Schoolchildren could be given regular daily doses of fish oil supplements in an attempt to improve their behaviour and concentration in the classroom. Ministers are awaiting the results of a Food Standards Agency review into the effects of Omega 3, it was revealed yesterday. If, as some scientists believe, Omega 3 is shown to have a beneficial impact, ministers are prepared to consider giving children daily doses in liquid or capsule form.

It is not clear whether the supplements would be compulsory, and whether schools would be responsible for administering them. Teachers' leaders yesterday warned that they would not want school staff being given responsibility for a health-related issue that should involve parents.

The Department for Education and Skills yesterday stressed that next steps depended on the outcome of the review and further research. The education secretary, Alan Johnson, said: "The government is committed to ensuring that children are provided with healthy food and nutrients during the school day, not just to aid their physical health but to ensure they study hard and behave well.

"The Food Standards Agency is conducting a systematic review of research looking at the effect of nutrition and diet on performance and behaviour of children in schools. This includes investigating studies that have used Omega 3 and 6 supplements in schools. While this work is not yet concluded, we will examine its results with interest.

Scientists are divided on the merits of Omega 3. While there have been studies suggesting that it can lead to improved results in the classroom, some experts have questioned its medical benefits.

Steve Sinnott, general secretary of the National Union of Teachers, said yesterday that while teachers welcomed children eating healthier food which would improve their concentration and behaviour, he would not want teachers being given the responsibility for administering fish oil supplements. "Teachers have welcomed government guidelines on healthier school meals and the ban on vending machines selling fizzy drinks and crisps," he said. "But we would be concerned - if fish supplements were to be introduced as a matter of routine - about teachers being given responsibility for this. It should be a matter of parental choice too."

Sarah Teather, the Liberal Democrat education spokeswoman, added: "It is important to provide parents with the information they need, but that is a far cry from compulsory mass medication. There is a danger the government is trying to use such studies to divert attention from their failure to provide a good education for all our children."