If an apple a day can keep the GP at bay, so too a bowl of cereal in the morning can perhaps keep the children alert through the day.
Cereal at breakfast cuts the inevitable decline in performance throughout a day by more than half, dieticians at the King's College of London say. They have reviewed several earlier studies on the issue.
Their conclusion is that a low glycaemic index (GI) wholegrain breakfast, such as porridge, muesli or bran enriched cereal can remarkably improve the concentration of the child. A high GI breakfast, such as white toast, in contrast, fails the test.
The researchers pinpointed a study of schoolchildren who were given a cereal breakfast and were compared over four days with those who had a glucose drink or no breakfast at all.
Dr Katrina Campbell, one of the reviewers, said: "Consuming breakfast cereal reduced the deficit to attention and for some aspects of memory prevents the deficit altogether."
Skipping breakfast altogether was found to reduce the ability to recall a word list and a story read aloud.
It also cut performance on visual perception and spatial memory, verbal fluency and academic performance.
Studies which looked at students who took part in school breakfast programmes achieved a significant increase in maths grades and much less days off or late attendances.
The review showed a general agreement in the literature that breakfast can have a positive effect on 'brain performance' when compared to not having breakfast.
Dr Campbell said: "Breakfast cereal consumption has a potentially significant role in improving morning cognitive performance."
A study of 1,300 schoolchildren carried out for the Home-Grown Cereals Authority a few years ago also had showed that those who ate breakfast were more accurate, faster and over 10 per cent better at memory tests.
And a report by the Soil Association and Business in the Community, based on interviews with local authority education chiefs, revealed that pupils who ate school meals made with fresh, unprocessed ingredients and who had access to drinking water showed improved concentration and longer attention spans, and were calmer and more alert in class.
"Foods high in sugar and refined carbohydrates cause the body to react quickly to bring the sugar level down, so you end up with low sugar levels, which induce fatigue and lack of concentration," said Deborah Colson, a nutritional therapist at the Brain Bio Centre, which takes a nutritional approach to mental health and behavioural problems.
"That is why having a sugar bun for breakfast is almost as bad as having no breakfast at all. Much better to have a bowl of porridge or an egg on wholegrain toast, which releases sugar slowly into the bloodstream. Blood glucose is the main supply of energy to the brain and you need a steady trickle, not a sudden hit," Colson said.
Cut down on fizzy caffeinated drinks and food additives, which can affect sleep and concentration in children. Go for fresh fruit and vegetables, wholegrains, seeds, nuts and two portions of oily fish a week. "A quarter of the dinner plate should contain protein, a quarter starch and a half vegetables," advises Colson. Dehydration adversely affects mental performance, so make sure children drink plenty.