New study shows that the omega-3 fatty acids EPA and DHA from fish oil have different effects on chronic inflammation


BOSTON (Dec 7, 2020 at 9:00 a.m. EST)—The omega-3 fatty acids EPA and DHA have different effects on chronic inflammation, according to the results of a small randomized study, suggesting that each has its own important role in regulating the immune system.

The 34-week study, carried out by researchers at the Jean Mayer USDA Research Center on Human Nutrition for Aging at Tufts University (HNRCA), compared the effects of the two omega-3 fatty acids in a small group of older adults with obesity and chronic mild inflammation. Participants were randomly given either EPA or DHA supplements twice a day. The results are published today in Atherosclerosis.

EPA and DHA, which are abundant in fish and shellfish, have been linked in some studies to a lower risk of heart disease and are believed to reduce inflammation. The results showed that DHA had stronger anti-inflammatory effects than EPA:

  • DHA lowered the genetic expression of four types of pro-inflammatory proteins, while EPA lowered only one type.
  • DHA lowered white blood cell secretion of three types of pro-inflammatory proteins, while EPA lowered only one type.
  • DHA also reduced levels of an anti-inflammatory protein, while EPA didn’t.

However, EPA improved the balance between pro-inflammatory and anti-inflammatory proteins:

  • Once metabolized, EPA produced by-products that were implicated in regulating immune function and acted differently from those derived from DHA.

“The jury quarreled, so to speak, about how the two main components of fish oil work – and whether one is perhaps better than the other. These results suggest that DHA is the stronger of the two markers of inflammation in the body, but that’s not the end of the story, ”he said Stefania Lamon-Fava, a scientist on the cardiovascular nutrition team at the HNRCA.

Lamon-Fava is also Chair of the Department of Biochemical and Molecular Nutrition and Associate Professor at the Gerald J. and Dorothy R. Friedman School of Nutrition Science and Policy in Tufts.

“There is always this balance in our body between pro-inflammatory and anti-inflammatory proteins, and we have found that EPA improves that balance better than DHA. For the prevention of cardiovascular diseases, previous research has shown us that balance is very important, ”explains first author Jisun So, who did this work as part of her dissertation at the Friedman School in the cardiovascular nutrition team of the HNRCA.

According to the Dietary Guidelines 2015-2020 for Americans, Adults should have at least two servings of seafood (4 ounces per serving) weekly. Salmon, cod, sardines, trout, and canned light tuna are good sources of EPA and DHA.

“Our study gives us a snapshot of how EPA and DHA can reduce chronic inflammation and how they each have different effects. Our results provide insight for future research to find out why this is the case and who would benefit from either or both of these healthy fats, ”said Lamon-Fava.


The study was a double-blind study, meaning that neither the participants, the laboratory staff nor the scientists knew which nutritional supplements each received. The 21 participants received EPA or DHA supplements in an order that included supplement-free periods to create a blank board on which the effects of each supplement could be measured. During an introductory phase, participants took dietary supplements that contained only high oleic sunflower oil (similar to olive oil and without omega-3 fatty acids) to provide a basis for comparison.

Authors and Funding

Other authors of the study are Dayong Wu, Alice H. Lichtenstein and Nirupa R. Matthan from the HNRCA; Albert K. Tai of Tufts University Medical School; and Krishna Rao Maddipati from Wayne State University.

This work was supported by the US Department of Agriculture’s National Institute of Food and Agriculture through a grant from the Agriculture and Food Research Initiative and by The Drs. Joan and Peter Cohn Research Fund. All opinions expressed in this post are those of the authors and not the donors. None of the authors disclosed any conflicts of interest.


So, J., Wu, D., Lichtenstein, AH, Tai, AK, Matthan, NR, Maddipati, KR and Lamon-Fava, S. (2020). EPA and DHA modulate the inflammatory response of monocytes differently

Patients with chronic inflammation partially specialized in plasma

Pro-Dissolving Lipid Mediators: A Randomized, Double-Blind, Crossover Study. Arteriosclerosis.


Via the Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University

For four decades, the Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University has been studying the relationship between good nutrition and good health in aging populations. Tufts scientists work with federal agencies to set the nutritional guidelines, dietary recommendations, and other key public guidelines.


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