Autism spectrum disorders (ASDs) are being diagnosed more now than in the past, mirroring the rise in food allergy diagnoses. In fact, children with ASDs are more likely to have a food allergy. These and other factors have led many to wonder if there is a connection between the two. Anecdotal evidence and research both indicate there may be some link relating ASD to food allergy and food intolerance and that the connection may be related to inflammation.
Inflammation, Allergies and Autism
Food allergy reactions are immune system reactions. The immune system is triggered, and the results are the typical symptoms of allergic reactions as well as widespread inflammation. Inflammation is normal and safe when it occurs during a normal immune response. But excessive or widespread inflammation may be harmful.
A recent study from Johns Hopkins University found that in the brains of people with an ASD, cells called microglia cells were constantly activated. These are immune cells in the brain that fight infections. When activated they cause inflammation, and in healthy brains they are not always activated. The study does not suggest this is a cause of autism, but it does make an important connection between inflammation and ASDs. This could lead to further links between ASDs and inflammatory conditions, like allergies.
Gut Inflammation, Food Allergies and ASD
Further evidence that food allergies and ASD may be related is that children with autism often have gastrointestinal symptoms. These may be related to food allergy or food intolerance. Why children with ASDs have higher rates of gastrointestinal distress and inflammation is not understood, but it is another link that connects food, allergens, inflammation and ASD.
Food Allergies Can Aggravate ASD Symptoms
Whether or not there is any causal link between the two conditions, what is certain is that having an allergic reaction can worsen many of the symptoms of ASD. Because an allergic reaction causes inflammation throughout the body, it is generally uncomfortable. This can exacerbate hyperactivity, irritability and repetitive behaviors in a child. Depending on the severity of the ASD, a child may have difficulty with or be unable to communicate discomfort, which can lead to so-called “acting out.”
A certain type of food allergy, called eosinophilic esophagitis (EoE), can be particularly aggravating for a child with an ASD. EoE is different from other food allergies in that it is a combination of immune system- and non-immune system-mediated responses. This mix causes the reaction to a food to be delayed and may result in difficulty with sleep, focus and attention, and can cause greater irritability.
Inflammation is increasingly becoming an important factor in the study of ASDs. Numerous studies now link these disorders to inflammation in various ways, from inflammation in the brain to food reactions in the gastrointestinal tract. Food allergies are also more prevalent in children with ASDs and cause inflammation. It remains to be seen exactly how these things are all connected, but what we do know is that there is some link and that each affects the other.