Omega-3 Shows Benefits Against Oxidative Stress

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Lee Swanson Research Update
Omega-3 Shows Benefits Against Oxidative Stress
August 2010
New research suggests that the heart-health benefits of omega-3 fatty acids EPA and DHA may be related to their ability to reduce oxidative stress.

Oxygen-breathing organisms naturally produce reactive oxygen species (ROS), which play an important role in a range of functions, including cell signaling. However, over production of these ROS from smoking, pollution, sunlight, high-intensity exercise, or simply aging, may overwhelm the body’s antioxidant defenses and lead to oxidative stress.

Oxidative stress has been linked to an increased risk of various diseases including Alzheimer’s and cardiovascular disease.

Previous reports had suggested that omega-3 fatty acids may actually increase levels of oxidative stress due to their susceptibility to oxidation. New findings in Free Radical Research indicate that EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid) may actually reduce oxidative stress by reducing levels of a compound called F2-isoprostanes.

Scientists from the University of Western Australia and the University of Montpellier (France) report that daily supplements of four grams of either EPA or DHA for six weeks were associated with reductions of about 20%.

"The data, therefore, suggest omega-3 fatty acids reduce oxidative stress, which is likely related, at least in part, to their anti-inflammatory actions and the expected reduction in leukocyte activity," wrote the authors, led by Dr. Emilie Mas. "These findings give further support for supplementation of the diet with omega-3 fatty acids for cardiovascular risk reduction."

Dr. Mas and her co-workers recruited two sets of people to participate in their study. One group was composed of 59 overweight men with abnormal blood lipid levels, and the other group was composed of type 2 diabetics being treated for high blood pressure. The participants were randomly assigned to receive daily doses of four grams of EPA, DHA or olive oil (placebo) for six weeks.

At the end of the study, the researchers noted that EPA reduced urine levels of F2-isoprostanes by 24% in the overweight men and by 19% in the diabetics, while DHA was associated with a 14% and 23% reduction in these groups, respectively, compared with the olive oil groups.

Furthermore, plasma levels of arachidonic acid (AA) were reduced following both EPA and DHA supplementation, the researchers said.

Dr. Mas and her co-workers note that a previous study in healthy subjects also found benefits, which, combined with their findings, show that omega-3 supplementation may decrease F2-isoprostanes in both healthy and diseased populations.

"Furthermore, the lack of association with changes in fatty acids is noteworthy, in view of the fact that F2-isoprostanes are derived from free radical oxidation of AA, which is significantly reduced following omega-2 fatty acids," the researchers stated. "Therefore, the changes in F2-isoprostanes most likely reflect a true reduction in oxidative stress, rather than resulting from a reduction in the supply of substrate."

"These results show that in humans, EPA and DHA reduce in vivo oxidant stress as measured in human plasma and urine," the researchers concluded.

Free Radical Research Published online ahead of print.