Fact: Two-thirds of Americans with Alzheimer’s are women.

What it does: Your noggin’ calls the shots when it comes to every action the body makes. It locks away memories, keeps your heart pumping, tells your legs to put one foot in front of the other, and lets you know when you ought to drop the dumbbells because your muscles are maxed out. It also stores memories of physical pain to remind you not to make the same mistake again.

It’s biggest threat: The most common form of brain deterioration is Alzheimer’s disease. This slow and fatal disease of the brain affects one in 10 people over the age of 65, however there is growing evidence that it can begin to develop well before symptoms appear, as early as age 40.

Why you’re at risk: Unfortunately, the strongest risk factors—age and heredity—are things you can’t control. And the current stats aren’t promising: having a direct relative (parent or sibling) with Alzheimer’s makes your odds three times greater than someone who does not.

Keep it healthy: Currently there is no cure, but researchers are finding that what’s good for the heart is good for the brain. Studies show cardiovascular conditions such as high blood pressure and stroke can increase the risk of developing Alzheimer’s, so taking care of your ticker is a good place to start. Heart healthy foods, such as walnuts, have been shown to have positive impacts on memory and cognitive function.