Beneficial Effects of a Low-Nickel Diet on Relapsing IBS-Like and Extraintestinal Symptoms of Celiac Patients during a Proper Gluten-Free Diet: Nickel Allergic Contact Mucositis in Suspected Non-Responsive Celiac Disease Original paper

What was studied?

The study investigated the prevalence and effects of nickel allergic contact mucositis (Ni ACM) in celiac disease (CD) patients who were on a proper gluten-free diet (GFD) but experienced a relapse of Irritable Bowel Syndrome (IBS)-like gastrointestinal and extraintestinal symptoms. The main goal was to determine whether nickel-rich foods in a gluten-free diet could trigger these symptoms and to evaluate the impact of a low-nickel diet (LNiD) on symptom reduction in these patients. This pilot study also explored the use of the nickel oral mucosa patch test (Ni omPT) to diagnose nickel sensitivity in these patients.

Who was studied?

The study involved 102 consecutive adult celiac disease patients (74 females, 28 males, mean age 42.3 ± 7.4 years) who had been on a gluten-free diet for at least 12 months and were in serological and histological remission of their disease. These patients were selected because they reported relapsing or persisting gastrointestinal and extraintestinal symptoms despite proper adherence to a GFD. After exclusions based on comorbid conditions like lactose intolerance and Helicobacter pylori infection, 20 patients (all female, age 23–65 years) were included in the final analysis.

What were the most important findings?

In a cohort of 20 patients with persistent symptoms despite adherence to a gluten-free diet (GFD), all tested positive for nickel sensitivity via the nickel oral mucosa patch test (Ni omPT), confirming a diagnosis of nickel allergic contact mucositis (Ni ACM). Following prolonged GFD, 83.3% of patients experienced a relapse of symptoms, including abdominal pain, bloating, loose stools, and fatigue, coinciding with high dietary nickel intake from nickel-rich gluten-free foods such as corn. Implementing a low-nickel diet (LNiD) for three months improved 83.4% of total symptoms, with 41.7% reaching statistical significance. Notably, 80% of gastrointestinal and 88.9% of extraintestinal symptoms improved, including significant relief from abdominal pain, swelling, fatigue, and dermatitis. Combining LNiD with GFD restored patients’ well-being to levels comparable to those previously achieved by GFD alone, strongly implicating nickel sensitivity as the primary driver of symptom relapse.

What are thegreatest implications of this study?

This study provides strong evidence that nickel-rich foods in a gluten-free diet can trigger or exacerbate IBS-like gastrointestinal and extraintestinal symptoms in a subset of celiac disease patients, even when the disease is in serological and histological remission. The findings highlight the importance of nickel sensitivity (Ni ACM) in the pathogenesis of these relapsing symptoms, suggesting that a low-nickel diet (LNiD) can be a valuable intervention to improve patient outcomes. The use of the nickel oral mucosa patch test (Ni omPT) was also validated as a reliable diagnostic tool for identifying nickel-sensitive patients.

Clinically, these results imply that gastroenterologists should consider nickel sensitivity as a differential diagnosis in celiac patients who are non-responsive to a GFD and continue to experience symptoms. The integration of a low-nickel dietary approach alongside the GFD may become an essential part of managing non-responsive celiac disease with overlapping IBS-like symptoms. Further large-scale studies are needed to confirm these findings and refine dietary guidelines for managing nickel sensitivity in this population.