Green coffee extract

A 2011 review found tentative evidence that green coffee extract promotes weight loss; however, the quality of the evidence was poor.[1] This review looked at three published randomized controlled trials of green coffee extract, totaling 142 participants, and found a small effect. The review stated that more rigorous trials with longer duration were needed to assess the efficacy and safety of green coffee as a weight loss supplement.[1] Participants in the studies were instructed to restrict their diet and increase their exercise in addition to taking the supplement. One of the trials was retracted in 2014 because the accuracy of the data was unclear.[4][5] The three clinical trials reported no adverse effects; however, the review noted that two participants in an unrelated non-trial study report dropped out due to adverse events including headache and urinary tract infection.[1]

A larger 2017 review assessed the effects of chlorogenic acids, the main phenolic compounds in green coffee extract. It included studies of chlorogenic acids both as a constituent of coffee and directly as a purified extract, and suggested several beneficial effects, in particular improved glucose and lipid metabolism, as well as anti-oxidant and anti-inflammatory activity. The review noted that potential adverse effects of both short and long-term consumption had not yet been investigated thoroughly, and that the number of studies performed on humans has thus far been limited.[6]

In April and September 2012, The Dr. Oz Show featured green coffee extract, and conducted its own non-scientific study as to its efficacy. The guest on that show, Lindsey Duncan, had been fined $9 million by the Federal Trade Commission for making deceptive and unsubstantiated claims related to green coffee products promoted on The Dr. Oz Show.[7][8]

Fortune magazine reported in June 2014 that the benefits of consuming green coffee bean extract had been largely disproved by studies to date, and that green coffee extract has been the subject of Federal Trade Commission action against a Florida company and the subject of Senate hearings against misleading advertising for weight loss products.[9]

In May 2014 the Federal Trade Commission charged the Florida-based manufacturers of a product called Pure Green Coffee with deceiving consumers with false weight loss claims.[10] The FTC said that reliance on the Vinson study was deceptive since serious methodological flaws render its results unreliable.[11][12]

On June 17, 2014, the U.S. Senate sub-committee on Science, and Transportation Committee held hearings to discuss weight-loss products and consumer protection.[13] During the hearings, green coffee extract was cited often as an example of a "phony" product sold to consumers.[9] When Dr. Oz. defended his endorsement of green coffee extract and other weight loss products on his show, Senator McCaskill stated that the “scientific community is almost monolithic against you in terms of the efficacy of the three products that you call miracles.”[13] During the hearing, Dr. Oz stated "I actually do personally believe in the items I talk about on the show. I passionately study them. I recognize they don’t have the scientific muster to present as fact but nevertheless I would give my audience the advice I give my family all the time, and I have given my family these products. Specifically the ones you mentioned, then I’m comfortable with that part." He said he believes in them "as short-term crutches, and even has his family try them. But there's no long-term miracle pill out there without diet and exercise."[14]