There’s still no guaranteed way to prevent dementia. But new WHO guidance says a surprisingly large share of dementia risk is linked to factors we may be able to change.
Why it matters
Most people don’t start worrying about dementia at 45.
We worry about mortgages. Children. Careers. Retirement savings. Whether our knees can still handle badminton or pickleball. Brain health feels like something for much later. But dementia prevention may actually begin decades before memory problems appear.
In July 2026, the World Health Organization released updated guidelines saying up to 45% of dementia risk could potentially be prevented or delayed by addressing modifiable risk factors.
That sentence needs to be interpreted carefully. It does not mean 45% of individual dementia cases are guaranteed to disappear if people live perfectly. And it certainly doesn’t mean someone who develops dementia failed to look after themselves.
Age, genetics and other factors outside individual control remain important. What it means is that a substantial proportion of dementia risk at population level is associated with factors that can potentially be modified.
Surprisingly, many aren’t specifically “brain” problems
WHO highlights factors including: physical inactivity, smoking, harmful alcohol use, social isolation, air pollution, high blood pressure, diabetes and high cholesterol. Hearing matters too. WHO says hearing aids may be offered as part of dementia risk-reduction strategies for people with hearing loss. And staying cognitively and socially engaged may also help.
In other words, protecting your brain increasingly looks a lot like protecting the rest of your body.
What about supplements?
This is where things get interesting.
Walk into a pharmacy or scroll through social media and you’ll find plenty of products promising “brain health.” WHO’s updated guideline specifically says it does not recommend vitamins B and E, omega-3 supplements or multivitamin/mineral supplements solely for reducing cognitive decline or dementia risk when someone does not have a diagnosed deficiency.
That’s an important distinction. Taking a supplement to correct an actual nutritional deficiency is one thing. Taking one because the bottle implies it will prevent dementia is another.
So what should someone in their 40s or 50s actually do?
The answer isn’t very glamorous.
Move regularly.
Don’t smoke. Keep blood pressure, cholesterol and diabetes under control.
Eat well. Stay socially connected. Protect and treat your hearing. Keep using your brain and minimise harmful alcohol consumption. None of these offers a guarantee against dementia. But together they shift the odds.
More than 57 million people worldwide currently live with dementia, with nearly 10 million new diagnoses each year, according to WHO. So even modest reductions in population-level risk could have enormous consequences. And perhaps that’s the most useful way to think about brain health.
You don’t suddenly start protecting your brain when you’re 70.
You’re protecting tomorrow’s brain with many of the things you do for today’s heart and body.
ET takeaway: There may never be one magic pill that prevents dementia. But the evidence increasingly suggests that what we do in midlife matters — possibly much more than we once thought.
