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Autism and GI Disorders

Please use independent judgment and request references when considering any resource associated with diagnosis or treatment of autism or its associated medical conditions. The following information is solely for educational purposes, not medical advice. It is not a substitute for care by trained medical providers. Autism Speaks is not engaged in the practice of health care or the provision of health care advice or services. For specific advice about care and treatment, please consult your physician.

Gastrointestinal (GI) disorders are among the most common medical conditions associated with autism. These issues range from chronic constipation or diarrhea to irritable and inflammatory bowel conditions. They can affect persons of any age. But in the context of autism, they have been most studied in children.

For example, the Centers for Disease Control and Prevention (CDC) recently found that children with autism are more than 3.5 times more likely to suffer chronic diarrhea or constipation than are their normally developing peers. Other researchers have found a strong link between GI symptoms and autism severity in children. Some experts have even proposed that toxins produced by abnormal gut bacteria may trigger or worsen autism in some children.

Understandably, the pain and discomfort caused by GI symptoms can worsen behavior and even trigger regression in persons with autism spectrum disorder (ASD). This may be particularly true of nonverbal persons who have difficulty expressing their distress.

Treating GI Disorders in Those with Autism

Autism Speaks Autism Treatment Network is dedicated to enhancing the ability of pediatricians and other doctors to treat associated medical conditions including GI disorders. The ATN's GI Committee has been drafting treatment guidelines for diagnosing and treating constipation, chronic diarrhea and food allergies. (For an Autism Treatment Network clinic near you, please see our ATN directory.)

Chronic constipation: Periodic constipation is normal, but chronic constipation can be a serious condition. It is typically defined as constipation lasting two weeks or more. The abdominal pain associated with constipation can be considerable. Tell-tale behaviors can include arching the back, pressing on the belly and gritting teeth.

Causes of chronic constipation can include a restricted diet that provides insufficient fiber, certain medications and sensory or behavioral issues that interfere with regular toileting. Other contributors can include anatomic, neurological or metabolic problems or abnormal gut motility (a sluggish intestinal tract). Medical tests are needed to identify such underlying causes. Treatments can include both medical and behavioral interventions.

Behavioral management includes dietary changes (increasing fiber, eliminating constipating foods) and management of toileting behaviors (such as teaching a child to sit on the toilet after meals). Medications may include soluble fiber and laxatives such as mineral oil, magnesium hydroxide or sorbitol.

Because constipation is particularly common among children with ASD, Autism Speaks ATN GI Committee has prioritized the development and testing of its constipation guidelines, or “algorithm.” This algorithm guides pediatricians in diagnosing and treating this common condition in a step-wise manner. It also helps them determine when a child should be referred to a GI specialist.

Chronic diarrhea: As with constipation, periodic bouts of diarrhea are normal, but chronic diarrhea (two weeks or more) can be serious. Chronic diarrhea may have a number of causes including intestinal infection, immune dysfunction, inflammatory bowel diseases (Crohn’s or ulcerative colitis), irritable bowel syndrome, celiac disease (gluten intolerance), food allergies, lactose intolerance or excessive consumption of certain foods such as apple juice. In some instances, diarrhea can actually occur as a consequence of severe constipation.

Treatment depends on the cause. For instance, diarrhea due to food allergies, lactose intolerance or celiac disease is usually treated with dietary restrictions. Other times, medications or (rarely) surgery are warranted.

Gastroesophageal reflux disease (GERD): GERD results when the muscle between the stomach and esophagus (food pipe) is lax. This allows partially digested food or liquid mixed with stomach acid to move up out of the stomach. Red flags include throat discomfort and/or feelings of “heart burn.” However children sometimes experience GERD pain in atypical ways, and nonverbal persons can have difficulty communicating their distress.

In persons with autism, GERD pain may result in increased self-injury or other challenging behaviors. It can be helpful to note if such behaviors are triggered or made worse when the individual is lying down (a position that can worsen reflux). Other telltale signs can include unusual body postures or behaviors such as straining the neck, pushing out the jaw or tapping the throat. Other signs may include hoarseness, chronic sore throat, cough or heartburn, dental erosions, food refusal or disturbed sleep.

Such issues should be discussed with a doctor, who can refer to a GI specialist if needed. Helpful behavioral modifications include elevating the head during sleep, avoiding food near bedtime, eating smaller meals and avoiding foods that tend to trigger symptoms. GERD-easing medications include antacids, histamine-2 blockers (Pepcid, Zantac, etc) and protein-pump inhibitors (Nexium, Priolosec, etc). When GERD is severe or chronic, your physician may perform tests to identify acid levels and tissue damage in the esophagus.  

Casein- and Gluten-free Diets

Many parents of children with ASDs report that behavior improves when their children eat a diet free of the proteins gluten and casein. Gluten is found primarily in wheat, barley and rye; casein, in dairy products. In 2010, clinicians within Autism Speaks Autism Treatment Network investigated the use of casein- and gluten-free diets and found insufficient evidence of clear benefit. However, this was a relatively small study, and it is possible that subgroups of children may benefit. The authors called for more studies to be conducted, and these are now underway.

