Research shows up to 45 percent of dementia cases may be preventable. Whatever age you are, here’s what scientists say about how to protect your brain — starting now.
Brain health isn’t made or broken in a single decade; science shows it’s something built across a lifetime. Age and genetics remain the biggest risk factors for dementia, but decades of data show that how we live — and how early we start protecting our health — can make a difference.
The Lancet Commission on Dementia Prevention, Intervention and Care estimates that up to 45 percent of cases worldwide are linked to factors that can be changed: hearing loss, high blood pressure, diabetes, smoking, inactivity, depression, and isolation among them.
A Yale study found that young people are increasingly reporting serious difficulty with memory and focus. The share of adults who said they had “serious difficulty” with memory or concentration grew from 5.3 percent to 7.4 percent over the past decade — nearly doubling among people aged 18 to 39.
Additionally, chronic conditions like diabetes, hypertension, and heart disease were linked to higher reports of cognitive trouble.These findings highlight the importance of maintaining brain health and protecting against dementia.
In your 30s and 40s: Build brain reserve early
Alzheimer’s and dementia specialists interviewed by Being Patient repeat a consistent message: brain health is lifelong. Below, research-backed ways to reduce risk — and how the focus shifts as we age.
Stay physically active
Exercise increases blood flow to the brain, stimulates growth factors that support neurons, and reduces vascular risk. People who maintain regular aerobic activity in midlife show slower cognitive aging decades later.
New York University neuroscientist Wendy Suzuki told Being Patient that regular exercise doesn’t just strengthen the body – it also benefits the brain. As people become more physically fit, she said, levels of neurochemicals such as dopamine and serotonin rise.
“Those growth factors are actually stimulating the birth of brand-new brain cells in a key brain area, the hippocampus,” she said. “It’s critical for long-term memory…You are literally re-sculpting your brain with exercise.”
Science-backed to-do: Aim for at least 150 minutes a week of moderate movement — brisk walking, cycling, dancing, swimming — and add resistance training twice a week.
Protect hearing before it declines
Midlife hearing loss is one of the largest modifiable dementia risk factors identified to date. Even mild loss, left untreated, doubles long-term dementia risk. Conversely, adults who use hearing aids have about half the risk of cognitive decline as those who don’t.
Science-backed to-do: Get a hearing test by 40 and every few years after. Modern hearing devices are discrete, often covered by insurance, and help preserve brain pathways tied to sound and language.
Prioritize sleep
Sleep is the brain’s “washing machine.” During deep sleep, cerebrospinal fluid flushes away waste proteins including amyloid and tau — both key hallmarks of Alzheimer’s. Studies show adults sleeping fewer than six hours a night in midlife face a higher risk of dementia later on.
Researchers say that slow-wave, or deep sleep is when this rinse cycle does its work, clearing out toxic proteins, like beta-amyloid, before they build up. University of Pennsylvania neuroscientist Li-Feng Xiang-Jie told Being Patient, without enough slow-wave sleep, “the garbage can keep accumulating,” making it harder for the brain to stay healthy over time.
Science-backed to-do: Keep a consistent bedtime, limit late-night screen light, and talk with your doctor if snoring or insomnia persist.
Manage stress and mood
Chronic stress and untreated depression change hormone levels, increase inflammation, and can damage the hippocampus — the brain’s memory center.
Treating depression, engaging in therapy, and practicing mindfulness or exercise all reduce risk.
A large Swedish study of more than 1.3 million adults, suggests that people with a history of chronic stress or depression are about twice as likely to be diagnosed with mild cognitive impairment or Alzheimer’s, with risk rising to four times as likely when both are present. Scientists think stress hormones like cortisol which can result in increased brain inflammation, and disturbed sleep help explain this link between mood and memory.
“The prefrontal cortex, which is involved in top-down regulation and higher order cognitive functioning, tends to not do very well under stress, so you see less activity there,” said Yale neuroscientist Elizabeth Goldfarb.
Science-backed to-do: Prioritize mental health care as preventive medicine, not crisis response.
Consider your diet
In clinical trials, participants who followed the MIND diet — short for “Mediterranean-DASH Intervention for Neurodegenerative Delay” — had slower cognitive decline and fewer Alzheimer’s diagnoses.
Neurologist and Alzheimer’s expert Dr. Marwan Sabbagh told Being Patient, “We all want to engage in wellness and brain health. What’s the quickest thing you can do to alter that? It’s your diet.”
In your 50s and 60s: Protect the brain by protecting the body
Control blood pressure and heart health
Hypertension and diabetes are strongly tied to vascular dementia and Alzheimer’s disease. In one long-term study, controlling blood pressure in midlife lowered dementia risk by 15 percent.
