Background: Metabolic syndrome, a concurrence of overweight and abdominal fat distribution, disturbed glucose and insulin metabolism, mild dyslipidemia and hypertension is among the most important issues that man deals with, in today's world. Probiotics are live microorganisms which, when administered in adequate amounts, can confer a health benefit on the host. The aim of the present study was to review the clinical evidence available regarding the role of probiotics in improvement of disorders associated with metabolic syndrome.

Materials and Methods: In this research, clinical trials performed between 2000-2014 were searched in two databases, Pubmed and ScienceDirect. In both databases “Probiotics”, “metabolic syndrome” and each of its elements were used as the key words.

Results: Probiotics may reduce body weight through manipulating the gut flora. Through reducing inflammation and immune-regulation, probiotics decrease insulin resistance. They also improve lipid profile through reducing cholesterol absorption and producing short chain fatty acids, as well as deconjugating bile acids and converting cholesterol to coprostanol. Moreover, probiotics have been suggested to have a hypotensive effect through release of angiotensin-converting enzyme inhibitory peptides, through proteolytic action. 

Conclusion: Although some clinical trials have failed to obtain beneficial effects of probiotics on metabolic syndrome related situations, a majority of the studies have shown positive results for these microorganisms in this regard. Thus, probiotics can be looked upon as a novel approach when either prevention or alleviation of metabolic syndrome is aimed.