In a new study, researchers found older women who eat more than one to two servings a week of baked or broiled fish or shellfish may consume enough omega-3 fatty acids to counteract the effects of air pollution on the brain.
They found that among older women who lived in areas with high levels of air pollution, those who had the lowest levels of omega-3 fatty acids in their blood had more brain shrinkage than women who had the highest levels.
The research was conducted by a team at Columbia University.
Fish are an excellent source of omega-3 fatty acids and easy to add to the diet.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.
In the study, the team explored if omega-3 fatty acids have a protective effect against another neurotoxin, the fine particulate matter found in air pollution.
The study involved 1,315 women with an average age of 70 who did not have dementia at the start of the study.
The researchers used the diet questionnaire to calculate the average amount of fish each woman consumed each week, including broiled or baked fish, canned tuna, tuna salad, tuna casserole and non-fried shellfish.
Fried fish was not included because research has shown deep-frying damages omega-3 fatty acids.
The researchers measured the amount of omega-3 fatty acids in their red blood cells and then divided the women into four groups based on the amount of omega-3 fatty acids in their blood.
They found that women who had the highest levels of omega-3 fatty acids in the blood had greater volumes of white matter than those with the lowest levels.
Those in the highest group had 410 cubic centimeters (cm3) white matter, compared to 403 cm3 for those in the lowest group.
They also found that for each quartile increase in air pollution levels, the average white matter volume was 11.52 cm3 smaller among people with lower levels of omega-3 fatty acids and 0.12 cm3 smaller among those with higher levels.
Women with the highest levels of omega-3 fatty acids in the blood also had greater volumes of the hippocampus, a brain area important for memory functions.
These 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 potentially toxic effects of air pollution.
Previous studies have found some species of fish may contain environmental toxins, and the team says it’s important to talk to a doctor about what types of fish to eat before adding more fish to diet.
One author of the study is Ka He, M.D., Sc.D. from Columbia University in New York.
The study is published in Neurology.
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