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5 Foods That Can Make Autism Worse

October 28, 2021

by Alyson ShafferM.Ed. BCBA Owner

Autism, or autism spectrum disorder (ASD), is diagnosed in 1 in 54 children, according to the CDC. The condition is associated with an array of challenges, including abnormal social skills, developmental delays, communication problems, and behavioral issues.

According to research, over 70% of children with autism have at least one co-existing physical or mental health condition, and 40% have two or more of them. Among children with autism:

  • 30-61% have ADHD
  • 11-40% have anxiety disorders
  • 7% have depression
  • Over 50% have chronic sleep problems
  • 32% are overweight (2-5-year-olds)
  • 16% are obese (2-5-year-olds)

In addition, kids with autism are 8 times more likely to have gastrointestinal issues compared to those who don’t have the condition. And among adults with ASD, 26% have depression and 4-35% have schizophrenia (compared to 1.1% of the general population).

All of these challenges and symptoms can range from mild to severe. And food can have an impact on severity.



Autism is not caused by one specific thing in the brain; there are actually 8-10 different factors that influence abnormal brain function.

ASD brains viewed through SPECT imaging that are wildly overactive – often due to an inflammatory process. For others, we see brains with dramatic under-activity, which may be due to a toxin or some type of insult or injury to the brain.

This is one of the reasons why it is so important to look at brain function when coming up with a treatment plan for ASD. Throwing medication-tipped darts in the dark can hurt people. But there is one thing that ALL people with ASD should do regardless of whether their brains are overactive or under-active…eliminate anything that can hurt their brain.



It is important to realize that the food you eat is either medicine or it is poison. It is either helping your brain, body, and mind or hurting them. Here are the top 5 foods to avoid as they can make ASD and co-occurring condition symptoms worse.


When casein (one of the proteins in dairy) mixes with stomach acid, it produces something called an exorphin. Exorphins bind to the opioid receptor sites and can result in a myriad of troubles – brain fog, spaciness, inability to concentrate, and a numbness to pain, just to name a few.

Dairy is also problematic because it is considered one of the most pro-inflammatory foods in the Standard American Diet. According to a growing body of evidence, including a 2018 study in Pharmaceuticals, inflammation is strongly associated with autism and is also commonly linked to immune system dysfunction. This study shows that neuro-inflammation and neuro-immune abnormalities are key factors in the development and maintenance of ASD.

Avoiding anything that promotes inflammation is critical for anyone with autism. In our experience, when people with ASD removed dairy from their diet, they began talking more, their hyperactivity was reduced, and bowel problems were resolved.


Research shows that gluten—a mixture of proteins found in grains such as wheat, barley, and rye—can increase systemic inflammation when ingested. In fact, your body can create antibodies to gluten which can fire up, or inflame, your brain. Gluten also decreases good bacteria in the gastrointestinal system, which is associated with an increased likelihood of feeling anxious, stressed, or depressed. The gut-brain connection in autism is real, according to findings in a 2019 study.

Gluten seems to particularly negatively affect the functioning of the cerebellum. Located at the back bottom of the brain, the cerebellum is involved with motor and thought coordination and is essential for processing complex information. Through the brain imaging work at Amen Clinics, we have discovered that those with ASD already often have decreased functioning of their cerebellum—consuming gluten can just make it much worse.

Although the research on gluten-free diets is mixed, many parents of children with autism report seeing improvements in symptoms when they eliminate gluten from their child’s meals.


In the U.S., per capita consumption of corn products has risen from 28.4 pounds per year in 2000 to a whopping 35.2 pounds per year in 2019, according to Statista. Since 1972, corn has been the top pesticide-using crop in the nation, based on findings from the USDA. A growing body of research, including a 2013 study in the journal Entropy, suggests a potential link between exposure to the herbicide glyphosate and the risk of autism.

Additionally, corn has the unhealthiest fatty-acid profile (high in omega-6 fatty acids that promote inflammation, compared to omega-3 fatty acids that are anti-inflammatory) of any grain. Yes, you read that right, GRAIN. Corn is NOT a vegetable. Corn has been found to be a breeding ground for fungi, with a 2015 study identifying 46 fungal isolates derived from maize grains. There is simply nothing truly beneficial and many potentially harmful things that can come from eating corn.


Not only is sugar pro-inflammatory, but it also increases erratic brain cell firing and it is very addictive. In addition, research appearing in Frontiers in Endocrinology found that people with ASD, like those with type 2 diabetes, have impaired glucose tolerance and excessive levels of insulin (a condition known as hyperinsulinemia). Because of this, consuming sugar may magnify improper insulin signaling.

Research in Plos One also shows that children with autism who also suffer from gastrointestinal distress have poor metabolism of sugars. In these children, scientists found deficiencies in the levels of enzymes and transporters involved in the digestion of sugars.

Avoiding sugar and refined carbohydrates and increasing lean protein consumption can dramatically improve concentration and judgment, and decrease impulsiveness.


2019 study suggests that the spike in autism may be connected to the preservatives found in processed foods. Other research points to a possible link between autism symptoms and artificial ingredients in our food supply. Avoid all additives, preservatives, dyes and artificial colors, artificial flavorings, and artificial sweeteners. Although these things are not really “foods”, they are unfortunately in so many food products that we wanted to list them here.

If you or a loved one has ASD, paying close attention to the foods being consumed is particularly important. For our patients with autism, it is often recommend to try the elimination diet—eliminating gluten, dairy, sugar, corn, soy, and other categories of potentially allergenic foods for one month. Then add these back one at a time and be alert for reactions to them, which would indicate that your child should permanently avoid that food.


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