Food for Thought: Oily Fish Found to Protect the Brain From Air Pollution

A new study has found that eating oily fish may help protect aging brains from the detrimental effects of air pollution.

The study, published in the American scientific publication Neurology on Wednesday, looked into the effects of eating fish and shellfish – both of which are rich in omega-3 acids – among older women living in highly polluted areas.

It was already known that omega-3 acids help protect against brain damage caused by neurotoxins like lead and mercury, but the researchers went one step further and tested whether the same was true for fine particulate matter, the neurotoxin found in air pollution.

By triangulating readings of pollution exposure, brain activity, and omega-3 levels, as well as adjusting for age, education, smoking, and other factors that could affect brain shrinkage, researchers were able to ascertain that those women who on average ate two or more servings of fish per week saw positive health effects on the brain.

Of the 1,315 women tested, those found to have the highest levels of omega-3 acids in their blood exhibited the least amount of brain shrinkage and damage.

It's important to note that fried fish did not count towards the participants' omega-3 intake as research has shown that deep-frying damages fatty acids.

So how exactly do omega-3 fatty acids appear to benefit the brain? Through magnetic resonance imaging (MRI), researchers found that those with higher amounts of omega-3 in their blood also exhibited increased volumes of white matter in the brain, indicating a correlation between the two. White matter is composed of nerve fibers and aids neuronal connectivity.

A higher density of white matter was also found in the hippocampus, the part of the brain associated with memory.

In a press release, author of the study Dr. Ka He of New York's Columbia University explained, "Omega-3 fatty acids have been shown to fight inflammation and maintain brain structure in aging brains. They have also been found to reduce brain damage caused by neurotoxins like lead and mercury. So we explored if omega-3 fatty acids have a protective effect against another neurotoxin, the fine particulate matter found in air pollution."

"It's important to note that our study only found an association between brain volume and eating fish. It does not prove that eating fish preserves brain volume," added He. Also, the beneficial effects of eating fish may be compromised by other factors such as environmental toxins.

In a twist of fate, Beijing's seafood supplies were recently decimated in the wake of the second wave of coronavirus, which was traced back to Fengtai District's Xinfadi produce market. While stocks are slowly being replenished, it may be that we have to rely on tinned fish for now to replenish our natural pollution-fighting powers.

READ: Hazy Days: Your Complete Guide to Pollution in Beijing

Image: Engin Akyurt (via UNSPLASH)