FAB RESEARCH COMMENT:
These researchers are to be commended for using a randomised, double-blind, crossover design for this study. It is also commendable that they studied only children previously reported by their parents to show adverse reactions to artificial food colourings (AFC) - as a failure to do this would not provide an adequate test of the hypothesis that some
children react badly to such additives.
Despite this, the results of this trial provided no evidence of adverse effects of AFC on these children's behaviour.
Obviously the study numbers here were very small, making it extremely difficult for any differences between the intervention and placebo conditions to reach conventional levels of 'statistical significance' unless these really were huge.
However, given the lack of any observable effects - according to either parent and teacher ratings or psychological assessments - it seems safe to conclude that the improvements in their children's behaviour previously reported by these parents following adoption of the 'Feingold diet' are unlikely to have resulted from the exclusion of AFCs themselves.
As the Feingold diet involves major changes to many other
aspects of the diet, however, it is quite possible that any of these might have an influence on children's behaviour.
Food intolerances may be an issue for some children, as many parents of children with ADHD or related behaviour problems report apparent adverse food reactions to many common, if not staple foods (including milk and dairy products, gluten grains, eggs, corn, or soy, as well as some fruits, vegetables and other foods high in salicylates).
Nutrient deficiencies or imbalances are another diet-related factor, as preliminary evidence suggests that some symptoms and features of ADHD may reflect relative deficiencies of 'essential fatty acids'
(long-chain omega-3 and/or omega-6 polyunsaturates), and/or other nutrients involved in normal fatty acid metabolism, such as zinc, and some B vitamins.
Equally, however, numerous other non-dietary factors - including parental expectations, and/or children's responses to the attention being paid to their diet and/or behaviour - could help to explain any genuine behavioural changes previously observed by these parents.
Further studies would be needed to distinguish between these possibilities.
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