More threads by David Baxter PhD

David Baxter PhD

Late Founder
The devil in their diet
16 August 2004
Geoff Watts

Parents have long believed that artificial food colourings could cause hyperactive behaviour in children. Now, at last, scientists seem to have proved it.

Twelve months ago, at school and in his Glasgow home, seven-year-old Ryan Gallacher was all but uncontrollable. Then, in August last year, his father Alex changed Ryan's diet. Off the menu went anything with artificial food additives. Ryan's behaviour improved - dramatically.

Around 20,000 children have been diagnosed as having what is variously known as "hyperkinetic disorder" or "attention deficit and hyperactivity disorder" (ADHD). But some commentators believe that the true number could be 10 times that. To Alex Gallacher, a down-to-earth Glaswegian who would normally have little time for "alternative" theories, the part that additives had played in causing Ryan's problem was blindingly obvious. But many clinicians and scientists who work on additives remain cautious if not downright dismissive about the alleged link.

The woeful gap between parental conviction and scientific rigour makes a difficult problem even harder. It needs to be bridged - and the best hope of doing so lies in research at the University of Southampton. Its preliminary findings suggest that, to some degree at least, parents may have been right all along.

Ryan's problems began when he was just 18 months old. "He was excluded from his nursery for inappropriate behaviour," Alex recalls. "He was very excitable, very jumpy. Not just raucous, it was completely beyond that."

Nothing had improved by the time Ryan began school. Alex would be summoned by teachers as often as two or three times a week. "I'd get a call saying, 'Your son is running through the corridors screaming'. Or they'd say, 'You've got to come, he's hiding under a desk holding his head in his hands'."

Educational and family psychologists considered various explanations, from parental disharmony to sibling rivalry. But nothing added up. Ryan's older brother was fine. "I could let him play with the kids in the street," says Alex. "But not Ryan. I had to make excuses to him why he couldn't go out, because we knew that as soon as he did, there was going to be trouble."

Alex became increasingly frustrated and angry. He and his wife Phoebe almost split up. "There was a point at which I couldn't work properly because my mind was constantly on what was happening to Ryan. The strain was destroying us."

Salvation came from a Sunday- newspaper article on diet and behaviour. Out went all foods containing additives - and Ryan's six-year nightmare drew rapidly to a close.

The best-known treatment for ADHD is a drug called Ritalin, which first gained notoriety in the States. The number of prescriptions being issued in Britain - up from 90,000 in 1997 to well over 200,000 in 2002 - reveals its rising popularity here.

A hint of psychiatry's caution in linking the disorder to diet can be gleaned from the brevity of the relevant section in a Royal College of Psychiatrists fact sheet. "There is a small body of evidence about the effect of diet on some children," says the leaflet. "A few may be sensitive to certain foods. If parents notice that specific foods worsen hyperactivity, these may be avoided. It is best to discuss this with the specialist."

That's it. So, who is right: the doctors or the parents? Enter Professor John Warner of Southampton General Hospital, a physician with a long-established interest in additives. His team's study of their effects, published recently in the authoritative journal entitled Archives of Disease in Childhood, used methods of a kind that are standard in all careful medical research.

Among the 400 children who took part were some who showed signs of hyperactivity and some who didn't. Their parents were asked to keep them on a diet free of all additives and artificial preservatives for one month. In the second and fourth weeks, each child had to drink a daily bottle of fruit juice. During one week it was pure; during the other it was laced with a cocktail of additives. The drinks themselves were indistinguishable in taste and colour, and parents weren't told which was which.

The test drink contained four widely used food colourings: sunset yellow, tartrazine, carmoisine and ponceau 4R, and also the preservative sodium benzoate. The researchers conducting the study assessed each child at weekly intervals using tests that are routine in behaviour-disorder clinics.

Most importantly, parents, too, rated the everyday behaviour of their children. They looked for signs such as switching from one activity to another, talking or interrupting a lot, fiddling with objects, and general restlessness.

The results showed a clear distinction between the parents' assessments and those of the psychologists. The latter found no significant difference between the effect of the two drinks; the parents did.

So, what to make of the apparent contradiction? One of Warner's colleagues, the psychologist Professor James Stevenson, thinks that he can explain it. "Children were coming along to a clinic, meeting a bright young tester who was interested in them, and they were on their best behaviour. It wasn't a context that would elicit inattention, distractability and the rest. But parents see kids when they're tired, they see them in the evening, on the bus, in the supermarket queue."

In short, in real life. This wouldn't be the first time that measurements made within the clinic have failed to detect what is more apparent outside it.

The Southampton team's conclusions are unequivocal: "The observed effect of food additives and colourings in this community sample is substantial." For Stevenson in particular, the findings prompted a change of heart. "I'd worked in hyperactivity for a number of years, and originally thought that diet was probably important only in an exceptional, odd group of children. Having done this work, I've changed my mind."

His guess is that within the general population there's a range of behaviour that is affected by nurture as well as nature. "Additives seem to be shifting that distribution of behaviour towards the more hyperactive end."

Neither Stevenson nor Warner suggests that additives are the only factor; but their effects are large enough to take seriously. Not least, adds Stevenson, because most of them are there only for marketing purposes.

Heartened by these findings, Warner is planning a further study. This, like its predecessor, will be partly financed by the Food Standards Agency, a body that takes the issue seriously.

Among parents eager to take part in the new study is Vickie Gilfillan, a single mother whose son Jacques, aged six, showed the first signs of hyperactivity when he was just eight months old. "He wouldn't sleep, he screamed all the time, he would throw things, and his temper tantrums were horrendous. As he got older, it got worse and worse."

She is enthusiastic about the new study. "I heard of the last one from a report on the TV. I e-mailed them to tell them about Jacques. I was quite lucky because my mother went through the same problem with my brother, so we managed to spot it early on. Jacques now has a largely additive-free diet.

"If Jacques goes to a birthday party, it's a nightmare. You can't stop children going to parties, but I don't know what he's eating. And you can't tell other parents what to give the children."

As for young Ryan up in Glasgow, he, too, rebelled at first over the loss of sweets. But his parents' will prevailed, and the change in his behaviour has now persisted for a year. "Far from me being called up to the school," says his father, "he has even won a 'pupil of the week' award. That in itself is just mind-blowing. When people see Ryan now, they ask if it's the same boy."

Small wonder that Alex Gallacher talks about the effects of additives with a crusading zeal.

At the beginning of July, the food giant Birds Eye announced its intention to remove all additives from its products. An opportunistic gimmick? Or a sign that the food industry is finally getting the message.

  • Sunset yellow (E110) is a dye used in, among other foods, orange jellies and squashes, apricot jam and packet soups. It's also in Smarties, and at least one variety of Lucozade.
  • Tartrazine (E102), one of the more controversial colouring additives, is another yellow dye used in fizzy drinks, ice cream, sweets and jams. Also used in Sainsbury's processed peas and Batchelors mushy peas.
  • Carmoisine (E122), a red dye, is used in jellies, sweets, blancmanges, marzipan and cheesecake mixes. You'll also find it in novelty cakes, such as the Harry Potter ones, but not, as of next month, Burtons Jammie Dodgers - it's being replaced with a natural dye.
  • Ponceau 4R (E124), also red, is used in tinned fruit, jellies and salamis. Smarties and Simpsons cakes also contain it.[/list:u]
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