Dementia is a condition that affects the brain, often making it harder for people to remember things, think clearly, or behave as they normally would. It mostly affects older adults, but younger people can get it too.
While scientists know that age is a major factor, they’re still learning about other things that might increase the risk of dementia. One surprising factor? Air pollution.
A new study from Sweden has found that tiny particles in the air we breathe—especially in cities—may be linked to a higher chance of developing dementia. Even more interesting, the study also suggests that certain nutrients in our body, which come from food or are made inside our cells, may be involved in this process too.
Let’s break it down.
The researchers were interested in PM2.5, which is a fancy name for very tiny pieces of dust and pollution in the air. These particles are so small we can’t see them, but they can still get into our lungs—and possibly even our brains. PM2.5 often comes from things like car exhaust and smoke from factories.
The scientists also looked at two important substances in the body. These substances, which we’ll call “body helpers,” are linked to brain health. One of them comes from foods like meat, fish, dairy, beans, and eggs. It helps the brain function properly. The other helper is made inside our cells and can be changed into the first one with the help of vitamins like B12 and folate.
The study followed more than 2,500 older adults living in central Stockholm for up to 12 years. During that time, 376 of them developed dementia. The researchers collected information about their diet, lifestyle, exercise, blood test results, and how much pollution they were exposed to where they lived.
They discovered that people who developed dementia were exposed to slightly higher levels of PM2.5. These same people also had higher levels of one of the “body helpers” and lower levels of the other.
After adjusting for other factors like age, smoking, education, and gender, the scientists found that just a small increase in PM2.5 levels was linked to a 70% higher risk of developing dementia.
Even more surprisingly, about half of that increased risk seemed to be explained by the levels of the two body helpers. In other words, it’s possible that air pollution and these nutrients are somehow working together in the body to increase the risk of brain decline.
Of course, this is just one study. It doesn’t prove that pollution causes dementia, or that changing your diet will prevent it. But it does suggest there’s a link worth exploring.
Scientists believe that pollution may hurt the brain by causing inflammation, damaging blood vessels, or disrupting important chemical processes in the body. And because nutrients like those found in meat, fish, and eggs support brain health, having the right balance of them might help protect the brain from damage—possibly even damage caused by pollution.
So, what can we do?
For now, the researchers say we need more studies to understand how air pollution, diet, and brain health are connected. But one thing is clear: clean air is important not just for our lungs, but also for our brains. And eating a balanced diet that includes brain-healthy nutrients may also play a role in keeping our minds sharp as we age.
This study, published in the journal Neurology, reminds us that small things—like what we eat and the air we breathe—could have a big impact on brain health in the long run.
If you care about brain health, please read studies about inflammation that may actually slow down cognitive decline in older people, and low vitamin D may speed up cognitive decline.
For more information about brain health, please see recent studies about common exercises that could protect against cognitive decline, and results showing that this MIND diet may protect your cognitive function, prevent dementia.
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