The science to support the efficacy of green coffee extracts for weight loss is ‘promising’, but longer and ‘more rigorous’ trials are needed to support the potential, says a new systematic review and meta-analysis.
Analysis of three randomised clinical trials (RCTs) providing data from 142 participants met the reviewers’ strict inclusion criteria, with the overall results being described as “promising”.
However, according to findings published in Gastroenterology Research and Practice , the studies analysed for the review were all of “poor methodological quality”.
As obesity rates continue to rise, the opportunities for scientifically-substantiated weight management food products are impressive. Green coffee extracts are already available commercially, like Naturex’s Svetol, which is extracted from decaffeinated green coffee. The proposed mechanism of action is that it inhibits the activity of glucose-6-phosphatase, which is responsible for the release of glucose stored in the liver into general circulation. This means that glucose is instead drawn from deposits in adipose tissue, stimulating weight loss.
The new scientific paper, published online ahead of print in Gastroenterology Research and Practice, identified five relevant trials of green coffee extracts for weight management, with three deemed eligible for the meta-analysis.
According to the findings of Igho Onakpoya, Rohini Terry, and Edzard Ernst from Complementary Medicine, Peninsula Medical School at the University of Exeter in the UK, a “significant difference in body weight in green coffee extract [was observed] compared with placebo”.
Specifically, people receiving the green coffee extracts experienced an average of 2.47 kg of body weight loss more than the placebo group.
“The evidence from RCTs seems to indicate that the intake of GCE can promote weight loss,” stated the Exeter-based scientists. “However, several caveats exist. The size of the effect is small, and the clinical relevance of this effect is uncertain. More rigorous trials with longer duration are needed to assess the efficacy and safety of GCE as a weight loss supplement,” they concluded.
The review was described as “interesting” by Benjamin Voiry, NAT life Business manager at Naturex, “as it helps to consolidate a vast amount of knowledge”.
“In any case, it is important to look at all studies, to enable us to assist industrial customers, to successfully create weight loss products, in terms of ingredients characteristics, dosage per day and recommendation of consumption,” he added. “With Svetol, we manage the product from the extraction to scientific research.”
Voiry added that the company is also following the health claim evaluation being made by EFSA. “Naturex submitted a generic health claim for weight loss for a green coffee bean extract with Svetol specific characteristics.
“This means that our European customers can still communicate on their products if they are using Svetol. US customers are using studies made on Svetol to communicate about their weight loss products,” he said.
Source: Gastroenterology Research and Practice
Published online ahead of print, doi:10.1155/2011/382852
“The use of green coffee extract as a weight loss supplement: a systematic review and meta-analysis of randomised clinical trials”
Authors: I. Onakpoya, R. Terry, E. Ernst