How to Detect and Address Gastrointestinal Issues in Children

The criteria for autism spectrum disorder has nothing to say about bowel movements, nausea, or stomach pain. But the fact is that children with autism have significantly more gastrointestinal (GI) problems than their typically developing peers. The reasons for this are not entirely understood, but it is clear that behavioral problems in autistic children can often be improved by appropriate changes in diet and/or feeding therapy. That means it's important to investigate stomach and bowel symptoms quickly, as they can be a major hurdle to your child's development.

Kid in pajamas lays in bed feeling sick, stomachs
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The Facts About GI Symptoms in Autistic Children

Autism spectrum disorder is a developmental rather than a medical diagnosis, but studies suggest that children with autism spectrum (as well as their siblings) are at significantly higher risk of GI problems than typically developing children of the same age.

Risk of GI Problems

A question remains about exactly how much higher the risk is; some sources say it is eight times greater than the norm while others suggest it is significantly less. The same is true of prevalence: some studies suggest that as many as 70 percent of children on the spectrum have GI issues while others mention a figure of about 23 percent. These differences may relate to the structure of the study or the cohort of people being studied. For example, a very small study of autistic children in an autism clinic is likely to yield different results than a large study of autistic children in the general community.

Symptoms of GI Problems

While some GI symptoms are obvious, others can be hard to detect in a young child or a child without the ability to describe the sensations s/he is experiencing. Symptoms of GI problems may include:

  • Constipation
  • Diarrhea
  • Gas
  • Abdominal pain
  • Pain while stooling
  • Nausea or vomiting

Why GI Symptoms Are Prevalent in Children with Autism

There are no definitive answers to the question of why GI symptoms are so prevalent in autism, but there are some clues. For example:

  • At least one study has detected differences in the gut bacteria of autistic individuals. Research suggests that there is a strong connection between gut and brain.
  • A study discovered that the neurotypical siblings of autistic children are also more likely than typical peers to have GI problems. This suggests that there may be an inherited aspect of GI symptoms in autism.
  • Autistic children experience more anxiety than their typical peers. In addition, anxiety-related disorders such as obsessive-compulsive disorder are more common in autistic children than in the general population. Anxiety can cause some GI issues.
  • Many autistic children are extremely picky eaters and a fairly large number also have allergies or food sensitivities. All of these can lead to or result from gastrointestinal problems.

How GI Issues Impact Children on the Autism Spectrum

Gastrointestinal symptoms can be painful, frustrating, and distracting. Even typical children coping with stomach pain and constipation (for example) may develop negative behaviors. Children with autism lack the ability to explain their pain or discomfort, and so "acting out" becomes their only option. In fact, according to one study: "Restricting to ASD children, those with frequent abdominal pain, gaseousness, diarrhea, constipation or pain on stooling scored worse on Irritability, Social Withdrawal, Stereotypy, and Hyperactivity compared with children having no frequent GI symptoms."

In other words, autistic children are more likely to have GI symptoms. GI symptoms can lead to negative behaviors, inattention, and other behavioral problems that are often linked to autism. The obvious conclusion—treating GI symptoms may often improve behavior, learning, and social skills in children with autism. As stated in the study, "Understanding the magnitude of GI problems and their effects on behavior can provide new insight for more effective and appropriate treatment of children who suffer from these problems."

Behavioral problems, while significant, may be only the tip of the iceberg. Children with GI issues lose sleep, another contributor to learning and behavioral problems. And children with autism are much more likely than their peers to be hospitalized for problems like severe constipation.

How to Detect Gastrointestinal Symptoms in Your Child

Some GI problems are self-evident, even in a child with no spoken language. For example, it's hard to miss diarrhea or vomiting. Other symptoms, though, may not be obvious. Some of the harder symptoms to see include constipation and gas. These symptoms are especially difficult to spot in a child who has always had behavioral issues. While you should certainly contact a pediatrician if you suspect GI problems, you can also keep an eye open for some of these clues:

  • Is your child pressing on his stomach or abdomen or pressing up against furniture to compress that part of his body? This is one way to relieve gas pain.
  • Does your child's behavior tend to get worse after a meal?
  • Does your child's behavior tend to get worse after eating certain foods?

If your answer to any of these questions is yes, it's a good idea to contact a pediatrician and ask for a referral to a doctor with experience in treating GI symptoms in autistic children. It's important to find a doctor with specific autism experience because general practitioners are less likely to investigate the problem if it isn't severe.

Addressing GI Problems in Autistic Children

Because the reasons behind and the severity of GI problems vary, treatment varies. In some cases, the problem can be resolved with a simple stool softener. In other cases, however, a change of diet or further testing may be necessary.

