Plant extracts with appetite suppressing properties for body weight control: a systematic review of double blind randomized controlled clinical trials

Abstract

Overview: As obesity has reached epidemic proportions, the management of this global disease is of clinical importance. The availability and popularity of natural dietary supplements for the treatment of obesity has risen dramatically in recent years.

Aims: The aim of this paper was to assess the current evidence of commonly available natural supplements used to suppress appetite for obesity control and management in humans using a systematic search of clinical trials meeting an acceptable standard of evidence.

Methods: The electronic databases PubMed, Web of Science, Google Scholar, ScienceDirect, and MEDLINE with full text (via EBSCOHost) were accessed during late 2012 for randomized controlled clinical trials (RCTs) using natural plant extracts as interventions to treat obesity through appetite regulation. A quality analysis using a purpose-designed scale and an estimation of effect size, where data were available, was also calculated. The inclusion criteria included the following: sample participants classified as overweight or obese adults (aged 18-65 years), randomized, double blind, controlled design, suitable placebo/control intervention, sample size >20, duration of intervention >2 weeks, have measurable outcomes on appetite or food intake and anthropometry, and full paper in English.

Results: There were 14 studies that met the inclusion criteria. The findings from published double blind RCTs revealed mostly inconclusive evidence that plant extracts are effective in reducing body weight through appetite suppression. Caralluma fimbriata extract and a combination supplement containing Garcinia cambogia plus Gymnema sylvestre were the only exceptions.

Conclusion: According to the findings from this systematic review, the evidence is not convincing in demonstrating that most dietary supplements used as appetite suppressants for weight loss in the treatment of obesity are effective and safe. A balance between conclusive findings by double blind RCTs and advertisement is required to avoid safety concerns and dissatisfaction from consumers.

Keywords: Appetite; Body weight; Food intake; Plant extracts.