Fish is an important part of a healthy diet – particularly when it comes to brain health, due to its high concentration of beneficial omega-3 fatty acids. A recent study also found that eating fish once or twice a week may have another brain benefit as people age: protecting critical brain structures from the harmful effects of air pollution.
The Columbia University research focused on a group of more than 1,300 older women living in U.S. cities with high pollution levels. Using blood and magnetic resonance imaging (MRI) tests, the study found that those with low levels of omega-3 fatty acids in their blood had more brain “shrinkage” than women who had the highest levels.
The researchers also used a diet questionnaire to calculate the average amount of fish the women consumed each week, including broiled or baked fish, canned tuna, tuna salad, tuna casserole and non-fried shellfish. (Deep-fried fish was not included because frying damages omega-3 fatty acids.)
Those who ate fish every week consistently had the highest blood levels of omega-3s. They also had consistently greater volumes of both the hippocampus and white matter in their brains.
Even in cities with the highest air pollution – which has been shown to accelerate brain volume loss – women who ate more fish had preserved far more of their brains’ white matter compared to others with lower omega-3 levels.