BackgroundMetabolic syndrome is recognized as one of the most common global health issues, which may cause numerous side effects. Studies have shown the favorable effects of probiotic supplements on glycemic indices, lipid profiles, and oxidative stress status. However, the number of studies investigating the effects of food products containing probiotics and prebiotics on metabolic diseases is limited. Limited evidence also shows that products containing Lactobacillus plantarum could affect metabolic alterations in chronic diseases. No previous study evaluated the impact of synbiotic yogurt containing Lactobacillus plantarum on people with metabolic syndrome. Therefore, the current study aims to investigate the effect of the newly developed synbiotic yogurt containing Lactobacillus plantarum, Lactobacillus pentosus, and Chloromyces marcosianos yeast on the components of metabolic syndrome, oxidative stress status, and some other risk factors for cardiovascular diseases in adults with metabolic syndrome.MethodsIn this study, 44 patients with metabolic syndrome will be randomly assigned to intervention and control groups in a randomized, double-blind, controlled clinical trial. Participants in the intervention group will consume 300 g of synbiotic yogurt daily, while those in the control group will consume 300 g of regular yogurt daily for 12 weeks. Anthropometric measurements, blood pressure, and biochemical parameters will be evaluated before and after the intervention.DiscussionThe management of the metabolic syndrome presents significant clinical challenges. While probiotic supplementation for these individuals has been considered, the consumption of probiotic-rich foods has received considerably less attention.Trial registration numberIranian Registry of Clinical Trials (IRCT20220426054667N1) (2022–05-18).