The Dietary Science Foundation
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When children with ADHD were given the same diet as highly allergic children, the majority of them saw a significant improvement in their symptoms. The researchers behind the study think there is a form of ADHD that can be induced by food. Other research also suggests that ADHD is linked to allergic diseases. These connections need to be examined using sound scientific methods.
In 2011, Dutch researchers published a scientific study in the medical journal The Lancet. Children between four and eight years old with ADHD tried an elimination diet for five weeks. The diet is extremely strict and consists of only a few foods including rice, turkey, lamb, lettuce, carrots, cabbage, pears and water. The idea was to exclude everything the children could possibly be hypersensitive to for a few weeks: milk, cereals, eggs, fish, coloring agents and other additives found in many of today’s foods.
Using this diet, 60 percent of the children more than halved their ADHD symptoms. In the control group, who were given standard advice about a healthy diet, there was no change. The researchers behind the study think this shows that there is a food-induced ADHD. Read the study here: Effects of a restricted elimination diet on the behaviour of children with attention-deficit hyperactivity disorder (INCA study): a randomised controlled trial.
The idea that ADHD could be due to food hypersensitivity is not new. In various studies scientists have excluded certain food items (such as wheat or artificial colors) from the diet of children with ADHD, but with no clear effect. The theory behind the elimination diet is that individuals may be sensitive to completely different things. After a few weeks on the strict regime, different food items are added to the diet, one by one, in order to find out what individual children react to.
In large epidemiological studies researchers have found correlations between ADHD and allergies, which could support the theory that ADHD may in some cases be affected by a hypersensitivity to food. ADHD is associated with an approximately 40-60 percent higher risk for allergic rhinitis and a 30 percent higher risk of atopic eczema. The increased risk for asthma is around 30 percent.
In reverse studies, researchers looked at people with atopic eczema and found an increased risk for both ADHD and autism. Children who have had atopic eczema early in life also appear to have a higher risk of developing ADHD early.
When the Dutch study was published it was written about in the Swedish newspaper Svenska Dagbladet: Kostbyte kan lindra adhd. The study has been criticized because it was not blinded. The parents of the participating children were well aware of the change in their children’s diet, which may have influenced the results through what is known as the placebo effect. But the strong links that exist between hypersensitivity and ADHD suggest that it needs further investigation. It’s important that children with ADHD get the best possible treatment.