Does eating fish protect our brains from air pollution?

Date:
July 15, 2020
Source:
American Academy of Neurology
Summary:
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,
according to a new study.



FULL STORY ========================================================================== 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, according to a
new study published in the July 15, 2020, online issue of Neurology(R),
the medical journal of the American Academy of Neurology.


========================================================================== Researchers 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.

"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 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.

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.

Participants were given blood tests. 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.

Researchers used the women's home addresses to determine their three-year average exposure to air pollution. Participants then had brain scans
with magnetic resonance imaging (MRI) to measure various areas of the
brain including white matter, which is composed of nerve fibers that
send signals throughout the 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 shrinkage, researchers 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. 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 those with higher levels.

Women with the highest levels of omega-3 fatty acids in the blood also
had greater 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." A limitation of the study was that most participants were
older white women, so the results cannot be generalized to others. Also, researchers were only able to examine exposures to later-life air
pollution, not early or mid-life exposures, so future studies should
look at exposures to air pollution across a person's lifespan.

The study was funded by the National Institutes of Health.


========================================================================== Story Source: Materials provided by American_Academy_of_Neurology. Note: Content may be edited for style and length.


========================================================================== Journal Reference:
1. Cheng Chen, View ORCID ProfilePengcheng Xun, View ORCID ProfileJoel
D.

Kaufman, Kathleen M. Hayden, Mark A. Espeland, Eric A. Whitsel,
Marc L.

Serre, William Vizuete, Tonya Orchard, William S. Harris, Xinhui
Wang, Helena C. Chui, Jiu-Chiuan Chen, Ka He. Erythrocyte omega-3
index, ambient fine particle exposure and brain aging. Neurology,
2020 DOI: 10.1212/WNL.0000000000010074 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2020/07/200715163555.htm

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