While many people in their 40s are aware of Alzheimer’s disease, it probably doesn’t feel like an immediate threat. That makes sense, because most people with the condition don’t show symptoms until they’ve passed their 65th birthday, according to the National Institute on Aging (NIA).

If Alzheimer’s runs in your family, though, your risk might be on your mind well before your sixth or seventh decade.

There’s no proven way of absolutely preventing Alzheimer’s. But there are steps you can take—especially when you’re younger—to help keep your brain sharp for years to come.

“Making healthy choices when you’re younger is like investing in a 401K,” says Allison B. Reiss, MD, an associate professor in the Departments of Medicine and Foundations of Medicine at NYU Grossman Long Island School of Medicine and a member of the Alzheimer’s Foundation of America Medical, Scientific & Memory Screening Advisory Board. “The work you do now builds a reserve that will pay dividends later.”

The ideal time to start that work is in your 40s. That’s because the first protein of Alzheimer’s disease, called an amyloid, can begin to develop in the brain around this time, per the National Library of Medicine. While the presence of this protein doesn’t mean someone will definitely be diagnosed with Alzheimer’s, it does mean their risk is higher, says Nathaniel Chin, MD, medical director of the Wisconsin Alzheimer’s Disease Research Center and a UW Health geriatrician.

“This tells me, as a memory care geriatric physician and scientist in the field, that reducing risk for Alzheimer’s disease—and all thinking changes—should start in someone’s 40s,” he says. “We have decades to reduce our risk, and it is never too late to start.”

Below, learn seven healthy habits you can start in your 40s to support your brain health now and in the years to come.