Alzheimer's Is Twice As Likely In Women As Men — Could This Explain Why?
Women are twice as likely to be diagnosed with Alzheimer's disease as men, even when accounting for the fact that women generally outlive men by about seven years. Researchers are keen to discover why this may be, and one new animal study that examined the effects of stress on the brain may help explain it.
How stress affects the brains of male and female mice
The study, which was conducted by researchers at Washington University School of Medicine in St. Louis and published in the journal Brain, compared the brain activity of male and female rodents when they underwent massive amounts of stress.
The researchers measured the levels of amyloid beta—a key Alzheimer's protein1—in the brains of male and female mice every hour for 22 hours, beginning eight hours before the mice experienced stress. They first measured the levels of stress hormones in the blood and observed that both sexes experienced the same amount of stress. However, they found that their brains' responses to stress varied significantly between the sexes, with the brains of male mice responding quite differently to the stressful situation than female mice.
Even though both the male and female mice found the experience equally stressful, in the females, levels of amyloid beta rose significantly within the first two hours of experiencing the stressful situation. Additionally, its levels remained elevated throughout the monitoring period. In the males, however, researchers observed mostly no change in amyloid beta levels (aside from the 20% of male mice who experienced a very weak, delayed rise in amyloid beta levels).
Essentially, this study pointed to key ways in which male and female brains process stress completely differently, with further research indicating that this difference is due to a cellular stress response pathway in brain cells. Female rodents possess neurons that take up the stress hormone that's linked to increased amyloid beta levels, but male rodents don't possess these neurons and therefore don't take up the stress hormone.
While it's unclear whether this fundamental difference exists—or is as prominent in—humans, the study indicates biological differences between males and females when it comes to stress.
"There's a fundamental biological difference between males and females in how they respond to stress at the cellular level, in both mice and people," John Cirrito, Ph.D., an author of the study and associate professor of neurology, said in a statement. "We don't think that stress is the sole factor driving the sex difference in Alzheimer's disease. There are many other differences between men and women—in hormones, lifestyle, [and] other diseases they have—that undoubtedly contribute in some way. But that stress is driving one aspect of this sex difference I think is very likely."
While this is not the first study linking stress to Alzheimer's disease2, it's unique in that it attempts to find out why women are much more likely to be diagnosed with the disease than men. One shouldn't discount biological differences in reaction to stress as a prominent factor.
How to manage stress
While the results of this animal study may not directly translate to humans, health care practitioners generally acknowledge that stress can wreak havoc on your body, from weakening your immune system3 to increasing your biological age. Therefore, finding ways to manage it is key. Here are some top tips to help you manage your stress levels:
Take a supplement. Certain supplements, such as ashwagandha, cannabidiol oil (CBD), and magnesium, are proven to help your body manage the effects of stress, so you might want to add one to your daily routine. Here are our 14 favorite stress supplements to help you get started.
Consider meditation. Research has shown that meditation helps calm your nervous system and improve your emotional reactions to stressful situations4. Even just a few minutes a day can help.
Exercise. Getting in a quick workout has been proven to release endorphins and help with anxiety and depression5.
Spend time in nature. Spending just 20 minutes in nature6 has been linked to lower stress hormone levels, so think about taking a few outdoor breaks throughout the day.
While reducing your stress levels is vital regardless of your sex, a recent study found that doing so may also help reduce risk factors for Alzheimer's disease, especially among women. Fortunately, there are plenty of simple ways to help reduce stress on a daily basis, such as incorporating supplements or meditation into your routine.
Nikhita Mahtani is an NYC-based freelance journalist covering primarily health and design. She graduated with an M.A in Magazine Journalism from New York University, and loves to debunk popular health myths. Her idea of wellness includes a sweaty spin class, wine with loved ones, and experimenting with new recipes in the kitchen. She's written for GQ, InStyle, Conde Nast Traveler, Food Network, Bon Appetit, and more.