These are the findings of a Kings College, London (KCL) study, which think the supplements rival that of pharmacological treatments for the condition and serve as a basis for ‘personalised treatment’ to those affected.
“The omega-3 supplements only worked in children that had lower levels of EPA in their blood, as if the intervention was replenishing a lack of this important nutrient,” says professor Carmine Pariante, senior researcher from the Institute of Psychiatry, Psychology & Neuroscience at KCL.
“For those children with omega-3 deficiency, fish oil supplements could be a preferable option to standard stimulant treatments.
“Our study sets an important precedent for other nutritional interventions, and we can start bringing the benefits of ‘personalised psychiatry’ to children with ADHD.”
The study, carried out in collaboration with China Medical University in Taichung, Taiwan, was met with a considered reaction from experts, who centred on the small sample size and varied results.
“This is a small study with mixed findings and the omega-3 fatty acid eicosapentaenoic acid (EPA) may not be helpful for impulsivity, which can be very debilitating for people with ADHD,” says Dr Bernadka Dubicka, chair of the Royal College of Psychiatrists’ child and adolescent faculty.
“More research is needed before fish oil supplements can be recommended as a treatment for ADHD.”
No inflammation marker impact
John Stein, emeritus professor of physiology at University of Oxford, adds that the study had “many caveats,” in particular the small sample size and why the statistics failed to show any effects on markers of inflammation.
“But the study begins to answer why omega 3 studies in this area are so contradictory,” he remarks.
Writing in Translational Psychiatry, the team began a randomised controlled trial, in which 92 children with ADHD aged 6-18 were given high doses (1.2 grams (g)) of the omega-3 fatty acid EPA or a placebo for 12 weeks.
Levels of polyunsaturated fatty acids (PUFAs) in the blood were measured before and after treatment, to examine the effects of baseline endogenous EPA levels on treatment response and the effects of EPA treatment on PUFAs levels.
The team found that children with the lowest blood levels of EPA showed improvements in focused attention and vigilance after taking the omega-3 supplements,
However, these improvements weren’t seen in children with normal or high blood-levels of EPA. In addition, for those children with high pre-existing blood-levels of EPA, omega-3 supplements had negative effects on impulsivity symptoms.
“Our results suggest that fish oil supplements are at least as effective for attention as conventional pharmacological treatments among those children with ADHD who have omega-3 deficiency,” says Dr Jane Chang, co-lead researcher from the Institute of Psychiatry, Psychology & Neuroscience at KCL.
“On the other hand, it is possible to have too much of a good thing, and parents should always consult with their children's psychiatrists since our study suggests there could be negative effects for some children.”
A step too far?
The study points to previous studies that have found inconsistent findings of omega-3 supplementation on ADHD symptoms, with overall effect sizes being relatively small.
Standard treatments offered to parents whose children have ADHD include stimulants such as methylphenidate. The effect size of improvement in attention and vigilance from methylphenidate is 0.22-0.42.
In comparison, the effect sizes in the trial of omega-3 supplementation for those children with low blood-levels of EPA were larger, at 0.89 for focused attention and 0.83 for vigilance.
“The paper presents the data in a considered manner, but the press release broadens the implications further,” says Dr Kate Langley, senior lecturer, school of psychology at Cardiff University.
“It suggests that, in those with low baseline levels, treatment by omega-3 supplementation may be as effective as conventional pharmacological treatments.”
Dr Langley thinks this takes the findings of the study too far as the exploratory findings are from a small sample and relate to cognitive improvements rather than the core ADHD symptoms which are the main focus of most treatments for ADHD.
“The suggestions that the effect size improvements here are bigger than those in other treatments should also be treated with caution because they are on a small sample with large margins for error.”
The European Food Safety Authority (EFSA) currently recommends an average EPA + Docosahexaenoic acid (DHA) intake of 250 milligrams per day (mg/day) in the paediatric population.
On the basis of a systematic review of available randomised controlled trials, the UK’s National Institute of Health and Clinical Excellence, a public body of the Government’s Department of Health, stated in 2018 that “dietary fatty acid supplementation is not recommended for the treatment of ADHD in children and young people.”
Source: Translational Psychiatry
Published online: DOI: 10.1038/s41398-019-0633-0
“‘High-dose eicosapentaenoic acid (EPA) improves attention and vigilance in children and adolescents with attention deficit hyperactivity disorder (ADHD) and low endogenous EPA levels.”
Authors: Jane Pei-Chen Chang et al