Laura Stevens and her team carefully evaluated all the research on diet and ADHD until 2011. They provide clinical suggestions recommending that doctors can let families know that some children may react adversely to artificial food colours [AFCs], flavours and whole foods, but that diet is not the main cause of ADHD. They report that the evidence from the scientific literature is that those more likely to respond to diet are younger children, those with allergies, and those who also have irritability and sleep problems. They are supportive of parents who wish to try diet, those whose children have not responded to usual medicines, and even those who are also using medicines. They suggest the support of a dietitian to help with choice of alternative foods, and to ensure the diet meets the child’s nutritional requirements. They suggest that parents use a before and after diet trial assessment questionnaire, and/or tests of handwriting, reading aloud and maths, to assess changes when challenge foods are given. Finally they suggest that parents should starting adding whole foods back to test for sensitivity, once the diet is established.
See Stevens LJ, Kucze T, Burgess JR, Hurt E, Arnold LE. Dietary Sensitivities and ADHD Symptoms: Thirty-five years of Research. 2011clinical Paediatrics 50(4) 279-293
They described the various work wisely considering 3 different types of diet.
The first was the early work researching the Feingold K-P Diet which excluded artificial food colours [AFCs], flavours and salicylates. Careful studies showed that some children did react but not nearly as many as Feingold had predicted. So it was proved that AFC, flavours and salicylates did not cause hyperactivity. Unfortunately where yellow dye was used as the test dye it was put in chocolate biscuits, later known to cause reactions in some.
The second type of diet studies investigating just AFCs were considered separately. These studies are important as it is much easier to study AFC using a double-blind-placebo-controlled methodology preferred for effectiveness of new medicines. AFCs can be hidden in fruit juice so families do not know when the children are getting the AFCs or just fruit juice. Again this group of studies showed that some ADHD children reacted with results reaching statistical significance. They even showed that some non-ADHD children reacted. They note that it was not clarified whether diet responders were more likely to be atopic or not, and that the pharmacological aspect was important.
The third group of researchers were those who investigated exclusion of whole foods, such as dairy, wheat, eggs, legumes, corn, soy, and chocolate. They also excluded AFCs, flavours and preservatives. AFC and preservatives were the most common culprits but no child reacted only to them! These studies also showed that mood changes, especially irritability, and sleep problems should also be assessed at the same time as ADHD features.
The reviewers of all the studies wisely point out that just removing AFCs may not be a complete treatment for some diet responders, and that the diets that also exclude many whole foods may be difficult to stick to for more than a few months. They also point out that no researchers have studied the effects of artificial flavours or natural salicylates alone. And they note that using challenge biscuits containing chocolate and wheat would mask a diet effect in those who were also sensitive to these foods.
A Joan Breakey comment on this review.
This is an important article which provides an important overview of diet and ADHD. The reviewers have shown that diet can be said to have a role in some children with ADHD, even by critics who insist on double-blind-placebo-controlled trials. It is worth remembering that the initial question was whether diet caused ADHD, and when that was disproved many thought that the research proved that diet had no role at all. I support their appreciation that the research on AFCs has not included the need to attend closely to the dose of dyes, and I emphasize that does not include a role for artificial flavours, which I found were used in 10 times the dose of colours, so probably contribute to reported reactions to high additive foods.
Much work done in Australia has added to what has been discussed here. The RPAH team have shown a role for salicylates, the inclusion of allergy, and a role for dairy and wheat where gut symptoms occur. Flavours have been emphasised in my clinical studies, which also reported reactions to whole foods as well as AFCs and flavours, and natural chemicals. In my study group chocolate was shown to cause reactions in 80% of those who reacted to dyes, and soy sauce in around 50%. As well early research unfortunately did not take into account the week of withdrawal symptoms that most children over five years of age have when first excluding suspect foods. A greater effect for diet in younger children can be explained by their likelihood of “clearing” metabolic breakdown compounds of excluded foods and additives in only one or two days, unlike school-age children who often take one to 4 weeks, and the likelihood of young children’s reactions happening sooner and clearer, whereas older children may take up to 5 days to react.
It is interesting that in the review the role of the dietitian is limited to just replacing foods and maintaining nutrition but I have been able to do much more than that because of my unique opportunity to do research in a different way. I investigated the diet itself not by investigating the effect of one diet but by beginning with the Feingold diet in 1977 and allowing families to report what their child did and did not tolerate. These were open trials but each family reported what their own child tolerated or not. I kept adjusting the beginning diet according to what caused reactions in most families. By allowing families to test what they could tolerate once they responded to the initial diet I found that each diet responding child or adult progressed to their own individual diet. I followed up over 2000 families over 30 years so am confident that these findings have real-world power. See Are You Food Sensitive? for all the detail.
We can now say that the best diet to begin with in 2013 is one minimising additive colour, flavour, most preservatives, foods high in flavour including natural salicylates, amines and monosodium glutamate, and whole foods suspect in the family: decided after taking a Family Sensitivity History. This forms the Family Elimination Diet.
I have been able to work closely with parents on many diet and effect issues such as withdrawal, effects of age on reactivity, interaction with allergy foods, and other whole foods which do not show as positive on allergy tests, environmental factors, the diet difficulty, nutrition, just what is causing reactions, how to test foods in such a way that maximum tolerance is managed.