconi looked at brain scans of perimenopausal and postmenopausal women, she found 30% reduced brain energy levels; interestingly, men of the same age showed minimal brain changes or none.

“The aging brain is dynamic—it’s not this linear decline that most of us fear,” adds Brinton. “When you know the transitions the female brain experiences that may contribute to disease, you can make yours more resilient.”

How estrogen aids in the brain’s ability to metabolize glucose may also help explain these findings. “In both men and women, the brain consumes quite a bit of glucose—its primary source of fuel,” says Brinton. “But in women, estrogen regulates up to 25% of this glucose metabolism.”

Any condition that limits the brain’s ability to take up glucose from the blood vessels or convert that glucose into energy will impact brain function, Brinton says—which could help explain why women often deal with brain fog and memory lapses when estrogen drops during perimenopause.

Yet something even more alarming starts to happen when having less estrogen slows down your brain’s glucose metabolism: Your brain sends out a starvation response.

“Over the long haul, the brain doesn’t like not getting enough glucose—and it will actually start to ‘eat’ its own white matter for energy,” adds Brinton. (White matter provides essential connectivity, uniting different brain regions into networks that perform various tasks.)

For women with a predisposition to Alzheimer’s, research shows that there also tends to be an increased risk of developing Alzheimer’s amyloid plaques during menopause. (To be clear, not all women develop Alzheimer’s plaques, and not all women with the plaques develop dementia. Researchers are working to better understand this risk.)

And, of course, we can’t talk about midlife women’s health without discussing stress. As it turns out, men’s and women’s brains respond to stress differently, says Cynthia Munro, Ph.D., an associate professor of psychiatry and behavioral sciences at Johns Hopkins University.

Research has found that chronic stress can lead to brain shrinkage and reduced memory performance in people in their 40s and 50s—but it also found that this change was more severe in women. Other studies have shown that men may be biologically better able than women to adapt their brain responses to chronic stress, adds Jessica Caldwell, Ph.D., a neuropsychologist at the Wisconsin Alzheimer’s Institute.

“When stress is chronic and our bodies are telling our brains that we’re continuously in fight-or-flight mode, and that’s really bad for the hippocampus, which is responsible for memory,” Caldwell says.

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The hippocampus region of the brain is loaded with stress hormone receptors (a.k.a. glucocorticoid receptors), which makes it particularly sensitive to stress, explains Caldwell. When the brain is overwhelmed with cortisol, it tries to recalibrate by reducing the amount of the stress signal it listens to, and those glucocorticoid receptors may start to disappear as a result, further deranging the brain’s response to stress—when stress is severe and unrelenting, the ability to respond to future stressors in a healthy way also becomes impaired.

“From our mid-30s to our mid-40s, women are in the work/life/caring-for-children-and-elders/juggling-everything years—and that happens to be when perimenopause is sending estrogen levels down as well,” says Caldwell. This may prevent new brain cells from growing and may even kill brain cells in the hippocampus—a perfect storm seen in women, but not men.

Neuroscientists and doctors say that the earlier you start taking brain-health-boosting steps, the better. In fact, research estimates that more than a third of all Alzheimer’s cases could be prevented if people make changes in how they live their daily lives. The habits below can help preserve and improve brain health and support healthy aging:

Eat a Healthy, Balanced Diet

Multiple studies have shown that a Mediterranean-style diet (full of fruits and veggies, whole grains, nuts and seeds, lean protein like poultry and fish, plant-based proteins like lentils and beans, and healthy fats such as olive oil) is best for your brain, says Mosconi; her research found that brains of 50-year-old women following this diet looked five years younger than those of same-age women who ate a typical meat-heavy Western diet. The plant-based foods in this style of eating are also rich in phytoestrogens, which act like mild estrogen in the body.

It’s also important to get enough fiber. “Fiber influences levels of sex hormone binding globulin [SHBG], which greatly impacts estrogen,” says Mosconi. “Fibrous veggies are a great way to get your brain the glucose it needs, because fiber stabilizes your blood sugar, which allows the glucose to reach your brain.” Try to find fun ways to add more fiber to meals, such as sprinkling nuts on your ice cream!

Move Your Body

Exercise is one of the strongest preventive tools against Alzheimer’s disease for everyone, research shows, but it seems to be especially important for women: In females younger than 65, physical activity is associated with a 30% lower risk of Alzheimer’s compared with those who are sedentary, and women ages 65 to 70 who exercise see a 20% risk reduction, studies show.

Aside from keeping up with a regular workout routine that includes cardio and strength training, try to sneak in more movement throughout your day—this could mean walking up the stairs rather than taking the elevator, getting in a few extra walks on a nice day, or doing a few lunges as you watch TV. “Even little bouts of lower-intensity movement throughout the day will get your heart rate up and increase blood flow to your brain, which helps to keep it healthy,” Brinton says.

Focus on Getting Good-Quality Sleep

Any midlife woman who stares at the ceiling while her male partner starts snoring as soon as his head hits the pillow will relate to the fact that research shows women have a harder time falling asleep—and staying asleep—than men do. But sleep is what Brinton calls the great brain elixir. “As you get older, you have to build in additional repair and recovery time, which happens while you sleep,” she says.

Set up your room for sleep: Turn off the TV, put down your phone, and stash your laptop away at least an hour before bed; establish a relaxing bedtime routine; and make sure your bedroom is dark, quiet, and cool.

Master Stress Relief Tactics

Female neuroscientists have started to study the concept of “cognitive load” (the amount of mental gymnastics most women do on a daily basis to keep all the balls in the air) and its impact on our brains.

“Having some mental load is a good thing,” says Caldwell, but when this added responsibility gets overwhelming, “you’ve got a potentially chronic stressor that’s really bad for your brain.” Be honest about what you can juggle—and what feels like too much. Then take some things off your list.

Consider Hormone Therapy

Rather than brushing off little memory blips and brain fog as just an annoying part of perimenopause that you have to live with, think of them as clues that estrogen changes are happening in your brain, says Brinton. “These are signs that you have a window of opportunity to implement strategies that can prevent risks.”

One of these strategies may be hormone replacement therapy (HRT). “Our research shows that if hormone therapy is prescribed when women have menopausal symptoms, it can reduce the risk of developing Alzheimer’s,” says Brinton. “When HRT is introduced after menopause, when the brain’s estrogen response system has already been dismantled, HRT is of no benefit.”