Dietary supplements are products intended to improve or enhance the diet.
Dietary supplements include vitamins, minerals, herbals and botanicals, and many other products. They come in a variety of forms including tablets, capsules and powders, as well as drinks and energy bars.
Some people think that some individuals on the autism spectrum have a range of nutritional and metabolic problems. These include low levels of nutrients, high levels of oxidative stress (a chemical state within cells that can increase cellular damage) and difficulties with metabolic processes (such as digestion).
Some people think that these nutritional and metabolic differences may be the cause of some of the core features of autism (such as impaired communication and social difficulties) and related issues (such as challenging behaviours).
They also think that some of these problems can be overcome by taking one or more dietary supplements, sometimes in combination with other therapies such as special diets.
The National Institute for Health and Care Excellence (NICE) reported that some dietary supplements may have some limited benefits for some children and young people on the autism spectrum beyond the benefits provided to other people. However it also reported that:
"... the evidence was very limited and further randomised placebo-controlled studies are required to corroborate the existing evidence for ... dietary supplements in children and young people with autism".
NICE made the following observations on the use of dietary supplements for adults on the autism spectrum:
"... there is very little evidence regarding safety and efficacy for... vitamins, minerals or supplements for the treatment of autism. Moreover, it is important to bear in mind that ... some dietary supplements can be associated with adverse side effects and/or interact and perhaps interfere with the action of other supplements or prescribed drugs".
Eating a healthy and varied diet is important for good health. Food and drinks provide a range of nutrients and all vitamins and essential minerals are just that – essential for good health. If too little of any of these nutrients is consumed nutrient deficiencies can occur, which cause ill health.
Consuming too much of any of these nutrients can also cause poor health. It is unusual to consume too much via foods, however taking dietary supplements with high levels of nutrients does carry a risk of nutrient overload. Some diseases (such as cystic fibrosis), some conditions (such as cerebral palsy) and other factors (such as breast-feeding) increase an individual’s needs for some nutrients.
There is evidence that some individuals on the autism spectrum may have nutritional and metabolic problems. For example, some autistic people eat restricted diets which are nutritionally imbalanced and can lead to severe nutrition deficiencies. Symptoms of severe deficiencies include skin rashes, mouth sores, limps, unexplained irritability, eyesight changes and severe ill health. The effects of these can be life threatening and life changing. There is also evidence that some individuals on the autism spectrum may have other nutritional and metabolic problems that have less severe, but behaviourally or medically significant effects.
However, the number of individuals on the autism spectrum who have these problems is not clear. It is also not clear whether these problems or differences are any more common in individuals on the autism spectrum than in other individuals. Possibly, these problems cause or worsen symptoms (of autism or related issues). Or maybe they arise because of autism, or they could be completely unrelated to autism. Nobody knows.
Most dietary supplements provide the same benefits for people on the autism spectrum as they do to people who are not on the autism spectrum. They do not appear to provide any additional benefits to people on the autism spectrum, according to a limited amount of research evidence of sufficiently high quality. Some dietary supplements may make some problems worse for some children and young people on the autism spectrum according to a limited amount of research evidence of sufficiently high quality. There is no high quality research to suggest that any dietary supplements provide any benefits to adults on the autism spectrum.
Further research is required to replicate and extend research into those dietary supplements which appear to be effective. Any such research should involve people on the autism spectrum to review the efficacy and ethical basis of the intervention.
Please read our Disclaimer on Autism Interventions