‘Autism diets’ lack clear evidence of benefit

Parents of children with autism often try diet changes or supplements to help improve the condition. A new review concludes that there is little solid evidence that any work.

In children with autism, a variety of gastrointestinal problems and associated symptoms have been often reported which has led to the popularising of a variety of dietary approaches to treat the condition. Wheat and dairy avoidance feature prominently as too do special elimination diets targeting food dyes and additives, yeast, simple sugars and naturally occurring salicylates in foods.

Concerns have been raised about the lack of solid evidence for any special ‘autism diet’. This is an area where personal anecdotes abound to support many of the popular autism diets rather than good science. Nutritional deficiencies are a risk in some of the stricter elimination diets. This is a concern considering the nutritional needs of the growing child so they should not be endorsed and adopted if they may not be giving a therapeutic benefit to most children.

So what does the scientific evidence say about autism diets when tested in a clinical trial? A new review based on 19 clinical trials looked at the benefits of special diets or supplements on autism symptoms. Gluten-free and casein-free diets, digestive supplements, methyl B12 and omega-3 fish oil supplements were the most common treatments tested.

There was no solid evidence than any of the treatments made a significant difference in children with autism. Where there were some positive effects, there was not enough consistent evidence to make a firm conclusion. And in some of the trials, children given a placebo showed greater improvements than those taking omega-3 supplements. Most trials were small in size and of short duration, further making it difficult to offer a firm conclusion either way about the benefit or not of the treatments.

What it all means

It is plausible that certain dietary interventions for autism could benefit some children, but not others, but there is no way to know who these children are short of parents going on a merry-go-round of trialling a multitude of treatments. Parents deserve to know if a treatment they are being recommended has sufficient evidence for a benefit. Children with autism are already picky eaters, so it is vital to consider the nutritional impact of any change in the child’s diet. If parents do opt for some form of dietary modification for their child, particularly overly restrictive ones, then professional supervision is recommended to prevent nutritional deficiencies.