Self-Reported Non-Celiac Wheat Sensitivity and Other Food Sensitivities in Patients with Primary Sjögren’s Syndrome

Background: Wheat or cow’s milk intake might influence the primary Sjögren’s Syndrome (pSS) clinical manifestations. A high prevalence (20–30%) of autoimmune diseases, including pSS, has been reported in non-celiac wheat sensitivity (NCWS). This study aimed to identify the prevalence of self-reported NCWS and sensitivity/intolerance to other foods in patients with pSS, and to establish the specific clinical and immunological features of this subgroup of patients. Methods: 82 prospectively enrolled pSS patients were compared to 161 type 2 diabetes controls without rheumatological disease. The presence of a self-reported NCWS, and/or self-reported milk intolerance (SRMI), and/or multiple food sensitivity (MFS) was assessed by a validated questionnaire. Clinical and immunological features of pSS subjects, stratified according to the presence/absence of self-reported NCWS, were analyzed. Results: pSS patients had a higher frequency of self-reported NCWS (47.6% vs. 18.6%, p < 0.0001), SRMI (29.3% vs. 5.6%, p < 0.0001) and MFS (30.5% vs. 9.3% p < 0.0003) compared to controls. After the intake of wheat-containing products, 18 (21.9%) pSS patients reported the worsening of disease-specific symptoms, whereas 11 (13.4%) reported a significative clinical improvement after wheat-free diet (WFD) introduction. Moreover, 47.6% of pSS subjects complained of wheat-related gastrointestinal/extraintestinal disorders. No clinical/immunological feature differentiates pSS patients with and without self-reported NCWS, excluding a higher frequency of SRMI (39.5% vs. 11.9%, p = 0.01) and MFS (65.7% vs. 23.8%; p = 0.0004) in the former. Conclusions: This study shows a clear association between pSS and NCWS, confirming that wheat intake could be a common trigger of symptoms of both these conditions. WFD adoption seems to reduce both gastrointestinal/extraintestinal and pSS-specific symptoms in a subgroup of pSS patients, opening new possibilities for their clinical management.