And it's not diet or exercise (though those both help, too!)

As many as one in five people 65 and older are currently living with some form of mild cognitive impairment (MCI), which might negatively impact memory, decision-making, or reasoning skills. In 60 to 80% of cases, MCI eventually progresses to Alzheimer's disease, reports the Alzheimer's Association.

Since we're still unsure what causes the vast majority of cognitive impairment diagnosis—nor do we yet have a cure—scientists are rapidly diving into current health databases and conducting their own research to try to determine if there are any factors we can control. Recently, we've learned more about how important many of our daily habits are for potentially preventing dementia (defined as MCI strong enough to alter daily life). In the past few months, researchers have discovered that walking three times per week, not smoking, eating a berry-strong menu and averaging more than six hours of sleep per night can make a serious impact on your brain health throughout your lifespan.

And this week, scientists from NYU Langone Health landed on a new surprising brain-booster. According to their study published August 16 in the journal JAMA Network Open, people who have another person available most or all of the time who can listen show better greater "cognitive resilience," or have a brain that functions about 4 years younger than expected relative to their physical age.

"These four years can be incredibly precious. Too often we think about how to protect our brain health when we're much older, after we've already lost a lot of time decades before to build and sustain brain-healthy habits," lead researcher Joel Salinas, M.D., assistant professor of neurology at NYU Grossman School of Medicine and a member of the Department of Neurology's Center for Cognitive Neurology, tells NYU Langone Health News Hub. "But today, you can ask yourself if you truly have someone available to listen to you in a supportive way, and ask your loved ones the same. Taking that simple action sets the process in motion for you to ultimately have better odds of long-term brain health and the best quality of life you can have."

So as a strong echo to these 13 factors that can lower or raise risk for Alzheimer's disease, social support—including having a friend, family member or even acquaintance to talk to who will truly listen—can help your brain ward off decline.

Flowers in the shape of a brain that have scratches all over it on a designed background
Credit: Getty Images / Hiroshi Watanabe

"We think of cognitive resilience as a buffer to the effects of brain aging and disease. This study adds to growing evidence that people can take steps, either for themselves or the people they care about most, to increase the odds they'll slow down cognitive aging or prevent the development of symptoms of Alzheimer's disease—something that is all the more important given that we still don't have a cure for the disease," Dr. Salinas adds.

The research team used data from the long-running Framingham Heart Study (FHS), and selected 2,171 participants with an average age of 63 to study. They analyzed self-reported details about the availability of supportive social interactions (such as others who will listen, offer advice, show love and affection) as well as sufficient contact with close connections and overall emotional support. The participants' cognitive resilience was measured by "total cerebral brain volume on global cognition, using MRI scans and neuropsychological assessments," according to the research team, which were taken as part of the larger FHS study. People with lower brain volumes tend to experience lower cognitive function, so for this study, the scientists looked at levels of social support, cerebral volume and cognitive performance.

The aspect of social support that was most strongly correlated to higher total cerebral volume and greater cognitive resilience? Having "listener availability," the scientists say.

"While there is still a lot that we don't understand about the specific biological pathways between psychosocial factors like listener availability and brain health, this study gives clues about concrete, biological reasons why we should all seek good listeners and become better listeners ourselves," says Dr. Salinas, who suggests that doctors might want to ask their patients whether they have someone to count on to listen when they need to chat.

"Loneliness is one of the many symptoms of depression, and has other health implications for patients. These kinds of questions about a person's social relationships and feelings of loneliness can tell you a lot about a patient's broader social circumstances, their future health, and how they're really doing outside of the clinic," he adds.

Since this was just one study performed on a specific pool of Americans, we'll need more data to confirm this link to brain health. Still, it can never hurt to tap into your social networks—in real life, via video chat or even phone conversation—when you would like to get something off your chest. And if you don't feel comfortable doing so with a loved one or feel like you might benefit from calling in the pros, the U.S. Centers for Disease Control and Prevention (CDC) has a thorough list of resources for finding a skilled mental health expert tailored to you.