The Importance of Diet for Those with Autism


For years, Brittyn Howard watched as her brother struggled with food options, inspiring her to become a dietician. Here's why diet is crucial for those with autism.
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Growing up with a brother on the autism spectrum wasn’t easy. I remember our “bonding activity” was participating in his ABA therapy when I was six years old, trying to help teach him the meaning of simple words such as “on, over and under,” colors and numbers. I watched him finally gain verbal skills at four, and other “developmentally appropriate skills” well past their years. It wasn’t until my mother began to explore diet and nutritional supplements that I started seeing a dramatic change in him. We found out he had a myriad of food intolerances when he was a toddler which ended up affecting me as well. This led me down the path to later become a registered dietitian specializing in children with autism spectrum disorder (ASD) and teach others what I had spent my whole life learning.

ASD is defined as “a range of conditions characterized by challenges with social skills, repetitive behaviors, speech and nonverbal communication, as well as by unique strengths and differences” by Autism Speaks. Autism is viewed as a puzzle—their official symbol is even a puzzle piece. There are many pieces that play into this puzzle, such as the behaviors outlined above and common therapies in ASD such as speech pathology, occupational therapy and behavioral therapy, which also play into these puzzle pieces. There is no known cure for ASD, which makes it quite puzzling in and of itself. However, nutrition is often a piece of the puzzle that gets left out.

Children with ASD typically have heightened sensory sensitivity, involving hearing, sight, touch, taste and smell. Eating is a function that typically involves all of these senses, which can be overwhelming for a child with ASD. Many children will develop food selectivity which, in some cases, can become very severe—even limiting themselves to less than five unique foods. Our bodies were not made to survive on such little range of nutrition, which can cause children with such limitations to have nutrient deficiencies and other health problems caused by lack of sufficient nutrition. This can cause the brain to not work at its best capacity, possibly even increasing autistic symptoms.

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Another area to take note of is the intestinal microbiome. This refers to the collection of bacteria or microorganisms that inhabit our gastrointestinal system. We can have anywhere from 300-1000 different species of bacteria in our gut, which make up around 100 trillion cells. Gut bacteria can be both “good” and “bad.” The makeup of your gut biome is heavily impacted by your diet, with plant-based, high-fiber foods contributing more to the “good” bacteria, and meats, dairy, sugar or other processed foods contributing to the “bad” bacteria. Bad bacteria can cause chronic constipation, diarrhea, excess intestinal gas, chronic bad breath, food intolerances and allergies, vitamin deficiencies, yeast overgrowth and even neurological problems, among other symptoms.

Nutrition is the very basis of life and is what sustains our bodies, organs and brain. Good nutrition increases the ability and efficacy of our body functions, while poor nutrition depletes it.

Children with autism commonly have intestinal dysbiosis, which means that they have an irregular amount (and often an overgrowth) of bad bacteria in their GI tract. This could be caused by an extremely limited and fiber-poor diet, but can also be a manifestation of autism itself. For this reason, it is important to stress high-fiber foods along with a quality probiotic in order to keep the gut biome healthy and functional.

Nutrition is the very basis of life and is what sustains our bodies, organs and brain. Good nutrition increases the ability and efficacy of our body functions, while poor nutrition depletes it. Poor nutrition can also cause systemic inflammation in the body (which is also seen in ASD, along with inflammation in the brain). By maintaining a diet rich in whole, plant-based foods, we are able to give the body the vitamins, fiber and nutrients that it is craving. Many children with ASD are prone to food intolerances, which can also alter their body’s inflammation. Food intolerance testing can be very helpful in these cases to get to the root cause of GI problems or other behavioral problems.

So, I know you’re thinking that getting a child with ASD and severe food selectivity to eat a whole food, plant-based diet is easier said than done, and you’re right. For a child that does have food selectivity, getting them into the appropriate services to help expand their diet repertoire is key.

Start by identifying a feeding team comprised of an occupational therapist (certified in feeding therapy), speech-language pathologist and registered dietitian (check out Autism Dietitian) at the very minimum. Other great members of a feeding team would include a behavioral therapist and pediatrician. As a dietitian specializing in children on the autism spectrum, I favor the SOS Method to Feeding by Dr. Kay Toomey. You can learn more here to find a provider in your area. Another great organization that helps with feeding problems in children is Feeding Matters.

It is called the autism spectrum for a reason.

Each child is different in their own unique way. Because of this, it’s important to evaluate each child on an individual basis. What works for one child might not be the best approach for another. If you are a parent struggling with a child with ASD that has food selectivity, you are not alone. Get connected with providers who specialize in feeding in your area and begin to build a feeding team for your child. I also urge you to not try any drastic diet or nutritional supplement without the guidance of a registered dietitian or physician.

Like I said before, there is no known cure for ASD. Nutrition cannot completely heal your child from autism, but it can help with the underlying root cause of many symptoms. Autism is truly a puzzle, and nutrition is just one of the pieces.