Link between food allergies and irritable bowel syndrome

It is not known exactly what causes irritable bowel syndrome, but a number of triggers are often associated with the symptoms. With irritable bowel syndrome (IBS), intestinal contractions needed for food digestion may be stronger and last longer than normal, causing gas, bloating and diarrhea. Conversely, weak intestinal contractions may occur, resulting in slow digestion of food and constipation.

A presentation at the recent American College of Allergy, Asthma, & Immunology (ACAAI) Annual Scientific Meeting described a study of 122 people with IBS and food allergies and 32 people with IBS and no food allergies. Those with IBS that was associated with allergies were more likely to have diarrhea as their main problem, whereas those with IBS and no allergies were more likely to have constipation as their main symptom. The presenter, Mary Tobin, MD, an allergist at the Rush University Medical Center in Chicago, reported that- in a clinical setting – if a patient’s food allergies can be determined and excluded they often find improvements to their diarrhea and abdominal pain.

In a second study reported at the ACAAI meeting, participants included 48 people who had IBS with diarrhea, 65% of whom reported having digestion problems after eating specific foods. All participants were tested to see if their skin reacted to food allergens including peanuts, tree nuts, fish, shellfish, egg, milk, cereals, meats, poultry, fruits, vegetables, and legumes.

Sixty percent of the participants had positive skin prick tests, and 17% also had allergic responses to their trigger food, such as hives, swelling, abrupt nausea and vomiting, and asthma. These findings indicate an as-yet unknown link between food allergies and IBS with diarrhea.

The American College of Allergy, Asthma & Immunology (ACAAI) 2015 Annual Scientific Meeting, was held from November 5-9, 2015, in San Antonio, USA.