Dr. JoAnn Manson, a Harvard professor and chief of the division of preventive medicine at Brigham and Women’s Hospital, commented that the study “not only adds to the evidence that controlling blood pressure reduces the risk of dementia but also demonstrates that these non-physician community healthcare providers can deliver important risk-reduction interventions.”
Science-backed to-do: Keep blood pressure under 120/80 mm Hg, monitor blood sugar and cholesterol, and don’t smoke.
Stay current on vaccines
Adults who get flu, shingles, or Tdap vaccines are less likely to be diagnosed with Alzheimer’s later in life, according to multiple large studies. Research suggests vaccines may reduce inflammation or help immune cells clear toxic proteins.
Dr. Avram Bukhbinder said the reduced risk of Alzheimer’s disease associated with vaccines may be due to a combination of factors.
“Vaccines may change how the immune system responds to the build-up of toxic proteins that contribute to Alzheimer’s disease, such as by enhancing the efficiency of immune cells at clearing the toxic proteins or by ‘honing’ the immune response to these proteins so that ‘collateral damage’ to nearby healthy brain cells is decreased,” he said. “Of course, these vaccines protect against infections like shingles, which can contribute to neuroinflammation.”
Science-backed to-do: Keep up with annual flu shots and shingles vaccination around age 50; ask your clinician about RSV or pneumococcal vaccines, which may offer additional protection.
Eat for brain health
The MIND diet emphasizes leafy greens, whole grains, berries, fish, nuts, and olive oil.
“Inflammation is strongly implicated in the development of neurodegenerative diseases like Alzheimer’s, and evidence suggests anti-inflammatory diets might help protect the brain,” public health researchers Lauren Ball and Emily Burch wrote.
In a 2015 study of 923 adults in their late 50s to late 90s, researchers found that people who followed the MIND diet very closely had up to a 53 percent lower risk of developing Alzheimer’s.
Science-backed to-do: Two servings of leafy greens and one serving of berries a day are associated with better cognitive scores.
Keep learning and stay socially active
Cognitive and social engagement strengthen neural connections, creating “cognitive reserve” that helps the brain compensate for age-related changes. In large population studies, loneliness has been as harmful to brain health as obesity or smoking.
Science-backed to-do: Join a class, volunteer, or pick up a new hobby. Even one group activity per week can lower dementia risk.
In retirement: Stay engaged, treat health issues promptly
Super-agers – people 80 or older who perform well in memory tests – tend to stay socially, mentally, and physically active, suggesting that connection, purpose, and activity could help protect cognition in later life.
“In our study, we observed that super agers do not appear to accumulate aging-associated proteins, such as tau and amyloid pathology,” Merle Hoenig, postdoctoral fellow at University Hospital Cologne in Germany, said in a news release.
Stay on top of new hearing or vision issues
Hearing and vision often decline faster after 65, but both are treatable. In separate studies, cataract surgery and consistent hearing aid use were linked to slower cognitive decline.
Science-backed to-do: Schedule annual hearing and vision checks. Treating sensory loss can preserve orientation, safety, and cognition.
Keep up with being physically and mentally active
Even moderate exercise in later life can improve blood flow and support brain volume. Cognitive activity — reading, puzzles, language learning — helps maintain mental sharpness.
Science-backed to-do: Combine walking with conversation or learning — activities that engage body and mind together show the greatest benefits.
Manage chronic conditions
Science-backed to-do: Follow up regularly on labs and medications, and discuss any new memory or mood changes with your clinician.
Find your community
Older adults who report strong social ties live longer and maintain cognition longer. Conversely, isolation can accelerate decline.
Science-backed to-do: Plan standing weekly calls or outings. Regular contact builds routine, accountability, and cognitive engagement.
Talk to your doctor about new screening tools
Advances in diagnostics — from blood-based biomarker panels to retinal imaging and amyloid or tau PET scans — are expanding early detection. These tools can help doctors rule dementia in or out and guide access to emerging therapies.
Experts generally agree that Alzheimer’s biomarker testing isn’t recommended for people who don’t have symptoms. Sorbonne University neurologist Nicholas Villain told Being Patient, “Most asymptomatic individuals with positive biomarkers will never develop symptoms in their lifetime.”
Many people assume these tests can tell them whether they’ll develop Alzheimer’s, but they only measure biomarker levels – and scientists still don’t fully understand what those levels mean in otherwise healthy people.
Science-backed to-do: Ask your doctor which tests are covered and whether they’re appropriate given your age and symptoms.
Brain health through the decades
There is no guaranteed way to prevent dementia, but research consistently shows that everyday choices — controlling blood pressure, staying active, protecting hearing, eating well, sleeping deeply, connecting socially, and treating health issues early — all add up.