Omega-3 fatty acids from fish oil have been found in previous studies to protect the brain from inflammation and also help the brain maintain its shape during the aging process. Researchers at Columbia University have now found omega-3 fatty acids could protect the brain from the damaging effects of air pollution.
The findings of a study of more than 1,300 women with an average age of 70 were published in the journal Neurology. The report explained that women with the lowest levels of omega-3 in their blood had the most brain shrinkage attributed to air pollution.
"Fish are an excellent source of omega-3 fatty acids and easy to add to the diet," said study author Ka He, M.D., Sc.D., of Columbia University in New York. "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."
The study participants completed a questionnaire about diet, physical activity and medical history. None of the women had dementia at the study’s outset.
Researchers calculated the average fish intake of the participants on a weekly basis. This included broiled, baked or canned fish but not fried fish because the deep frying process has been shown to damage omega-3 fatty acids.
The women were given blood tests to determine the amount of omega-3 fatty acids in their blood and then separated into four groups based on the amount. The researchers then used the women’s home addresses to calculate their three-year average exposure to air pollution.
Magnetic resonance imaging (MRI) scans were done of the brains of the participants to measure the white matter, which is where nerve fibers send signals through the brain, as well as the hippocampus, the region associated with memory.
Scientists factored in age, education and other issues that could impact brain shrinkage such as smoking. They found those with the highest levels of omega-3 fatty acids in their blood had the greatest volumes of white matter. They also had the greatest volumes of the hippocampus.
"Our findings suggest that higher levels of omega-3 fatty acids in the blood from fish consumption may preserve brain volume as women age and possibly protect against the potential toxic effects of air pollution," said He. "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. And since separate studies have found some species of fish may contain environmental toxins, it's important to talk to a doctor about what types of fish to eat before adding more fish to your diet."