A Dose of Defense?
Omega-3 Supplements Appear Protective against PM Effects
Omega-3 polyunsaturated fatty acids, believed to lessen the risk of
many chronic ailments including arthritis, cancer, heart disease, and
memory loss, may also help protect the heart against certain damaging
effects of air pollution. In a new study by an international team of
researchers, supplementation with omega-3s was associated with
significantly reduced cardiac stress caused by particulate matter less
than 2.5 µm in diameter (PM2.5) in a group of elderly individuals in Mexico City
[
EHP 116:1237-1242; Romieu et al.].
The study is the first to examine the effects of omega-3s on biomarkers
of cellular response to the oxidative stress of air pollution.
Exposure to high levels of particulates
from vehicle exhaust and industrial emissions raises the risk of
hypertension, heart arrhythmia, heart attack, and stroke, with the
elderly being particularly susceptible. Some of the authors had
previously shown both that PM2.5
promotes heart disease by diminishing heart-rate variability and that
omega-3 supplementation could increase heart-rate variability. The
current study was intended to find out how omega-3s achieve their
effects.
The study population of 52 elderly nursing home residents was chronically exposed to high PM2.5 levels;
particulate levels inside the nursing home, where residents spent
nearly all their time, correlated with the smoggy surroundings outside.
For four months starting in 2001, half the participants in the
double-blind study received fish oil supplements at doses typical for
over-the-counter supplement users; the other half received soy oil
supplements.
The research team compared blood samples taken from subjects before
and during supplementation and found that omega-3 use was associated
with diminished oxidative damage in blood cells. The observed
antioxidant effect of omega-3s was much greater in fish oil users than
in soy oil users, a difference the investigators attribute to the
different amounts and types of omega-3s in the two supplement types
(docosahexaenoic acid and eicosapentaenoic acid in fish oil versus
α-linolenic acid in soy oil).
The authors note limitations of their study, such as the small
sample size and limited exposure assessment. However, the finding that
omega-3s appear effective against oxidative stress related to PM2.5 exposure,
with fish oil supplements offering more protection than soy oil
supplements, merits further study in larger populations.
Cynthia Washam
Originally published at http://www.ehponline.org/
