Air pollution affects your brain

We know chronic exposure to polluted air—which contains toxic chemicals, heavy metals (such as lead and mercury), particulate matter, and even asbestos fibers—harms your lungs and respiratory tract. This type of impairment may also make you more susceptible to viruses like the flu and increase your risk of dying from the coronavirus!

A new study from Columbia University found that breathing polluted air even causes brain shrinkage. Thankfully, there’s something you can do to counteract that risk.

So, let’s jump right in…

Breathing polluted air shrinks the brain

Previous studies have shown that older women who are exposed to higher levels of air pollution experience greater declines in memory and more brain atrophy (brain wasting) that resembled Alzheimer’s disease (AD) than their counterparts who breathed cleaner air.

So, for this new study, researchers followed more than 1,300 cognitively healthy women, with an average age of 70 years, and asked them about their activity levels, diet, and medical history.

They also administered MRI scans to measure volume of the brain’s hippocampus (which is associated with memory) and white matter (a vast, intertwining system of neural connections that unites different regions of the brain). Some experts consider white matter loss an early marker of AD.

In addition, they took blood samples to determine the amount of omega-3 fatty acids circulating in the blood of each participant. (Omega-3s are the all-important nutrients found in fish, such as salmon and cod.)

Then, the researchers estimated the participants’ exposure to air pollution over a three-year period using home addresses and zip codes.

Those who resided in areas with the greatest air pollution had less white matter and more brain shrinkage. However, having a higher blood level of omega-3s seemed to thwart that process…

In fact, even among the women exposed to polluted air, those with higher omega-3 levels had more brain volume and less shrinkage than women with the lowest levels.

So, researchers concluded that higher levels of omega-3s may help protect the brain against the toxic effects of air pollution. It also seems to help preserve brain matter as women age. And this finding makes perfect sense, as previous studies have shown that omega-3s fight inflammation and help support brain structure in older people. They also seem to reduce brain damage caused by neurotoxins, such as lead and mercury.

Eating fish twice a week isn’t enough

The researchers concluded that eating seafood about twice per week may provide sufficient omega-3 fatty acids to counteract the effects of air pollution on the brain.

But I consider that amount to be a bare minimum—based on the science. The fact is, most Americans don’t eat anywhere near sufficient amounts of seafood. (And many eat no seafood at all!)

So, in my view, most people should also take a high-quality fish oil supplement to maintain optimal blood levels of omega-3s. (You can learn more about how to choose a high-quality fish oil supplement and how much you should take in the June 2018 issue of my Insiders’ Cures newsletter [“Why I’m upping my recommendations for this “controversial” supplement”]. Not yet a subscriber? Become one today!)

Of course, when it comes to picking your fish, I always recommend choosing wild-caught—not farm-raised—fish whenever possible…

For salmon, that means opting for Pacific wild salmon, as almost all the Atlantic salmon is now farm-raised and may contain increased amounts of metals, such as mercury. You can also enjoy wild-caught cod, herring, and mackerel—which are all good sources of omega-3s. (I’ll tell you more about the benefits of cod tomorrow.)

In the end, make sure to get plenty of omega-3s in your diet—whether or not you live in an urban environment. In addition to helping your brain, it will also help your heart and mood!

You should also try to spend a little time each week outside in Nature and in green spaces to improve your respiratory health as well as your general well-being.

To learn much more about the many safe, effective, and science-backed ways to support your cognition as you get older, check out my comprehensive, online learning tool, my Complete Alzheimer’s Fighting Protocol. To learn more, or enroll today, simply click here.


“Hazardous air pollutant exposure as a contributing factor to COVID-19 mortality in the United States.” Environ. Res. Lett. 15 0940a9.

“Erythrocyte omega-3 index, ambient fine particle exposure, and brain aging.”

Neurology, Aug 2020; 95(8): e995-e1007.