Omega-3 by eating fish can protect our brains from the toxic effects of air pollution


Grilled salmon

According to a new study published on July 15, 2020, older women who eat more than one or two servings a week of baked or grilled fish or shellfish can consume enough omega-3 fatty acids to counteract the effects of contamination. of air in the brain. , online edition of Neurology®, the medical journal of the American Academy of Neurology.

The researchers found that among older women living in areas with high levels of air pollution, those with the lowest levels of omega-3 fatty acids in their blood had more brain contraction than women with the highest levels.

“Fish is an excellent source of omega-3 fatty acids and easy to add to the diet,” said study author Ka He, MD, Sc.D. of University of Colombia 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 such as lead and mercury. So we explore whether omega-3 fatty acids have a protective effect against another neurotoxin, the fine particles 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 women completed questionnaires about diet, physical activity, and medical history.

The researchers used the diet questionnaire to calculate the average amount of fish each woman consumed each week, including roasted or baked fish, canned tuna, tuna salad, tuna stew, and non-fried seafood. Fried fish was not included because research has shown that frying damages omega-3 fatty acids.

Participants received blood tests. 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.

The researchers used the women’s homes to determine their three-year average exposure to air pollution. The participants then underwent brain scans with magnetic resonance imaging (MRI) to measure various areas of the brain, including white matter, which is made up of nerve fibers that send signals to the entire brain and the hippocampus, the part of the brain. associated with memory.

After adjusting for age, education, smoking, and other factors that could affect brain contraction, the researchers found that women who had the highest levels of omega-3 fatty acids in their blood had higher volumes of white matter than those with the lower levels. Those in the highest group had 410 cubic centimeters (cm3) of white matter, compared to 403 cm3 for those in the lowest group. The researchers 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 people with higher levels.

Women with the highest levels of omega-3 fatty acids in their blood also had higher hippocampal volumes.

“Our results 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,” she said. I have. “It is important to note that our study only found an association between brain volume and fish consumption. It doesn’t prove that eating fish preserves brain volume. And since separate studies have found that 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. “

A limitation of the study was that most of the participants were older white women, so the results cannot be generalized to others. Furthermore, the researchers were only able to examine air pollution exposures in adulthood, not early or intermediate exposures, so future studies should look at air pollution exposures throughout a person’s life. .

###

The study was funded by the National Institutes of Health.