Studies investigation the potential of omega-3 supplements to improve cognition and behavior in children have yielded inconsistent results, which prompted the authors of the new review to ask if this could be due to the Omega-3 Index (O3I) or the omega-3 dose used in the studies.
The new review, published in Nutrients, indicated that an O3I of 6% is needed to see the cognitive benefits of omega-3 supplementation in children.
“There seems to be some evidence that significant cognitive effects of n-3 LCPUFA supplementation can only be shown when the post-intervention O3I is increased and reaches at least 6%,” wrote scientists from the Open University of the Netherlands, University of Wollongong, and Maastricht University.
“However, due to the limited number of studies for which recalculation of the O3I equivalence was possible, this result should be considered with caution.
“Additionally, there seems to be some evidence that a dosage ≥450 mg DHA + EPA per day does lead to improved cognition in typically developing children and adolescents.”
A monumental task
Commenting independently on the study’s findings, Harry Rice, PhD, VP of regulatory & scientific affairs for the Global Organization for EPA and DHA Omega-3s (GOED), told us: “By taking on the monumental task of this review, the authors have addressed an important knowledge gap regarding the cognitive benefits of omega-3 supplementation in a very important demographic.
“While it's clear that more research is necessary, we now have further evidence that not only is there a cognitive benefit of omega-3 supplementation in children, but the benefit is dependent upon a threshold omega-3 index and a minimum EPA/DHA intake.
“One thing the authors mentioned that I want to reiterate is that large interindividual differences can exist in response to omega-3 supplementation. For this reason, omega-3 blood levels need to be measured, minimally at baseline and at the end of the study. Without these measurements, it's difficult to analyze the data and draw reasonable conclusions.”
The researchers identified 33 studies for inclusion in their review, all of which were placebo-controlled randomized controlled cognition trials with participants aged between 4 and 25 receiving EPA and/or DHA omega-3 supplements. Of these, 21 studies followed typically developing participants, while the other 12 followed participants with a disorder, such as attention deficit hyperactivity disorder (ADHD).
A positive effect on cognitive measures was found when studies reported that the O3I increased to at least 6%.
The Omega-3 Index measures the level of long-chain omega-3 fatty acids, EPA+DHA, in red blood cell membranes expressed as a percent of total fatty acids.
An Omega-3 Index (O3I) greater than 8% is is related to the highest protection in terms of cardiovascular health.
“It seems likely that to show positive effects of n-3 LCPUFA supplementation, a sufficient n-3 LCPUFA level in the body should be achieved, which appears to be an O3I of more than 6% for cognition,” wrote the researchers. “It is important to note that many of the studies investigating the effect of n-3 LCPUFA supplementation on cognition included in this review did not include measurements of n-3 LCPUFA levels in the body.
“If future n-3 LCPUFA supplementation studies include blood levels, as suggested by the International Society for the Study of Fatty Acids, possibly a more precise target range for cognitive functioning can be determined, similar to the one available for cardiovascular health.
“Additionally, considering the large interpersonal difference in response to LCPUFA supplementation, it seems prudent that future studies utilize a personalized LCPUFA supplementation dose approach.”
The researchers also noted that half of the studies with typically developing children found that a daily dose of at least 450 mg DHA + EPA showed cognitive improvements.
No effects were seen in children with disorders, they added.
2020, 12(10), 3115; doi: 10.3390/nu12103115
“Effect of Omega-3 Long Chain Polyunsaturated Fatty Acids (n-3 LCPUFA) Supplementation on Cognition in Children and Adolescents: A Systematic Literature Review with a Focus on n-3 LCPUFA Blood Values and Dose of DHA and EPA”
Authors: I.S.M. van der Wurff et al.