Autism and Nutrition

child sitting on the ground with toys

Autism or “Autism Spectrum Disorder” is a term used to describe a group of disorders that affect the brain. You might have heard that there are different diets and supplements that may help with the symptoms of autism. Read on to learn about the current research that is being done.

What is autism?

Autism is a disorder that affects the way a person’s brain works. It is the most common mental disorder affecting children. About 1 in 160 children worldwide has autism.

What are the symptoms of autism?

Common symptoms of autism may include:

  • Trouble communicating and interacting with people
  • Behaviour that is different than other people
  • Less interest in food or uncommon food preferences
  • Less interest in activities with others
  • Trouble with motor skills including picking up small objects, catching a ball and riding a bike

Autism affects each person differently and can range from mild to severe.

When is autism usually diagnosed?

Autism is usually diagnosed in early childhood when signs first start.

What is the treatment for autism?

There is no known cure for autism. Treatment is based on the individual. It may include helping individuals cope with their symptoms through education and skill development, self-help, socialization and play. 

What diets or nutrients are linked to helping the symptoms of autism? Do they work?

Children with autism may limit their food intake or have food preferences. Many children with autism also have gastrointestinal symptoms like constipation, diarrhea or abdominal pain. As a result, children with autism are sometimes low in certain nutrients. Some of these nutrients have been studied to see if giving children supplements of these nutrients may help with autism symptoms. However, more research is needed. Before giving your child any of the following supplements, speak with your child’s dietitian or health care provider first.

Vitamins and Minerals

Multivitamin and mineral supplements: Some results have shown a multivitamin and mineral supplement may help improve sleep and digestive problems in children with autism..  Multivitamin and mineral supplements may also help your child get extra nutrients that might be low or missing from their diet. Speak to your doctor or dietitian before starting any supplement to make sure it is safe.

Vitamin B6 , magnesium and iron: The research on these vitamins and minerals has shown that they are not likely to help reduce symptoms of autism. If you are concerned that your child might not be getting enough vitamins and minerals, speak to your doctor or dietitian. A dietitian can assess the quality of your child’s diet and give advice on how to boost certain nutrients.

Omega-3 Fats

Some research has shown that many children with autism have low levels of omega-3 fats. Omega-3 fats like DHA are important for healthy growth and development. Research studies have found that supplementing with omega-3 fats may help reduce anxiety in children and teens with autism, however it did not help reduce other symptoms of autism like communication and irritability. More research is needed. If you would like to learn how to increase omega-3 in your child’s diet, connect with a dietitian


The research on probiotics and autism has shown mixed results. More research is needed before recommendations can be made. If you have questions about probiotics, speak with your dietitian.

The Gluten-Free, Casein-Free Diet

The Gluten-Free, Casein-Free Diet is a diet free of gluten and casein. Gluten is the main protein in wheat and other grains such as rye and barley.. Casein is the main protein in dairy products such as cow’s milk, cheese, yogurt and ice cream. Some research has shown that this diet may improve some symptoms of autism like hyperactivity and communication, but it has not shown to improve digestive symptoms. More research is needed before this diet can be recommended for children with autism. If you would like to try this diet, make sure to seek the guidance of a dietitian for support and monitoring. This diet can be restrictive and low in certain nutrients like calcium and vitamin D which are important for growth and development. 

I want to try a special diet for my child who has autism. What else should I know? 

Before putting your child on a special diet speak to a dietitian.

A dietitian can do a full nutrition assessment on your child and discuss the pros and cons of the diet. Ongoing work with a dietitian is recommended to help lower the risk of nutrient deficiencies. 

How can a dietitian help?

A dietitian can:

  • Make sure your child is getting all the nutrients they need to grow and be healthy
  • Give you helpful and practical strategies to overcome eating challenges
  • Give suggestions to help with any digestive issues your child may have
  • Give advice about special diets and nutritional supplements

 Many dietitian services are covered by provincial or employee health benefit plans. Use our Find a Dietitian tool to connect with a dietitian today.

Bottom line

More research is needed to support a link between autism symptoms and nutrition. If you are considering a supplement or a special diet, speak with your child’s doctor or a dietitian first. They can help you make the right choice and lower the risk of possible side effects or nutrient deficiencies.

You may also be interested in:

Constipation in Children
Picky Eaters: Commonly Asked Questions
Family-Friendly One-Week Sample Menu Plan
Kid Friendly Award Winning Recipes
This article was written and reviewed by dietitians from Dietitians of Canada.

Last Update – November 18, 2021

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