Are Isolated and Complex Fiber Supplements Good Choices for Weight Management? A Systematic Review

Background: Previous trials have reported beneficial effects of isolated and complex fiber supplements in obesity treatment. However, recommending fiber supplements in obese subjects remains controversial. To the best of our knowledge, no systematic review has updated the data on the effects of fiber supplements on obesity since 2010 and the need exists for a systematic review on this topic. Accordingly, a systematic review was undertaken to summarize the efficacy of different types of fiber supplements as a complementary treatment for weight management. Methods: We searched PubMed, Scopus, Cochrane Library and Google Scholar between January 2010 to August 2016 with no language restriction. Considering the inclusion/exclusion criteria and quality assessment score, finally 17 clinical trials met the eligibility criteria and were included. Results: The present study indicated that the efficacy of various fiber supplements on losing weight is variable. Several mechanisms related to physicochemical properties of fibers such as solubility, fermentability and viscosity rates can be involved in their anti-obesity effects. Dextrin, Mannan (gum Arabic) and pectin-rich fiber (lupin kernel) with no dietary interventions indicated a reduction in body weight and energy intake, while from clinical point of view, their effects were not considerable. Conclusion: Overall, findings indicated that the efficacy of fiber supplements on obesity management is dependent on their contents and physicochemical properties. It seems that fiber supplements with no weight-loss interventions did not have considerable anti-obesity effects. However, due to limited studies on each type of fiber, findings should be declared by caution. Additional research is needed on comparison of different fiber supplements in similar conditions to clarify the best type and dosage of fiber supplement as a complementary therapy in obesity management.