Addressing Stress

For some children, stress can be the cause of a range of issues that include GI problems. For children with autism, it may be hard to express or discuss stress or identify its cause.

While you investigate physical problems, you can consider reducing stressful elements in your child's life. Some of these problems may not be obvious to you, so be sure to check in with your child and her teachers and therapists. Common stressors include:

  • Negative interactions with classmates such as bullying
  • Difficulty with schoolwork (many children with autism have learning disabilities)
  • Changes in routine (many autistic children find change very challenging)
  • Sensory challenges ranging from loud school buzzers to buzzing lights to strong smells from new carpets
  • Changes such as a new school, new sibling, divorce, or a death in the family

Addressing Picky Eating

There are many reasons why children with autism may be extremely picky eaters, but the most common seems to relate to sensory challenges and a desire for sameness. Whatever the reason, picky eating (especially when the child refuses any type of fruit or vegetable) can lead to GI symptoms such as constipation and gas. There are a number of parent-friendly approaches to addressing picky eating, but the reality is that these rarely work for autistic children. After giving these techniques your best shot, you may need to visit a feeding therapist. As feeding therapy is a form of behavioral therapy it may well be covered by your insurance.

Investigating and Addressing Intolerances and Allergies

Allergies and food intolerances can cause a range of gastrointestinal problems for many people, autistic or not. If your child seems to be exhibiting GI problems that your pediatrician can't alleviate, it's quite possible that your child has a food intolerance that hasn't yet been diagnosed. Your pediatrician may then refer you to an allergist, but while true allergies may be revealed through scratch tests, less severe food intolerances may still remain elusive.

Often, if this is the case, parents turn to do-it-yourself diet manipulation, placing their child on an "autism" diets such as keto or GFCF (gluten-free/casein-free). If your child happens to have an unidentified allergy or intolerance to gluten, dairy, or certain types of starches, there's a potential that this approach could be helpful. If your child doesn't have such allergies or intolerances, though, there's no reason to think their GI problems will be resolved.

Perhaps the best approach is to work directly with a dietitian or feeding specialist who can help you pinpoint some likely culprit foods and support the process of evaluating outcomes from diet change. Working with a specialist has some additional benefits as well, as dieticians and feeding therapists can:

  • Adjust your child's diet without sacrificing nutrition
  • Help your child expand his food choices
  • Help you and your child's teachers and therapists to properly evaluate the outcome of any given diet change
  • Establish long-term changes and help you stick with them

Avoiding the Placebo Effect

Because the symptoms of autism are so amorphous and every child grows and matures over time, it can be extremely difficult to determine whether a small change in diet is really making a positive impact. As a result, many people believe they see positive or negative outcomes that don't really exist based on evidence; this is sometimes called the placebo effect.

To make an accurate assessment of whether a therapy is working, you will need to take a baseline measurement of symptoms and behaviors and then remeasure those symptoms and behaviors after trying each therapy. So, for example, you might measure number, duration, and intensity of temper tantrums per day before and after removing a food from your child's diet. This can be a tricky project, so having a therapist working with you to create the right measurements and assess outcomes can be very helpful.

A Word from Verywell

It's very important to note that, while gastrointestinal symptoms can certainly make autism symptoms worse, eliminating the symptoms will not eliminate the autism itself. Thus:

  • Changing your child's diet will change their behavior only if the diet was a cause of physical discomfort. Changes in diet that are unrelated to gastrointestinal issues are very unlikely to have any positive impact at all or, worse, could lead to improper nutrition.
  • Even if positive behaviors result from changes in diet, your child will still be autistic. They may, however, be less prone to outbursts of anger, more focused, and more willing to say "yes" to social interactions.
  • While it is important to identify and treat GI issues in autistic children, it is just as important to be sure your child has adequate nutrition. This is one very good reason to work with an expert when you make changes to your child's diet.
2 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Son JS, Zheng LJ, Rowehl LM, et al. Comparison of fecal microbiota in children with autism spectrum disorders and neurotypical siblings in the Simons Simplex CollectionPLoS One. 2015;10(10):e0137725. doi:10.1371/journal.pone.0137725

  2. Ferguson BJ, et al. Abstract 126.138 Associations between dietary composition and gastrointestinal symptoms in autism spectrum disorder. Presented at: International Meeting for Autism Research; May 10-13, 2017; San Francisco.

Additional Reading

By Lisa Jo Rudy
Lisa Jo Rudy, MDiv, is a writer, advocate, author, and consultant specializing in the field of autism.