Garcinia use in weight loss supplements questioned by meta-analysis
The study, published in the Journal of Obesity systematically reviewed evidence for the efficacy of Garcinia extract – hydroxycitric acid (HCA) – as a weight reduction agent, using data from 12 randomised clinical trials (RCTs).
The researchers, led by Professor Edzard Ernst of Peninsula Medical School, UK, reported that the evidence from RCTs “suggests that Garcinia extracts/HCA generate weight loss on the short term. However, the magnitude of this effect is small, is no longer statistically significant when only rigorous RCTs are considered, and its clinical relevance seems questionable.”
“Our systematic review corroborates the findings from a previous systematic review of weight loss supplements, which reported that the weight reducing effects of most dietary supplements is not convincing,” wrote Ernst and his team.
Ernst and his colleagues noted that the prevalence of overweight and obesity has increased over the last decade, adding that current measures to reduce weight “have not been able to stem the tide.”
They explained that a wide variety of weight management strategies are available, some involving the use of dietary supplements marketed as slimming aids.
One such supplement is Garcinia extract, a derivative of citric acid that can be found in plant species native to South Asia including Garcinia cambogia, Garcinia indica, and Garcinia atroviridis.
The review team noted animal studies have suggested that HCA can aid weight loss, adding that human trials involving the use of HCA as a weight loss supplement have been carried out.
“The primary objective of this systematic review was to examine the efficacy of HCA in reducing body weight in humans, using data from randomised clinical trials,” said the reviewers.
Ernst and his co-workers reviewed only randomised, double-blind, placebo-controlled studies that investigated the efficacy of oral HCA or any of its salts for weight reduction in obese or overweight humans.
The authors explained that 12 randomised clinical trials including a total of 706 participants met the inclusion criteria and were included in this systematic review.
A meta-analysis of the pooled results from the RCTs revealed a statistically significant difference in body weight between the HCA and placebo groups, noted the authors. However they said that the average effect size was small – constituting a reduction of 0.88kg on average, or a 1% loss in body weight in the HCA group compared with placebo.
Ernst said noted that the overall meta-analysis revealed a small difference in change in body weight between the HCA and placebo groups, but stated that the effect “is of borderline statistical significance and is no longer significant on the basis of a sensitivity analysis of rigorous RCTs.”
“Arguably the overall effect size is also too small to be of clinical relevance,” said the researchers, noting that the results of their review “should be interpreted with caution.”
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Source: Journal of Obesity
Volume 2011, Article ID 509038, 9 pages , doi:10.1155/2011/509038
“The Use of Garcinia Extract (Hydroxycitric Acid) as a Weight loss Supplement: A Systematic Review and Meta-Analysis of Randomised Clinical Trials”
Authors: I. Onakpoya, S.K. Hung, R. Perry, B. Wider, E. Ernst