The researchers gave 196 ‘typically developing’ 13 to 16 year olds one tablet containing multivitamins and minerals and a daily omega-3 dose of EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid) of 165 mg and 116 mg, respectively or a placebo over 12 weeks.
They saw a deterioration of behaviour for children with low baseline rates of 'disciplinary infringements', but an improvement for children who had high baseline rates.
However, the researchers warned that the general level of disciplinary infringements was low in the school, which made it difficult to judge improvements and the conclusions should therefore be treated with caution.
Large-scale research with stratified offending rates was called for, they said.
“The relationship between diet and behaviour is complex and poorly understood. Childhood malnutrition has been associated with behavioural problems such as in attention, aggression and impaired socialisation.
“Individuals with micronutrient and n-3 PUFA deficiencies may be particularly prone to such anti-social behaviour and aggression,” they wrote in the British Journal of Nutrition.
However, this earlier research typically focused on children with neurodevelopmental disorders like attention-deficit hyperactivity disorder (ADHD).
This latest study looked therefore at the impact of supplementation among ‘typically developing’ adolescents.
One of the researchers behind the paper, Dr Jonathan Tammam, said he preferred to advocate an improved diet in certain teenagers, rather than supplementation.
"In my opinion, an improved diet is a useful - yet perhaps ignored - tool which can be used in combination with additional behavioural measures, but not necessarily in isolation. The balance of evidence available from prisons and schools suggests that broad spectrum improvements in nutrition may be an effective tool," he told NutraIngredients.
They tracked changes in blood levels of omega-3 and -6 fatty acids and the vitamins and minerals, which at baseline were low.
After supplementation omega-3 and -6 levels as well as folate, vitamin C and vitamin D levels improved “significantly”. Meanwhile iron and ferritin were unchanged.
They measured behavioural changes using school disciplinary records as well as Conners’ teacher ratings, which are commonly used to measure child behaviour problems.
On the Conners’ disruptive behaviour scale, the group given the active supplements improved, whereas the placebo group worsened.
During the academic term, school disciplinary infringements increased significantly by 25% in both the supplemented and placebo groups.
When the subjects were split into high and low baseline infringements, the low subset increased their offences whereas the high-misbehaviour subset appeared to improve after treatment.
“Thus, when assessed using the validated and standardised Conners teacher tests (but less clearly when using school discipline records in a school where misbehaviour was infrequent), supplementary nutrition might have a protective effect against worsening behaviour,” the researchers from Oxford University’s department of physiology, anatomy and genetics and department of statistics wrote.
Source: British Journal of Nutrition
Published online ahead of print, doi:10.1017/S0007114515004390
“A randomised double-blind placebo-controlled trial investigating the
behavioural effects of vitamin, mineral and n-3 fatty acid supplementation in typically developing adolescent schoolchildren”
Authors: J. D. Tammam, D. Steinsaltz, D. W. Bester, T. Semb-Andenaes and J. F. Stein