AREDS2 Trial: Omega-3s Don’t Benefit Cognitive Health?

Nutritional OutlookNutritional Outlook Vol. 19 No. 7
Volume 19
Issue 7

Why we should take negative results from the AREDS2 study with a grain of salt for now.

Photo © Wackerhausen

There’s always something interesting to be said about the efficacy and benefits of omega-3 fatty acids. Over the years, research has suggested that omega-3s may benefit numerous aspects of the human condition, including cognitive health.

Before we examine the relationship between omega-3s and brain health, it’s first of all important to clearly establish what cognitive health means. The Centers for Disease Control and Prevention offers this simple yet effective definition: “A healthy brain is one that can perform all the mental processes that are collectively known as cognition, including the ability to learn new things, intuition, judgment, language, and remembering.”1

When discussing the potential effects of omega-3s on the brain, it can be all too easy to lump aspects of mental health-like mood and depression-into the category of cognitive health. For the sake of this discussion, however, the term cognitive health is intended to cover the neural skills related to cognition, such as memory, language, and comprehension.


The AREDS2 Randomized Clinical Trial

One of the most intriguing omega-3–focused trials in the last five years is the AREDS2 randomized clinical trial, “Effect of omega-3 fatty acids, lutein/zeaxanthin, or other nutrient supplementation on cognitive function.”2AREDS2’s primary endpoint focused on eye health in order to evaluate the effects of supplementation with lutein, zeaxanthin, and DHA/EPA omega-3 fatty acids on the progression of age-related macular degeneration.

AREDS2 subjects were administered the original AREDS study supplement-vitamin C (500 mg), vitamin E (400 IU), beta-carotene (15 mg), zinc (80 mg), and copper (2 mg)-with additional subgroups randomized to also receive either 1) lutein (10 mg) + zeaxanthin (2 mg), 2) omega-3 fatty acids DHA (350 mg) + EPA (650 mg), 3) a combination of those four ingredients, or 4) just the control (the original AREDS formula).

One of the longest and most comprehensive studies of its kind, the double-blind and randomized AREDS2 trial was conducted over the course of six years-from October 2006 to December 2012-and involved more than 3,000 adult subjects. Once the trials were completed, researchers omitted data from participants with missing demographic data or incomplete test results, leaving 3,073 unique sets of participant data for analysis.

One of AREDS2’s ancillary studies also looked at how these nutrients influenced the risk of cognitive decline-specifically, Alzheimer’s disease-in the same AMD patients. Of the total AREDS2 patients, 89% agreed to participate in the cognitive arm of the study and undergo cognitive-function testing at baseline, at 2 years, and at 4 years. The tests evaluated immediate and delayed recall, attention and memory, and processing speed.


The Findings

At the end of the six-year trial the researchers analyzed the data, drawing, among others, the following conclusion: “Despite what observational data concerning the nature of the relationship between omega-3s and cognitive health-particularly the risk and onset of Alzheimer’s disease-has suggested, the findings of this study suggest that there is no statistically significant link between the two.”

“Contrary to popular belief, we didn’t see any benefit of omega-3 supplements for stopping cognitive decline,” said Emily Chew, MD, the study’s leader and deputy director of the Division of Epidemiology and Clinical Applications and deputy clinical director at the National Eye Institute (NEI), part of NIH.3

Though the results of the ancillary AREDS2 study may suggest, rather strongly, that the link between omega-3s and cognitive health may be weaker than previously believed, it’s important to remember that the study focused on only one specific form of cognitive decline-Alzheimer’s disease. As is almost always the case, without the support of additional studies, there’s a need to take the findings of this study with a figurative grain of salt. Considering past research done on other parameters of cognitive health, one can easily argue that there is still so much more to the “omega-3s and cognition” story than is being presented here.

In a press release announcing the study results, Lenore Launer, PhD, senior investigator in the Laboratory of Epidemiology and Population Science at the National Institute on Aging, pointed out, for instance, that more research can be done on targeting when supplementation should, if at all, commence. “It may be, for example, that the timing of nutrients, or consuming them in a certain dietary pattern, has an impact,” Launer said. “More research would be needed to see if dietary patterns or taking the supplements earlier in the development of diseases like Alzheimer’s would make a difference.”3

When it comes to the relationship between omega-3s and overall brain health, a large body of existing evidence suggests there may be links between the two. We also should not discount potential links to depression and other components of mental health.4,5 Given the undeniably complex nature of the human brain, it appears that the jury on brain health (including cognitive health) and omega-3s may still be out.


Melissa DellaBartolomea is a content marketing specialist and writer for NutraScience Labs (Farmingdale, NY), a subsidiary of Twinlab Consolidation Corp.


Also read:

2016 Omega-3 Science Update

2016 Omega-3 Market Update: Fish Oil, Krill Oil, Astaxanthin, and More




  2. “Effect of omega-3 fatty acids, lutein/zeaxanthin, or other nutrient supplementation on cognitive function: the AREDS2 randomized clinical trial,” The Journal of the American Medical Association, vol. 314, no. 8 (August 25, 2015): 791-801
  4. Osher Y et al., “Omega-3 fatty acids in depression: a review of three studies,” CNS Neuroscience and Therapeutics, vol. 15, no. 2 (Summer 2009): 128-133
  5. Peet M et al., “Omega-3 fatty acids in the treatment of psychiatric disorders,” Drugs, vol. 65, no. 8 (2005): 1051-1059
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