According to a new cross-sectional clinical trial, conducted by researchers at the Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University and published in the journal Atherosclerosis, the two most commonly sought-after omega-3 fatty acids, EPA and DHA, each have a uniquely beneficial role to play when it comes to modulating the inflammatory response.
 
A 34-week double-blind trial enrolled 21 participants who had obesity and chronic low-grade inflammation, who were administered a daily dose of either EPA or DHA, in a sequence following a washout period, to address the impact of each supplement. During a lead-in phase, participants took supplements containing only high-oleic sunflower oil, which contains no omega-3s, to create a basis for comparison.
 
Each of these nutrients, found most abundantly in seafood and shellfish, have been evidenced in clinical trials to lower the risk of heart disease, and it’s believed that the mechanism of action by which they protect the heart is by mitigating excessive inflammation. The results showed that DHA had a stronger effect on inflammation than EPA.
 
DHA lowered the genetic expression of four types of pro-inflammatory proteins, whereas EPA only lowered one type. It also lowered the white blood cell secretion of three types of pro-inflammatory proteins, while EPA only lowered one type. DHA reduced the levels of a protein which has an anti-inflammatory effect, however, while EPA did not.
 
EPA did have a unique attribute believed to be beneficial, though, in that it improved the balance between pro- and anti-inflammatory proteins after being metabolized. EPA produced byproducts that were associated with regulating immune function, and those metabolites worked differently from those derived from DHA.
 
“The jury has been out, so to speak, on how the two major components of fish oil work – and whether one might be better than the other,” Stefania Lamon-Fava, a scientist on the cardiovascular team behind the study said. “These results suggest that DHA is the more powerful of the two markers of inflammation in the body, but that’s not the end of the story. Our study gives us a snapshot of how EPA and DHA may work to reduce chronic inflammation, and how each has distinct effects. Our results provide insight for future research to explore why that is the case and who would benefit from one or both of these healthy fats.”
 
“In our bodies, there is always this balance between pro-inflammatory and anti-inflammatory proteins, and we found EPA was better than DHA at enhancing that balance,” Jisun So, who conducted this study as part of her dissertation, said. “For the prevention of cardiovascular disease, previous research tells us that balance is very important.”