Introduction Metabolic syndrome comprises a set of risk factors for chronic diseases including abdominal obesity, increased fasting blood glucose (FBG), altered lipid profile and elevated blood pressure (BP). Due to high prevalence of metabolic syndrome and its complications in the military personnel, the relevant problems should be identified and controlled. Therefore, the present study was conducted to determine the effect of synbiotic supplements on the components of metabolic syndrome in the military personnel with metabolic syndrome.

Methodology Sixty military personnel with metabolic syndrome were included in this double-blind randomised controlled clinical trial. During the intervention, they were asked to consume one capsule of synbiotic supplement or placebo per day for 8 weeks. Body Mass Index (BMI), waist circumference, BP, FBG and lipid profile were measured before and after the intervention.

Results The results of the study showed that the synbiotic supplementation had a large significant adjusted effect on the BMI (Cohen’s d=0.82 (95% CI 0.29 to 1.34)). It also had a medium significant adjusted effect on the FBG (Cohen’s d=0.52 (95% CI 0.004 to 1.03)) as well as triglyceride (Cohen’s d=0.65 (95% CI 0.13 to 1.17)).

Conclusion Findings of the study revealed that synbiotic supplementation may lead to a significant improvement in the BMI, triglyceride and FBG levels in the military personnel. Thus, consumption of synbiotic supplements is recommended as an adjuvant therapy in the military personnel with metabolic syndrome.