It’s always been obvious that inhaling air pollution can hurt your heart and lungs. But now researchers are catching on to the fact that the brain and nervous system can be harmed, too.
And the damage can often start with your sense of smell.
According to a study by researchers at the University of Montana along with scientists in Mexico, the air pollution hanging over densely populated cities can quickly damage the nerves in our nasal passages that help us detect odors.
If the health threat from the pollution stopped there, that would be bad enough. But it doesn’t.
There is also strong evidence now that the same pollution leads to neural problems in the brain which can cause Alzheimer’s disease, Parkinson’s disease, and other cognitive issues.1
These researchers found that when we inhale tiny pollutant particles, they can collect along the nerves responsible for detecting odors and affect what’s called the olfactory bulb – the part of the brain just above the nose where this sensory data accumulates.
The result: Your sense of smell suffers. And the damage from the pollution particles may compromise the blood-brain barrier, allowing toxins to enter the brain and cause serious consequences for your neurons.
Autopsies Show Young Brains Already Have Damage
In another study, when the researchers examined autopsy records of more than 200 residents of heavily polluted Mexico City who were aged 11 months to 40 years when they died, they found signs that the pollutants had set off brain inflammation and other damage that increases the risk for Alzheimer’s disease.
They even found this type of brain damage in a baby less than a year old!
“Alzheimer’s disease hallmarks start in childhood in polluted environments, and we must implement effective preventative measures early,” warns researcher Lilian Calderón-Garcidueñas, a toxicologist affiliated with the University of Montana.
The scientists point out that tiny nanoparticles in pollution are small enough to get to any part of the body – entering via the lungs, the nose and the digestive tract.
Other difficulties linked to air pollution include:
Strokes and brain shrinkage: Research demonstrates that even if you live in a rural area, a little bit of air pollution goes a long way toward increasing your chance of mini-strokes that damage neurons. Along with that, a study of residents of rural areas found that just slight increases in pollution can significantly speed a reduction in brain size as you age. In this research, living near a much-traveled road was found to cause significant brain harm.2
Destruction of the brain’s white matter: Tests in California show that pollutants in the air can reduce the brain’s neural connections (its white matter) that are responsible for linking different brain areas.3 The California researchers point out that loss of white matter can “slow cognitive processing speed.” This means a worse memory and problems remembering things.
Of course, to limit your exposure to air pollution, you should avoid living right next to a highway. And try to avoid exercising in heavily polluted areas. Easier said than done, I realize.
Researchers also believe that eating plenty of fruits and vegetables and supplementing with antioxidant nutrients like vitamin C and E can help too.
Interestingly, the researcher Lilian Calderón-Garcidueñas points out that the air in Mexico City is so dirty that it is even very common for dogs living there to get Alzheimer’s disease. Doing autopsies on their brains was one of the first clues she had about the danger air pollution poses to the brain.4
It’s a warning we should all heed.