Although this wasn’t the outcome the Australian research team were expecting, Harry Rice, vice president of regulatory and scientific affairs for the GOED (Global Organization for EPA and DHA Omega-3s), told Nutraingredients it was a well-designed study with some important findings.
“For example, the investigators found a significant relationship between baseline omega-3 levels and measures of self-regulation, executive function and ADHD symptoms,” he said.
Rice surmised that had the trial employed more subjects who were performing at a lower level at baseline, the treatment effects would have been positive.
“This is where recognising study limitations, as the current investigators have done, can lead to the stronger design of subsequent research. Having followed the work of some of these investigators, I have no doubt that subsequent studies will address these issues,” he added.
The researchers cited two main factors that may have contributed to the absence of treatment effects. Firstly, due to the pilot nature of the study, the sample size was small (78 children in total), which may have meant that the study was too ‘underpowered’ to show an effect. Secondly, the children in the cohort were performing higher then normal at baseline, which potentially led to a ‘ceiling effect’ that limited the scope for improvement during the trial.
They said that a larger, adequately powered clinical trial is warranted and that this should target children who may have suboptimal self-regulation or executive function.
Self-regulation is defined by Murray et al as “the act of managing cognition and emotion to enable goal-directed actions such as organizing behaviour, controlling impulses and solving problems constructively”. It is made up of three domains: cognitive, behavioural and emotional self-regulation.
Previous intervention trials involving primary school aged children with ADHD (a condition associated with deficits in self-regulation and executive functions) have shown benefits for working memory, cognition, inattention, hyperactivity and behaviour. Less evidence exists for preschool aged children. Therefore, the aim of the Omega Kid Study was to investigate the effect of omega-3 on self-regulation and executive functioning in this younger age group in a 12-week, randomised, double-blind, placebo-controlled pilot trial.
The researchers hypothesised that omega-3 supplementation would result in improved self-regulation and enhanced executive functioning.
Children were given either a placebo or a 1.6g dose of omega-3 (combined EPA and DHA) daily during the intervention. The study involved two clinic visits - at baseline and at 12 weeks post-intervention - during which the children completed practical assessments and their carers/parents completed behavioural questionnaires. They also provided fingerprick blood samples to assess the HS-Omega-3 Index (the amount of EPA plus DHA in the red blood cells).
Post-intervention, although there were no improvements in executive functioning or self-regulation there was a significant three-fold increase in the HS-Omega-3 Index in the treatment group.
In addition, at baseline, correlations were found between the HS-Omega-3 index and measures of self-regulation, executive function and ADHD symptoms. The researchers said this supported the notion that children with lower levels of omega-3 in their red blood cells have poorer self-regulation and executive function.
They cited a meta-analysis that suggested children and adults who have lower levels of omega-3 may benefit most from supplementation, and said this was supported by their findings at baseline.
The researchers therefore concluded that although no treatment effects were found in typically developing children, further research is required to target children with sub-optimal self-regulation who may benefit most from omega-3 supplementation.
Roach,L.A.; Byrne,M.K.; Howard, S.J.; Johnstone, S.J.; Batterham, M.; Wright, I.M.R.; Okely, A.D.; de Groot, R.H.M.; van der Wurff, I.S.M.; Jones, A.L.; et al.
“Effect of omega-3 supplementation on self-regulation in typically developing preschool-aged children: results of the Omega Kid pilot study - a randomised, double-blind, placebo-controlled trial”