Digestive disorders are simply awful. Chronic constipation and diarrhea are painful, anxiety-provoking and harm the quality of life for anyone who suffers from them. Autism spectrum disorder (ASD), which is characterized by impairment in social interaction and communication, makes life challenging for the children who have it and for their family members who love them. Can you imagine how difficult it would be to have both disorders at the same time? Unfortunately, children with ASD are four times more likely to suffer from chronic digestive disorders than their peers. Why this might be is an interesting puzzle and the answer could lead to potential treatments for both health concerns.
Autistic Spectrum Disorder (ASD) is a diagnostic term first introduced in the DSM-V that includes a range of related neurodevelopmental disorders, which previously would have been diagnosed (under the prior version of the DSM (the DSM-IV-TR)) as autism, Asperger syndrome, pervasive development disorder not otherwise specified (PDD-NOS), childhood disintegrative disorder, or Rett syndrome. Medical science does not currently understand what causes ASD, although the current state of the research suggests that there are many possible causes / triggers to the disorder in addition to the genetic component that has been observed.
Children with Autism Spectrum Disorder (ASD) suffer from chronic digestive problems at much higher rate than their unaffected siblings and up to a magnitude of four times that of their peers. Constipation and diarrhea are the most common digestive symptoms that ASD children suffer from. This differential is even more pronounced in children with significant impairment from the ASD (what would previously have been diagnosed as full blown Autism).
Imagine how debilitating chronic digestive problems could be to a child with Autistic Spectrum Disorder. ASD is characterized by difficulties with verbal communication. A child with ASD may not have the vocabulary to tell his parents or care givers that he is experiencing pain or have the ability to explain what is wrong. This frustration and discomfort may in turn cause the ASD symptoms to worsen. Over time, GI symptoms may continue to increase without appropriate medical or dietary intervention, creating a vicious cycle of pain and acting out. Understandably, this ongoing physical discomfort may also affect his ability to focus on the therapies targeted at treating the ASD and may decrease his concentration at school. This is a devastating setback for those who work so hard to overcome the effects of ASD.
Non-verbal Cues of Distress
Hence it becomes critically important to be on the lookout for signs digestive problems in children with ASD.
One non-verbal sign of gastrointestinal distress, in addition to the obvious ones of diarrhea or clearly impacted stool, is a distended stomach. Clutching the abdominal area or arching the back can be other indicators of GI discomfort.
Unfortunately, according to pediatric gastroenterologist Dr. Barbara McElhanon, MD at Children’s Healthcare of Atlanta and assistant professor of pediatrics at Emory University School of Medicine, “In many cases, the only indication of a possible GI problem in autism may be the emergence or escalation of problem behaviors, such as self-injury, aggression, or irritability, that cannot be otherwise explained.”
What is the Cause of the GI / ASD Connection?
Medical researchers are still puzzling over the connection between digestive problems and ASD. No cause and effect relationship between the two has been proven. Experts are not sure whether the GI disorders may somehow be causing the behavioral issues or if in fact the behavioral issues associated with ASD are triggering the digestive issues. Perhaps some underlying factor or pathology is causing both. The triggering effect may also go both ways with the GI problems causing ASD behavior problems and then the behavior problems further exacerbating the digestive problems.
Eating Patterns
Disordered eating habits may be one explanation for the link.
It’s not uncommon for children with ASD to have problems with breast feeding as infants. The microbes transferred from mother to child during nursing are very important. They actually help the gastrointestinal system to develop and protect the digestive tract from unhealthy microbes and toxins that get digested. Perhaps this early behavioral problem may be causing some of the later GI problems due to unsufficient exposure to the beneficial probiotics contained in the mother’s milk.
Children with ASD are often extremely picky eaters, extremely selective about what they will eat. The sensory integration issues that often go along with ASD, characterized by extreme sensitivity to sensory stimulations such as taste, texture and smell, can contribute to the disordered eating. Some parents report that their affected child will eat as few as five foods.
An extremely limited diet can lead to nutrient and enzyme deficiencies, which then can affect the body’s ability to effectively digest certain types of food. Studies have been conflicting as to whether children with ASD as a whole have measurably lower levels of nutrient intake than the population of children generally. Often the diets of extremely picky eaters are deficient in fiber, which can also cause GI disturbances, particularly constipation. Unfortunately, the extreme limitations in diet that are characteristic of ASD often persist long after early childhood.
Even though unbalanced eating is clearly a factor in digestive issues for ASD children, they are unlikely to be the sole or even primary cause. As mentioned, it is the children who are most severely affected by ASD who also tend to most incidences of chronic digestive issues. Yet extreme picky eating can affect children at all ends of the ASD spectrum, not only those most significant cases of it. It would be interesting to see a study examining whether children on the ASD who are not picky / selective eaters are affected by GI issues at the same rate as those who are.
Unhealthy Mix of Gut Microbes
The mix of gut bacteria that a child with ASD has may create digestive problems.
We all have beneficial microbes living in our bodies. In fact the microbes outnumber human cells by 10 to 1. The microbes found in the digestive tract assist with digestion. They help to release enzymes and nutrients from the food. They affect metabolism, impacting human weight. Importantly, they help to train the immune system and fight off dangerous microbes and toxins.
