WHO updates dementia guidance: a new risk factor, supplements to avoid and a hearing loss must

You’re going to want to remember this.

Around the world, more than 57 million people are living with dementia, and nearly 10 million more are diagnosed each year.

While there is currently no cure, research suggests that up to 45% of dementia cases could be prevented or delayed by addressing modifiable health and lifestyle factors.

Now, the World Health Organization (WHO) is updating its guidance on how to do just that, releasing the first major revision to its recommendations for preventing dementia and cognitive decline since 2019.

“We know more today than ever before about what drives dementia risk, and these guidelines translate that knowledge into action,” Dr. Tedros Adhanom Ghebreyesus, WHO director-general, said in a press release.

“Countries now have clear, evidence-based recommendations they can put into practice immediately to protect people’s cognitive health.”

While much of the report builds on advice first issued by the WHO seven years ago, it also highlights several newer strategies that global health experts say may help people protect their cognitive health as they age.

Here are three of the most notable updates — including one common practice the WHO says you may want to rethink.

Breathe cleaner air to protect your brain

One of the biggest changes in the global public health agency’s 2026 guidance centers on a surprising factor that may influence dementia risk: the air people breathe every day.

The WHO now recommends limiting exposure to air pollution as part of a broader strategy to lower the risk of cognitive decline and dementia.

The biggest concern centers around fine particulate matter, particularly tiny particles known as PM2.5. These microscopic pollutants come from a variety of sources, including wildfire smoke, vehicle exhaust, industrial emissions and even some household products.

Because they are so small, PM2.5 particles can slip past the body’s natural defenses and may reach the brain. Researchers believe they can trigger inflammation and oxidative stress — two harmful processes that may contribute to cognitive decline over time.

And this isn’t just a problem for people living in cities covered by smog. The WHO estimates that 99% of the global population is exposed to air pollution levels that exceed its recommended limits.

While eliminating air pollution entirely isn’t realistic, the agency says reducing exposure could still make a difference.

That may include simple changes, such as cooking with cleaner energy sources like electricity or gas instead of wood or charcoal, as well as broader efforts, like supporting policies to curb emissions from cars, factories and other sources.

“In theory, if air pollution was reduced to zero at the population level, it is estimated that about 3% of dementia cases could be prevented,” the report states.

Skip these supplements — unless you actually need them

A healthy, balanced diet remains one of the most widely recommended ways to support brain health. But when it comes to supplements, the WHO says more isn’t necessarily better.

The agency is now urging people without diagnosed nutritional deficiencies not to take certain vitamins and supplements in hopes of preventing cognitive decline and dementia.

The list includes vitamins B and E, omega-3 polyunsaturated fatty acids, and multivitamin or mineral combinations — products often marketed with claims that they support memory, focus and healthy aging.

But the WHO found there isn’t enough scientific evidence showing that these supplements can actually prevent, stop or reverse dementia in people who are not deficient.

In its report, the agency warned that taking unnecessary supplements may carry risks that outweigh any potential benefits.These include the buildup of certain nutrients in the body, which can become harmful over time, as well as possible negative interactions with medications.

Don’t ignore hearing loss

The WHO’s guidance on hearing loss also received a major update.

Worldwide, about one in five people experience some degree of hearing loss, but many cases go undiagnosed.

The consequences go beyond struggling to follow a conversation. Untreated hearing loss has also been associated with an increased risk of cognitive decline and dementia.

While the WHO recommended screening for hearing loss in its 2019 guidelines, the agency now specifically backs providing hearing aids as a way to help reduce dementia risk.

Hearing loss may affect cognitive health in several ways. When the brain has to work harder to process sounds, fewer resources may be available for other thinking tasks. It can also contribute to social isolation, which itself is associated with a higher dementia risk, and may lead to changes in brain structure and function.

But addressing it could have a significant impact.

“In theory, if hearing loss was reduced to zero at the population level, it is estimated that about 7% of dementia cases could be prevented,” the report states.

Beyond these newer recommendations, the WHO’s updated guidance highlights several other strategies that may help protect cognitive function.

The agency places greater emphasis on cognitive training, recommending activities designed to challenge the brain for adults with normal cognition as well as those experiencing mild cognitive impairment.

It also highlights the importance of staying socially connected, pointing to activities like volunteering and maintaining relationships with friends and family as valuable ways to support cognitive health as people age.

The report also reiterates several previously recommended interventions that can lower dementia risk, including getting regular physical activity, reducing alcohol use, quitting smoking, following a healthy diet and managing chronic conditions linked to cognitive decline, such as obesity, diabetes and high blood pressure.