On a diet of junk food, our children are frenzied, over-fed and under-nourished. Joanna Blythman relishes a practical guide that aims to stop the poison

Has there been an explosion in the numbers of children with behavioural difficulties? If you read tabloid press reports of “feral” children supposedly terrorising their neighbourhoods, mindless teenage vandalism and binge drinking-fuelled adolescent violence, you could be forgiven for getting the impression that the nation’s youth has never behaved so badly.

Teachers, doctors and parents are, for the most part, more circumspect in their assessment of the youth of today, preferring to adopt a new lexicon of off-the-peg labels for children who are hard to handle, along with those who appear to have learning difficulties. Conduct disorder, oppositional defiant disorder, speech and language disorder, attention-deficit hyperactivity disorder (ADHD), dyslexia, specific reading difficulties, dyspraxia, developmental co-ordination disorder, autistic spectrum disorders... take your pick.

We do indeed seem to have some sort of crisis on our hands. The statistics are scary. In Britain, 20 to 25 per cent of children now meet the criteria for one or more of the conditions listed above. Indeed, the crisis has become so marked that the Government has recently felt the need to spend an additional Pounds 342 million on school behaviour-improvement programmes.

Globally, meanwhile, the World Health Organisation predicts a 50 per cent rise in child mental disorders by 2020.

What on earth is going on here? Why are so many children revealing these problems? And what do we do about them? Drug them when they are young because we are told that there is nothing else that can be done, then lock them up when they are older and throw away the key? Or should we be taking a different tack?

Dr Alex Richardson, a former teacher and now the UK’s leading authority on how nutrition affects behaviour and learning, certainly believes we should.

She argues that too many children are struggling with behaviour, mood and learning problems because they are nutritionally-challenged. Although British children never seem to stop snacking and grow fatter by the day - by 2020, at least one fifth of British boys and one third of British girls will be not just overweight, but obese - too many of them suffer from a modern form of malnutrition. In a nutshell, they are simultaneously over-fed and undernourished. Their diet has changed radically and drastically over the past few decades. British children now consume, for example, 25 times more confectionery and 30 times more soft drinks than they did in 1950.

In her book, Dr Richardson points out that labels such as ADHD or dyspraxia are descriptions, not explanations, and she will rattle the cage of many professionals whom she accuses of denying the role that nutrition plays in such conditions, almost to the point of professional negligence. “Advice about food and diet currently feature absolutely nowhere in standard practice for either assessing or treating children’s behavioural and learning difficulties,” she writes. And yet, as she points out, food and diet affect us all at the most fundamental level, because without the right nutrients, it is simply not possible for our brains and bodies to develop and function properly.

They Are What You Feed Them is a practical, systematic list of suggestions for dietary and lifestyle changes that can be made quite easily and which might help alleviate problems. As a senior research fellow at Oxford University, Dr Richardson has spearheaded numerous groundbreaking studies into the role of nutrition on the brain. And her book offers welcome hope to parents who may be at their wits’ end. Many of her observations will resonate with teachers who see children with apparently intractable behaviour problems on a daily basis.

The book is an illuminating discussion of the vital role key nutrients play in behaviour and performance which goes way beyond the standard medical texts, with their emphasis on the most severe dietary disorders. In extreme cases, lack of vitamin B3, we learn, can cause Pellagra, which manifests itself in dermatitis, diarrhoea and dementia. But reading this book, you may wonder just how many children there are who, as a result of their inadequate, junk-loaded diet, are impaired by mild, sub-clinical Pellagra, which manifests itself in hyperactivity, inappropriate social behaviour, moodiness and problems with perception. And how many more children are there like the 12-year-old boy -described in the book - whose mother has worked out that his dyspraxia symptoms are worse when he eats a high-carbohydrate diet with little protein or essential fatty acids ?

One of the great strengths of Dr Richardson’s book is that it contains enough medical and scientific detail to substantially enhance the reader’s understanding of how nutrition affects behaviour and performance. Most parents and teachers know, for instance, that sugary drinks are not beneficial for children, even if they are not sure exactly why. But she fleshes out this limited knowledge by explaining that a tired, irritable grumpy child with rapid mood swings may simply be showing sugar sensitivity and explains how blood sugar “rushes”, of the kind supplied by a typical fizzy drink, can eventually deplete the adrenal glands, so producing even more alarming peaks and troughs in mood, energy levels and behaviour. And parents struggling with difficult children will doubtless find discussions, such as the substitution of omega-3 fatty acid supplements for the overused drug, Ritalin, most compelling.

At times, They Are What You Feed Them seems irritatingly repetitive and rather patronising in tone. Its derivative, Gillian McKeith-esque title does it no favours. It comes close to being a sprawling textbook on nutrition, because it covers an astonishing amount of ground, everything from “good” versus “bad” fats, through allergies and anti-nutrients (pesticides and heavy metals), to lists of pernicious food additives. It is saved, however, by lucid internal organisation and frequent summaries which help the reader cut to the chase.

Joanna Blythman is the author of Bad Food Britain (4th Estate pound;7.99)