The agency commissioned researchers at the University of Teeside to identify and evaluate studies on the effects of certain nutrients on children aged between four and 18 years.
However the researchers found that only 29 of 69 studies identified by keyword mapping were randomised and case controlled, and could therefore be included in the review. In many cases even these studies were said to lack quality in research methodology and reporting, and failed to account for confounders.
The results may be disappointing for the supplements industry, but given the current state of affairs there is a feeling that government rubber-stamping may be premature on the basis of current evidence. The report is not an outright denial of supplements' potential benefit, but rather an indictment of the quality of research to date.
Five of the studies looked at fish oil supplementation for children with symptoms of learning and behavioural disorders, two looked at vitamin and mineral supplementation, six looked at short term sugar intake in ADHD children, and 15 looked at the importance of breakfast. One study simply looked a 'good diet' in the first year of school.
The researchers said the studies reporting mixed results from which firm conclusions could not be drawn, and only six of the 29 studies originated from the UK - an important point since other factors such as habitual dietary intake, locality and family context could skew the results. Moreover, over half of the studies were less than one month in duration.
In the case of omega-3, the studies to date have concentrated on children with behavioural problems rather than mainstream children, making it difficult to extrapolate results for the general population.
Thus, the agency said "there is insufficient quality evidence to reach firm conclusions on the effect of nutrition and dietary changes on learning, education or performance for all schoolchildren".
Its dietary advice for this group therefore remains unchanged: Maintain "a diet lower in fat, salt and sugar but high in fruits, vegetables and complex carbohydrates, in addition to being physically active".
The FSA called for more research, but said that future studies should be large enough to provide meaningful and reliable results" and should take into account other factors affecting children's development and performance.
Indeed, some of the first publicity about the FSA review came through national newspapers, which postulated that omega-3 supplementation for children could become common-place in UK schools as a result of the review.
There has been considerable interest recently in the potential for omega-3 to help improve behaviour and learning capacity, particularly in children with behavioural problems such as ADHD.
So much so, in fact, that Dairy Crest was recently emboldened to claim that its St Ivel Advance milk with omega-3 could improve some children's ability to learn - a claim that brought the might of the Advertising Standards Agency down upon it since it was said to misuse the findings of the Oxford-Durham study on omega-3 supplementation with a very different dosage.
Adam Kelliher, managing director of Equazen, whose supplements were used in the Oxford-Durham study, told NutraIngredients.com: "In the main, the FSA's conclusions are correct in that the published research to date is quite thin."
But he said that upcoming evidence, such as the independent, randomised, placebo-controlled Middlesborough trial involving 250 mainstream school children and supported by the local education authority, is likely to provide support for omega-3 supplementation.
Kelliher said it is regrettable that the Middlesborough trial, which will be published by the end of this year, could not be included within the review.
"We hope that the FSA remains open to the volume of upcoming trials which we think should persuade them of the proof of mechanism."
As to recommending omega-3 supplementation for all children, he said it would be a "big and controversial challenge", because of concerns about the UK becoming a 'nanny state'.
But it is certainly good that the government is looking into the matter, and it may at some point see fit to endorse omega-3 supplements through information provision.