Study: Food allergies can trigger immune system reactions in the stomach and small intestine

A new Northwestern Medicine study published in the Journal of Allergy and Clinical Immunology and in collaboration with The Consortium of Eosinophilic Gastrointestinal Researchers was the first to show that food allergies can trigger immune system reactions in the stomach and small intestine, causing symptoms like pain, nausea, vomiting, early satiety, weight loss and diarrhea. During the study, 15 adult patients ages 18 to 65 who suffered from eosinophilic gastritis or gastroenteritis achieved complete elimination of their gut inflammation after six weeks of dietary therapy. When their trigger foods were reintroduced, patients suffered from reactivation of their disease, giving new medical insights into the role food allergies play in a patient’s overall health and quality of life.

For many years, physicians have known that white blood cells called eosinophils can build up in the lining of the esophagus, the muscular tube that connects the mouth to the stomach. That cell buildup can cause inflammation that leads to difficulty swallowing and esophageal pain. The same white blood cell buildup can occur in the rest of the gastrointestinal tract, but these disorders are significantly more rare.

“This study is exciting for patients who suffer from these rare disorders, which previously had to be treated with medications called steroids that can have other harmful effects on the body,” said Nirmala Gonsalves, MD, lead author of the study and a gastroenterologist at Northwestern Memorial Hospital. “It shows that a special diet can heal severe inflammation in the lining of the stomach and intestine without involving medication. Once the patient’s gut is healed, we can introduce specific foods to try and identify which ones are triggering the disease. In the end, this process of food reintroduction can make the diet less restrictive and improve quality of life.”

Patients who participated in the first part of the trial used an elemental diet – liquid nutrients that are easily absorbed – as their sole source of nutrition for six weeks. When tests determined they achieved complete remission of their disease, the Digestive Health Center team at Northwestern Memorial Hospital carefully reintroduced foods that are likely to cause allergic reactions, and then tested for inflammation. While each patient had different results, common food allergens known to be triggers in eosinophilic gastrointestinal disease include cow’s milk, wheat, eggs, soy, nuts and seafood.

“This study is the first to show that food allergens are triggering eosinophilic disease in the stomach and small intestine of patients,” Dr. Gonsalves said. “This study also showed that after patients were on this diet, they had improvement in endoscopic findings, symptoms, and dysregulation of important genes thought to be involved in this condition. For patients who suffer from eosinophilic gastritis or eosinophilic duodenitis, this new approach can be life-altering, as it will allow patients natural alternatives to steroid therapy while helping to heal their inflammation.”