Autism and Nutrition

April is Autism Awareness Month and April 2nd was World Autism Awareness Day. As of 2014, one in every 63 children is diagnosed with Autism Spectrum Disorder. More than 2 million people in the US and more than 10 million worldwide are affected by ASD.

ASD describes a grouping of various developmental disabilities. There are three main classifications of ASD – autistic disorder, Asperger’s syndrome, and pervasive developmental disorder, not otherwise specified, or atypical autism. Autistic disorder, the more classic form, includes significant delays in language, social, and communication skills. Autistic disorder patients may also have unusual behaviors or interests, and may have intellectual disabilities. Asperger’s syndrome is typically a milder form of autism that is characterized by delays in social and communication skills and unusual interests or behaviors. Many people with Asperger’s demonstrate a specific interest or hobby that encompasses most of their time. Asperger’s patients do not usually have language or intellectual delays or disabilities. Atypical autism individuals may demonstrate characteristics of classic autism or Asperger’s, but have fewer, milder symptoms or delays.

So you’re probably wondering what nutrition has to do with ASD. As research continues, many links are being found between ASD and nutrition, indicating that symptoms and what are thought to be co-morbidities of ASD may be treated with diet changes and nutrition supplements.

Autism and Digestive Disorders

Autism is identified primarily as a brain/mental disorder, but research suggests that as many as nine out of 10 individuals with ASD also suffer from gastrointestinal problems such as inflammatory bowel disease (IBD) and “leaky gut.” Symptoms of IBD include constipation, diarrhea, bloating, nausea and GERD, problems many people with ASD suffer from. Leaky gut occurs when the intestines become excessively permeable and leak their contents into the bloodstream. Theories suggest that many individuals with ASD may have trouble digesting gluten and dairy leading to undigested peptides gluteomorphin and caseomorphin leaking into the blood stream and crossing the blood-brain barrier. These peptides have an opiate effect on the brain thought to cause delays in social and language skills and withdrawn behaviors.  What this is like hypothetically is a child with ASD drinking a glass of milk which appears to have a calming effect at first, but it followed by a “withdrawal” and the problematic behaviors.

Gluten-Free, Dairy-Free Diet

A gluten-free, dairy-free diet may help to reduce some ASD symptoms. This means eliminating wheat, rye, barley and foods that may contain additives made with these grains, as well as all dairy products (milk, yogurt, cheese, butter, etc). It is important to work with a Registered Dietitian when doing an elimination diet to help guide you through it and prevent further nutrition deficiencies.

Probiotics and Healing the Gut

Before eliminating gluten and dairy, it is recommended to start a probiotic supplement to “clean up the gut”. The National Center for Complementary and Alternative Medicine defines probiotics as live microorganisms—usually bacteria, but they also can include microbes such as yeast—that people can ingest to increase the population of desirable bacteria in the gut.

A number of recent studies have compared the intestinal bacteria of children with ASD to healthy children and found altered levels, specifically a reduction in the bacteria that promote good intestinal health. One hypothesis is that a leaky gut may allow substances to pass into the bloodstream that harm the brain, so focusing on rebuilding the microbial ecosystem in the gut with protect against leakage of substances.

There are many probiotic supplements on the market. The key things to look for in a probiotic supplement is the number of colony forming units, CFU’s, and the number of strains of bacteria. Our gut contains 30-40 different strains of bacteria, so the more variety you can get in a supplement the better. It is recommended to find a probiotic with at least 10-20billion CFU and 7 or more strains of bacteria. It is best to work with an RD or other natural practitioner who can recommend the best option for you.


Many other nutritional supplements can help support individuals with ASD by strengthening the immune system and improving some symptoms. Omega-3’s, especially DHA (docosahexaenoic acid), play a huge role in brain development and neurological functioning. Studies have shown reductions in anxiety, aggression, hyperactivity and impulsivity with omega-3 supplementation in children with ASD. Longer attention spans, improved language development, reading and spelling skills have also been seen with supplementation of omega-3. The recommended daily dosage is 1.5g of total omega-3 (EPA and DHA). See my post here on how to choose a quality omega-3 supplement.

Vitamin D

Another key nutrient is vitamin D. Vitamin D deficiency is very common, and studies suggest there is a direct link between low vitamin D and ASD. Vitamin D is a fat soluble vitamin that regulates the immune system and reduces oxidative stress and inflammation. Some ASD symptoms may be improved with adequate vitamin D levels. Vitamin D levels can be easily tested with routine blood tests. Taking a vitamin D3 supplement with a specific dosage recommended by your doctor or RD can bring levels up within a few months. It is also believed that maternal vitamin D supplementation may reduce the risk of ASD. Research recommends pregnant and breast feeding women supplement 6000IU/day of vitamin D3.

Clearly, there is much research still to be done on the link between nutrition and Autism, but the research is promising.  Although we know that we cannot cure ASD with nutrition, the studies and case studies show that nutrition therapy and supplements have been helping in families and individuals with ASD in reducing symptoms.

Information obtained from:

Today’s Dietitian January 2013 Issue – Autism Spectrum Disorder — Research Suggests Good Nutrition May Manage Symptoms

Contemporary Pediatrics -Managing autism symptoms through nutrition

Scientific American – Gut Bacteria May Play a Role in Autism

Lurie Center for Autism: Omega-3 Fatty Acids

Vitamin D Council