Children with ASD are more likely than children without it to have an unhealthy mix of microbes in the digestive tract (dysbiosis). The result of the dysbiosis is that they may not have the diversity of microbes typically seen in a healthy child, or they have more unhealthy microbes or fewer of the beneficial, health promoting ones. Having a wide variety of microbes (high diversity) is associated with health.
Without a healthy mix of microbes living in the digestive tract, the digestive process may be disrupted. There may be behavioral effects from the dysbiosis as well.
In children with regressive autism (where a child appears to be developing normally, but then starts displaying autistic symptoms and losing developmental milestone (such as speech) she had previously attained) , gut dysbiosis is particularly common.
Interestingly, in a study that examined the microbiomes of both neurotypical children and children with ASD, it was found that a lack of diversity in the gut microbiome was more closely associated with the autistic behaviors than with the severity of the GI problems. This seems to imply that a lack of diversity of the microbiome is more closely associated with the Autism Spectrum Disorder itself than it is with the GI problems that often seen with ASD. And to take it one step further, this could be interpreted as meaning that there is a causative relationship between a disordered gut microbiome and ASD. Perhaps gut dysbiosis is one cause of autism.
If gut dysbiosis is somehow triggering ASD, this would also provide an explanation for the high rates of GI problems seen in children with ASD as gut dysbiosis can also cause GI disturbances in many cases. However, gut dysbiosis has not yet been proven as a cause of ASD, although it is clearly a fertile area for ongoing medical exploration, some of which is currently underway.
Decrease Digestive Symptoms by Improving Gut Health
Anecdotally, many parents report that giving their child with ASD probiotics provides significant relief from their digestive difficulties. Several prominent gastroenterologists recommend supplementation with probiotics for GI patients with ASD.
Taking steps to improve the health of the gut microbiome, such as: taking probiotics; eating a probiotic and prebiotic rich diet containing fermented foods; avoiding unnecessary antibiotics; and limiting alcohol and processed foods have been shown to be helpful with a variety of digestive disorders, including traveler’s diarrhea and food poisoning, antibiotic induced diarrhea, Inflammatory Bowel Disease (IBD), Irritable Bowel Syndrome (IBS).
A Caltech study published in 2013 showed that treating mice with ASD-like symptoms improved gastrointestinal abnormalities in the mice (as well as some of their ASD-like symptoms). This science is very compelling and promising. Unfortunately, however, animal studies do not always translate into results in humans.
Since providing probiotics (through fermented food and supplementation) as well as taking other measures to improve the health of the gut microbiome has been shown to provide relief for a wide range of digestive problems, across populations, there is no reason to think that they cannot have the same effect in the ASD population. Probiotics can treat diarrhea and reduce constipation. Furthermore, given that so many children with ASD are known to have disruptions to a healthy gut microbiome, focusing on restoring balance to the gut microbiome makes a lot of sense.
A diet rich in probiotics and prebiotics is healthy for all of us and it provides very high-levels of healthy and active beneficial microbes. Other than if there is a food allergy to one of them, there should be no downside to eating such foods and they may well provide relief from the GI discomfort. However, the food selectivity often found in children with ASD may make it difficult to get many of these foods into the child’s diet in any real quantity.
Taking probiotic supplements may provide relief from digestive disruptions. It is important, though, to be mindful about taking probiotics indiscriminately. “Probiotics” is a very broad term, encompassing thousands of bacteria and yeasts that provide beneficial effects to humans. Not every probiotic organism has the same effect and taking a probiotic without knowing what it does in the human body can be ineffective and wasteful at best, or actually harmful at worst. Also, depending on the type of dysbiosis that may be present, certain particular probiotics will be more beneficial than others. Be sure to coordinate any attempts at supplementation with a gastroenterologist to maximize the chance for success. Choose a good quality probiotic supplement if you choose to try this.
Treating the Gut may Decrease Behavioral Symptoms in Children with ASD Suffering from Digestive Disorders
When the child’s GI discomfort is relieved, often the ASD symptoms improve, according to many parents and care providers. The child is better able to participate in her ASD-focused therapies and better able to focus in school. Quality of life is therefore improved for the whole family.
Some experts in the field, supported by anecdotal reports and the mouse study referenced above (that showed a reduction in ASD symptoms in mice treated with high levels of probiotics), believe that the ASD symptoms improve, not just because the GI discomfort has been alleviated, but because the beneficial microbes are somehow directly impacting the nervous system and improving the ASD behaviors themselves.
Given the strong and well-documented connection between the gut and the brain via the Vagus nerve, this is certainly possible. Our gut microbes have already been shown to impact human behavior – as seen in how they affect appetite, anxiety and depression.
In Conclusion
ASD is not caused by one factor, but instead seems to be influence by a variety of genetic and environmental triggers.
However, there is clearly a gut-ASD connection that deserves further study. Given the increasing numbers of children affected by this disorder each year, studying potential therapeutic interventions should be a top public health priority.
Happily, many experts in the field are already actively studying the connection between ASD and the microbes in the gut, hoping it will lead to a better understanding of a potential cause of the disease as well as leading to promising new courses of treatment.
