Following on from my last post dispelling the link between sugar and hyperactivity, today I’ll look at the evidence for diet in controlling attention deficit hyperactivity disorder (ADHD) courtesy of a recently published review paper on this area in the journal Pediatrics.
ADHD is a condition characterised by excessively inattentive, hyperactive (unusually active or over-active) and impulsive behaviour in children – to a degree that is inappropriate for their age and development.
ADHD responds well to stimulant drug treatment, but concerns about side effects and consequences of long-term medication use leaves many parents seeking alternative and complementary treatments, with dietary changes being top of the list.
Researchers from the Children’s Memorial Hospital in Chicago critically reviewed published studies looking at the effect of different diets and supplements on children with ADHD. Common dietary changes included restricting sugar, avoiding food additives and preservatives (known as the Feingold Diet), an elimination diet of known allergy foods, and supplementation with omega-3 fish oil capsules.
Supporting the conclusion of my last blog post on sugar and hyperactivity, there was little evidence to support a link between sugar or artificial sweeteners affecting ADHD symptoms. The popular food additive elimination Feingold diet also came out poorly with little evidence to support its benefit.
There was evidence that a small group of children may react adversely to dyes and preservatives in foods and could benefit from elimination diets. Due to the complicated nature and often impractical application of such diets though, this dietary approach is not an endorsement that they should be followed by all children with ADHD.
There was some positive news mixed in within results. Some success was seen for use of a hypoallergenic diet where foods such as cow’s milk, eggs, nuts and cereal foods are excluded. The downside is the dietary changes required to follow such a diet can be very difficult and disruptive for children and families.
Iron and zinc supplementation in children who are deficient appears to offer a small benefit, but the key phrase here is ‘who are deficient’ – taking lots of these minerals in already well-nourished children offers little benefit with potential for harm if taken at high enough dosages.
Clinical trials with omega-3 fish oil supplements showed a modest benefit in treating ADHD, but are well below the benefit achieved with current drug treatments. Because of the ease of supplementation and low risk of adverse health problems, such an approach appears to offer far greater value than restrictive, burdensome elimination diets that have poor evidence for a benefit.
A ‘Western style diet’ high in fat, refined sugars and processed foods was associated with ADHD while a more ‘healthy’ diet pattern high in vegetables, fruit, wholegrains, folate, and fish was linked to a lower risk of ADHD.
What it all means
Parents considering trialling popular alternative dietary treatments to manage ADHD in their children should be aware of the limited evidence to support a benefit for most treatments – especially ones that have a very restrictive approach to dietary choices.