Vegan versus traditional Mediterranean diet effects on cardiometabolic outcomes in women with fibromyalgia: FIBROVEG Study

Fibromyalgia (FM) is associated with adverse cardiometabolic profiles and reduced quality of life. Although plant-based dietary patterns have shown cardiovascular benefits, their effects in FM remain unclear. This randomized, parallel-arm controlled trial evaluated the effect of a vegan Mediterranean diet (VegMedDiet) compared with a traditional Mediterranean diet (MedDiet) on low-density lipoprotein cholesterol (LDL-C) and FM-related outcomes. Twenty-two women with FM were assigned to follow either a VegMedDiet (n = 11) or a MedDiet (n = 11) for 6 weeks. Diets were isocaloric and matched for macronutrient distribution. The primary outcome was change in LDL-C; secondary outcomes included other cardiometabolic markers, body composition, and FM-related symptoms and were considered exploratory. Outcomes were analyzed using linear mixed-effects models accounting for repeated measures. Compared with the MedDiet, the VegMedDiet produced greater reductions in LDL-C (estimated mean difference −21.2 mg/dL; 95% CI −38.3 to −4.08) and triglycerides (−27.4 mg/dL; 95% CI −52.1 to −2.73). Additionally, a significantly greater reduction was observed in the FIQ pain item (estimated mean difference −1.88; 95% CI −2.99 to −0.77; p = 0.002). These findings suggest that a VegMedDiet may contribute to short-term improvements in cardiometabolic risk markers and FM-related symptoms compared with a MedDiet, supporting its potential role as a dietary strategy in individuals with FM.