Alzheimer's disease is the most common cause of dementia, and there is still no cure. That makes a hopeful finding all the more important: a large share of dementia risk is tied to things we can change. Here's what the research says about lowering your risk, and where the evidence is still thin.
What is Alzheimer's disease?
Alzheimer's is a progressive brain disease and the most common form of dementia. It gradually affects memory, thinking and behavior, and over time makes everyday tasks harder. Age and genes play a big part, but they aren't the whole story.
Can you lower your risk of dementia?
To a meaningful degree, yes. The 2024 report of the Lancet Commission on dementia prevention identified 14 modifiable risk factors across a lifetime: less education, hearing loss, high LDL cholesterol, depression, traumatic brain injury, physical inactivity, diabetes, smoking, high blood pressure, obesity, excessive alcohol, social isolation, air pollution and untreated vision loss. Together, the Commission estimated, they account for nearly half of dementia cases worldwide, which means those cases could in theory be prevented or delayed.
No single habit guarantees anything, and many people who do everything right still develop dementia. But the same habits that protect your heart tend to protect your brain too.
Does exercise lower Alzheimer's risk?
The evidence is encouraging. A 2022 meta-analysis of cohort and case-control studies covering more than 250,000 people found that physically active people had about a 20% lower risk of all-cause dementia and a 14% lower risk of Alzheimer's disease, and the link held even over follow-ups of 20 years or more. Walking, cycling, swimming and strength work all count. The best exercise is the one you'll keep doing.
Why does staying social matter?
This one goes out to anyone who secretly loves a canceled plan. In a study of older women, those with larger social networks had a 26% lower risk of developing dementia than women with smaller ones. Social isolation is one of the Lancet Commission's 14 risk factors. Regular calls, shared meals, clubs and volunteering all keep you connected.
What should you eat to protect your brain?
Diet patterns look more important than any single food. In more than 60,000 adults in the UK Biobank, those who followed a Mediterranean-style diet most closely had up to 23% lower dementia risk than those who followed it least, regardless of their genetic risk. That way of eating is built on vegetables, fruit, beans and legumes, whole grains, nuts and seeds, herbs and spices, and olive oil, and it's easy to make fully plant-based. For more, see our tips for eating your way to a healthy mind.
What about omega-3s? DHA is a major structural fat in the brain, and diets rich in omega-3s are part of the Mediterranean pattern. But supplements have not been shown to treat Alzheimer's: in a randomized trial in people with mild to moderate Alzheimer's, 18 months of DHA did not slow cognitive or functional decline. Getting enough omega-3 is still worthwhile for general health, and vegans can get DHA from algae. Learn the difference between ALA, EPA and DHA and how to get vegan omega-3.
Does sleep affect Alzheimer's risk?
Sleep appears to matter for the brain's housekeeping. In a small brain-imaging study, a single night without sleep increased beta-amyloid in parts of the brain, the protein that builds up in Alzheimer's disease. Aim for 7 or more hours a night, and read more on why sleep matters.
What else can you do?
- Know and manage your blood pressure, cholesterol and blood sugar.
- Get your hearing and vision checked, and use hearing aids or glasses if you need them.
- Don't smoke, and keep alcohol moderate.
- Protect your head: wear a helmet for cycling and contact sports.
- Keep learning: new skills, languages, music and puzzles all challenge your brain.
If you or someone close to you is noticing changes in memory or thinking, talk to a doctor. Early assessment helps rule out treatable causes and gives you more options.
