While recent research indicated that omega-3 supplementation may help prevent at-risk patients from developing psychotic disorders such as schizophrenia, a new study from the NIH indicates that nutrient supplements of omega-3 fatty acids and lutein/zeaxanthin have no significant effect on cognitive function.
The results go against previous research and long-standing assumptions that suggest omega-3s protect brain health.
“Contrary to popular belief, we didn’t see any benefit of omega-3 supplements for stopping cognitive decline,” said Emily Chew, MD, researcher and deputy clinical director at the National Eye Institute (NEI), part of NIH.
The study, one of the largest and longest of its kind, included about 4,000 participants from the Age-Related Eye Disease Study 2 (AREDS2) study who underwent cognitive function testing, including evaluations of immediate and delayed recall, attention and memory, and processing speed. All of the participants (mean age 72.7 years, 57.5% women) had early or intermediate age-related macular degeneration (AMD) and were assigned to one of four supplement groups: placebo; omega-3 [docosahexaenoic acid (DHA, 350 mg) and eicosapentaenoic acid (650 mg)]; lutein and zeaxanthin; and omega-3 and lutein/zeaxanthin.
Researchers found that there was no statistically significant difference in change of scores between participants randomized to receive supplements vs. those who were not. Those taking omega-3s had a composite cognitive function score of −0.19 (99% CI, −0.25 to −0.13) compared to −0.18 (99% CI, −0.24 to −0.12) for those not taking omega-3s (difference in yearly change, −0.03 [99% CI, −0.20 to 0.13]; P = .63). Participants randomized to receive lutein/zeaxanthin had a composite cognitive function score of −0.18 (99% CI, −0.24 to −0.11) compared to −0.19 (99% CI, −0.25 to −0.13) for those who did not take lutein/zeaxanthin (difference in yearly change, 0.03 [99% CI, −0.14 to 0.19]; P = .66). No significant interactions between omega-3s and lutein/zeaxanthin were found either.
Overall, participants across the various supplement groups continued to decline at a similar rate, showing no significant benefit of omega-3 or lutein/zeaxanthin supplementation. More research will need to be conducted to confirm these findings.
“It may be, for example, that the timing of nutrients, or consuming them in a certain dietary pattern, has an impact,” said researcher Lenore Launer, PhD, of the National Institute on Aging. “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.”