Omega-3 supplements for five years did not affect the rate of cognitive decline in the elderly study participants, compared to supplements of lutein and zeaxanthin or placebo, according to findings published in JAMA.
“We’ve seen data that eating foods with omega-3 may have a benefit for eye, brain, and heart health,” said Emily Chew, MD, deputy director of the Division of Epidemiology and Clinical Applications and deputy clinical director at the National Eye Institute (NEI), and leader of the Age-Related Eye Disease Study (AREDS). However, data from the AREDS 2 did not find any benefit under the conditions of this particular study.
“Contrary to popular belief, we didn’t see any benefit of omega-3 supplements for stopping cognitive decline,” said Dr Chew.
Omega-3s and brain health: Filling the knowledge gaps
There is good and fairly consistent data from epidemiological studies of a positive relationship between fish intake/ plasma DHA levels and cognition. Intervention trials, however, have yielded conflicting data.
A 2013 review (Advances in Nutrition, Vol. 4, pp. 672-676) by Tommy Cederholm (Uppsala University, Sweden), Norman Salem Jr (DSM Nutritional Products), and Jan Palmblad (Karolinska Institutet, Sweden) concluded that, “Recent advances bring us closer to providing the general public with new evidence-based recommendations on fish and fish oil intake to facilitate memory function during aging.
“We may conclude that longitudinal observation studies on fish intake and DHA plasma concentrations in older healthy adults are mainly positive when it comes to cognitive health,” they wrote. “Intervention studies on EPA and DHA supplementation in healthy older individuals are so far null.
“When EPA and DHA is given to individuals with [mild cognitive impairment] or age-related cognitive impairment the data now appear to be positive. However, when patients with established Alzheimer’s disease are supplemented with EPA and DHA it appears that no clear benefit is achieved. A major concern is that the studies in general have been too short. There might also be subgroup effects because of the carriage of [APO E4] alleles or risk factor burden in general not yet clearly identified.”
There are numerous gaps in our understanding of how long term omega-3 intakes may influence cognitive function, and these will be discussed during the NutraIngredients-USA Cognitive Health Online Summit on September 2.
Dr Richard Bazinet from the University of Toronto, Dr Scott Minton from Nordic Naturals and Harry Rice, PhD, VP of regulatory & scientific affairs for the Global Organization for EPA and DHA Omega-3s (GOED) will join me, Stephen Daniells, for an extensive discussion on the current understanding of omega-3s for brain health.
For more information and to register, please click HERE.
“Omega-3s, from fish or supplements, should be consumed throughout life”
Coming on the JAMA paper, Dr Rice told us: “Given the number of clinical trial failures involving a wide range of pharmaceutical substances for cognitive decline, it's not clear to me why the expectation is that omega-3s will halt cognitive decline.
“Omega-3s, from fish or supplements, should be consumed throughout life. GOED recommends omega-3s for maintenance of optimal health, including supporting cognitive function.”
Study details
AREDS 2 participants were randomly assigned to one of four groups: Placebo; omega-3 only; lutein + zeaxanthin; or omega-3 plus lutein/zeaxanthin. A total of 3,501 people underwent the cognitive function testing.
Results collected over five years indicated that there were no statistically significant differences in change of scores for participants randomized to receive supplements vs those who were not.
“The AREDS2 data add to our efforts to understand the relationship between dietary components and Alzheimer’s disease and cognitive decline,” said Lenore Launer, PhD senior investigator in the Laboratory of Epidemiology and Population Science at the National Institute on Aging.
“It may be, for example, that the timing of nutrients, or consuming them in a certain dietary pattern, has an impact. 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.”
Big limitations
Writing in the TalkingNutrition blog, Dr Eric Ciappio, a scientific leader at DSM Nutritional Products, noted that there was no true placebo group in the study, and that the AREDS2 cohort was not the right one to use for a study of omega-3s and cognitive health (for example, about 45% of the participants used statins, which have been reported to decrease DHA concentrations, and no measure of APOE4 status was made of the participants, to name but two reasons). Ciappio also questioned the dosage used, noting that the DHA component of the supplement was only 350 mg, while a recent meta-analysis found that daily DHA doses of over 580 mg were needed to observed cognitive function benefits.
To read the full blog entry, please click HERE.
Source: JAMA
2015, Volume 314, Number 8, Pages 791-801, doi:10.1001/jama.2015.9677
“Effect of Omega-3 Fatty Acids, Lutein/Zeaxanthin, or Other Nutrient Supplementation on Cognitive Function - The AREDS2 Randomized Clinical Trial”
Authors. E.Y. Chew, T.E. Clemons, E. Agron, L.J. Launer, F. Grodstein, P.S. Bernstein, for the Age-Related Eye Disease Study 2 (AREDS2) Research Group