Efficacy of a gluten-free diet in reducing the widespread pain index and symptom severity scale in patients affected by fibromyalgia

Objective. Dietary interventions to improve fibromyalgia (FM) symptoms reported conflicting results. This study aimed to treat FM patients with a gluten-free diet (GFD), alternated with a non-restricted gluten-containing diet, followed by a rechallenge of the GFD. Methods. Twenty postmenopausal women with FM and no history of celiac disease participated. A GFD was as-signed for 6 months. This was followed by 3 months of a non-restricted gluten-containing diet and then a new GFD for another 6 months. At each visit, the widespread pain index (WPI) and the symptom severity scale (SS) scores were evaluated. Results. The mean age of the patients enrolled was 53.9±10 years. None of the patients had a diagnosis of irritable bowel disease, although they reported vague gastrointestinal symptoms. After 6 months of a GFD, a statistically significant reduction was observed for the WPI (10.3±1.8 vs 7.7±1.4; p<0.0001) and the SS scale (6.4±1.8 vs 4.15±1.6; p=0.0002). The D percentage reduction of the WPI after 6 months of GFD was-24%±9%, while for the SS scale, it was-36%±21%. The following reintroduction of a gluten-containing diet brought about a statistically significant rise in the absolute SS scale and WPI, as well as a D modification of the WPI (21%±13%) and of the SS scale (74%±90%). The rechallenge of the GFD showed a significant improvement in absolute and D WPI (-24%±7%) and SS (-36%±11%). No modifications to the body mass index were found. Conclusions. A GFD improved FM symptoms evaluated with WPI and SS. This was confirmed for the first time, also with a rechallenge of the GFD that followed a non-restricted gluten-containing diet.