Meanwhile, it’s reasonable to ask what harm could result from trying a casein-gluten-free diet. Certainly, dietary changes can be worth investigating and trying, especially if there are other family members that have had difficulties tolerating gluten and/or casein in foods. And as mentioned, many parents report improvements in behavior. However, until more clinical studies are completed and more evidence of safety and benefit is available, parents who place their child on such a restricted diet need to take extra steps to ensure they do so in a safe and reliable manner.

Many parents have reported that probiotics ("good" bacteria) help ease gastrointestinal distress in their children. Autism Speaks is funding research in this new field of study. Please also see "Guidance on Probiotics."

Pediatric gastroenterologist Kent Williams, of our ATN center at Nationwide Children’s Hospital, in Columbus, Ohio, offers the following advice:

1. Consult with a dietary counselor such as a nutritionist or dietician. Although it’s easy to find casein-gluten-free dietary plans on the Internet, few lay people – or physicians – have the experience and knowledge to determine whether a restrictive diet is providing all the necessary nutritional requirements. This is particularly important for supporting normal growth and development in children. Keep in mind that foods containing gluten and casein are major sources of protein as well as essential vitamins and minerals such as vitamin D, calcium and zinc.

2. Bring the nutritionist or dietician a 3- to 5-day dietary history (writing down what was eaten and how much) and have this reviewed to determine whether there is a risk for nutritional deficiency. The nutritionist or dietician can then work with you to add foods or supplements that address potential gaps in nutrition.

3. Set up a reliable way to measure your or your child’s response. This should start before the diet is begun, with a list of the specific symptoms and/or behaviors that you would like to improve. In the case of a child, examples might include angry outbursts, inability to sit quietly during class, problems sleeping at night or refusal to speak with others.

4. Recruit teachers, therapists, babysitters, and others outside the family to help you objectively monitor these targeted behaviors and verify your perception of changes. If you reach a consensus that improvements are occurring, continuing the diet may be worth the cost and effort. 

Remember that improvements may be due to the removal of just one of these proteins (gluten or casein) from the diet. Some parents report improvement with a casein-free diet, and others report improvements with a gluten-free diet. In fact, behavioral changes may be due to dietary changes other than the removal of casein or gluten. For example, the improvement might be due to the fact that the new diet replaces processed foods high in sugar and fat with healthier foods such as whole grain rice, fruits, and vegetables.

These alternative explanations are important to consider because a strict casein-gluten free diet requires hard work and can be costly. For example, it may be difficult for you or your child to eat from the menus in a restaurant or school cafeteria. Birthday parties present another challenge. You’ll likely be faced with the task of sending or bringing special meals and treats whenever you or your child eats away from home. 

Autism Speaks Research on GI Disorders

Autism Speaks’ ATN continues to support clinical research and best-practices guidelines on nutritional and gastrointestinal issues associated with autism through the HRSA-funded Autism Intervention Network for Physical Health. Thanks to donor support, Autism Speaks has funded and is funding more than a score of studies into the causes, diagnosis and treatment of these distressing conditions. (Follow this link to learn more.) Here are some highlights of important recent findings:

* In 2011, researchers supported by Autism Speaks reported that the GI activity of some children with autism differs from that of other children in two key ways: Their intestinal cells show abnormalities in how they break down and transport carbohydrates; and their intestines are home to abnormal amounts of certain digestive bacteria. (Bacteria play an important role in normal digestion. But abnormal levels of certain bacteria have been associated with digestive problems and intestinal inflammation.)

The two findings may be related. Alterations in how intestinal cells break down carbohydrates can affect the amount and type of nutrients that these cells provide to intestinal bacteria. This, in turn, may alter the makeup of the intestine’s normal community of digestive bacteria – with ill results.

These findings may also explain why parents of some children with autism report that special diets and probiotics (nutritional supplements containing “good” bacteria) improve not only their children’s digestion but also their behavior. However, further study is needed as their findings were based on tissue samples from a relatively small number of children (15 with autism and 7 with typical development).

* Also in 2011, a clinical study performed at one of our ATN clinics clearly refuted the claim by some physicians that parents may be over-reporting or overly concerned about GI problems in children with autism. This study found high agreement – more than 90 percent – between parent reports of GI symptoms and evaluations performed by gastroenterologists. Also contrary to some popular thought, the children’s diet and medications did not significantly contribute to their GI distress.

Overall constipation was the most common GI diagnosis in this study. It occurred in 85 percent of children with both autism and GI disorder and was most likely to occur in children who were younger, nonverbal and/or had significant social difficulties. Indeed, the researchers found a six-fold increase in communication disturbances in the group of children who had both ASD and GI disorder, compared to children with ASD only. These findings highlight the need for healthcare providers to be vigilant in detecting and treating GI symptoms in children on the spectrum. This is particularly important in the care of nonverbal children who can’t describe their distress.

* Currently in the works is an exciting new research project examining the biological mechanisms of GI disorders in ASD. The research will include clinical testing of a new probiotic therapy that has shown promise in restoring GI function. This innovative research was made possible by a Suzanne and Bob Wright Trailblazer Award.

To explore more Autism Speaks donor-funded studies on gastrointestinal issues, click here. For related Autism Speaks news stories and blogs, follow these links: Tummy Troubles; How Helpful Is the Gluten-Casein Free Diet?; New Insight into Autism and Intestinal Problems; Autism and Associated Medical Conditions (CDC report)