Cyber Monday Sale: Save 30% or more on all our guides and exclusive bundle offers. Learn more

The Nutrition Examination Research Digest (NERD) aims to provide rigorous, unbiased analysis of the latest and most important nutrition and supplementation studies. Click here to subscribe or login if already a subscriber .

In this article

Fish oil showdown: anti-inflammatory effects of EPA vs. DHA

Chronic inflammation is a driver of many health conditions, and plays a key role in heart disease. Fish oil is a popular supplement partly due to its potential anti-inflammatory actions. But which omega-3 has a greater impact, EPA or DHA?

Study under review: Randomized, crossover, head-tohead comparison of EPA and DHA supplementation to reduce inflammation markers in men and women: The Comparing EPA to DHA Study

Introduction

Chronic inflammation has been identified[1] as a potential link between obesity and cardiovascular diseases. In people who have obesity, fat cells release greater amounts of inflammatory and signaling molecules (adipokines) that induce insulin resistance, blood vessel dysfunction, and systemic inflammation, all of which increase the likelihood that an artery may become damaged. Once damaged, the artery will express proteins that attract white blood (immune) cells to the location to help with repair and recovery. These immune cells also begin secreting chemicals (cytokines) that signal more immune cells to come to their location.

At this point, the damage should resolve and everything would be fantastic, if that actually happened. However, the chronic inflammation and dyslipidemia associated with obesity continually damages the arteries, never allowing them to fully repair. Accordingly, immune cells (macrophages, especially) continue to accumulate. While all this is going on, LDL particles float through the blood trying to do their job. If a lot of LDL particles are present, then there is an increased chance that some of them become trapped in the damaged artery and become oxidized. If that happens, the macrophages will eat them, thinking they’re doing the body a favor. This engulfment occurs over and over again until the macrophage is filled with lipids and becomes a “foam” cell. Foam cells cannot function properly and ultimately accumulate to form part of the plaque seen in atherosclerosis.

There is a growing body of literature suggesting that the omega-3 fatty acids EPA and DHA have the potential to reduce the inflammatory state associated with obesity. EPA and DHA serve as the precursor molecules from which anti-inflammatory compounds (resolvins, protectins and maresins) are synthesized. A recent meta-analysis[2] of 68 randomized controlled trials (RCTs) and 4601 individuals showed that EPA and DHA supplementation significantly reduced several inflammatory molecules: tumor necrosis factor alpha (TNFα), C-reactive protein (CRP, described further in Figure 1), and interleukin-6 (IL-6).

Figure 1: C-Reactive Protein: what is it good for?

Source: Ridker et al. Circulation. 1998 May.

However, this meta-analysis also revealed notable research gaps. For instance, nearly all the included studies used either a combination of EPA and DHA or used only one of the fatty acids in isolation. It therefore remains unknown whether EPA and DHA have similar or different effects on inflammatory markers. The current study was designed specifically to fill this knowledge gap and determine how EPA and DHA compare when it comes to reducing inflammation.
Obesity is associated with chronic inflammation that plays an important role in cardiovascular diseases. Current evidence suggests that EPA and DHA supplementation is an effective option for reducing inflammation, but whether one is more effective than the other remains unknown. The current study was designed to pit EPA against DHA and find out whether one could be considered more anti-inflammatory than the other.

Who and what was studied?

Become a subscriber to the Nutrition Examination Research Digest to read the full article.

Becoming a member will keep you updated on the most important nutrition studies every month, and give you access to our back catalog of over 500 other articles.

NERD also includes access to Examine Personalized, which includes 150+ monthly summaries on the most important recent studies and access to our database of 10,000+ studies across 600+ health topics.

Stop wasting time and energy — we make it easy for you to stay on top of nutrition research

Try free for a week

Already a member? Please login to read this article.

What were the findings?

Subscribe to the Nutrition Examination Research Digest to unlock this article.

Free 7-day trial!

Already a member? Please login to read this article.

What does the study really tell us?

Subscribe to the Nutrition Examination Research Digest to unlock this article.

Already a member? Please login to read this article.

The Big Picture

Subscribe to the Nutrition Examination Research Digest to unlock this article.

Already a member? Please login to read this article.

Frequently Asked Questions

Subscribe to the Nutrition Examination Research Digest to unlock this article.

Already a member? Please login to read this article.

What should I know?

Subscribe to the Nutrition Examination Research Digest to unlock this article.

Already a member? Please login to read this article.

A Cyber Monday Sale for Science Lovers!

Looking to improve your health using the latest evidence? Examine.com offers a membership and guides based on personalized, comprehensive research analysis.


Click here to save 30% »

Other Articles in Issue #21 (July 2016)

  • Interview: Norm Robillard, PhD
    Gut health is extremely variable and complex, so learning from experts is important. Norm is a microbiologist whose expertise lies in the effect of diet on gut conditions.
  • Let the sun shine in! (to your retinal ganglion cells)
    We've covered the detriments of night-time blue light before, but how important is getting blue light during the work day? This controlled trial looked at its effect on working memory.
  • Heritable bacteria
    How can researchers figure out the role of your genetics in determining the kinds of bacteria you have in your gut? Get over a thousand sets of twins and do some fancy testing. We describe the results here.
  • Dampening exam anxiety with probiotics
    When you're stressed out for an exam, you probably don't instinctively reach for probiotics. Your microbiome may impact anxiety though, and this trial tested a probiotic for anxiety-lessening around exam time.
  • Probiotics and prebiotics for atopic dermatitis
    This meta-analysis looked at all the existing trials on the common type of eczema called "atopic dermatitis", to see if combining pro- and prebiotics helps reduce symptoms.
  • Potential relief for IBS through vitamin D
    Vitamin D isn’t just for bone health. Its role in dampening inflammation and regulating immune responses suggest that it may help in treating IBS, which is directly tested in this randomized trial.
  • Interview: Elle Penner, MPH, RD
    Elle is the senior dietitian at the nutrition and fitness tracking juggernaut MyFitnessPal. We discuss some tips for new moms thinking about diet considerations.
  • Heavy menstrual bleeding in athletes
    An increasing proportion of athletes are female, yet the persistent issue of menstruation is rarely researched in the context of athletics. This study gets the ball rolling.
  • Could fasting help treat MS symptoms?
    Multiple sclerosis involves immune attacks on the nervous system. Current treatments address symptoms, but may have substantial side effects. Fasting diets may both help symptoms and regeneration of existing damage.