The purpose of creating a green coffee extract was to produce a supplement containing a high level of and concentrated chlorogenic acid, which is believed to have various health properties including widely claimed weight loss properties.
The weight loss properties of these products usually come from the information on the products themselves, from scientific studies which are mostly biased (since they are sponsored by the industry) and from anecdotal evidence (which could also be initiated by the industry).
Green (raw) coffee beans are the best source of chlorogenic acid and the best way to obtain it is by extracting it.
Note: these products can contain caffeine, however decaffeinated types are also available.
There are other ways of obtaining chlorogenic acid but GCE supplements seem to be the best option. Brewing green beans produces an awful tasting beverage and roasting beans drastically reduces the amount of chlorogenic acid. (read more..)
Studies on the effectiveness of chlorogenic acid in weight loss
A recent systematic review from 2011 (a study that combined all of the available studies and used statistics to calculate the overall results) concluded that all studies regarding the GCE might have been industry bias, and the methodology of these studies had poor quality.
More independent and high quality studies are needed to show if GCE or chlorogenic acid are effective in weight loss. (1)
One study, for instance, which showed significant weight loss in overweight people taking GCE has been retracted by the authors with the reason that “The sponsors of the study cannot assure the validity of the data”. (2)
Two studies from 2007, with no reported conflict of interest, showed that chlorogenic acid reduces weight when consumed as an addition to instant coffee. This effect is attributed to the decrease of glucose absorption.
The first study, using 12 participants, showed that when chlorogenic acid is mixed with instant coffee it shows a 6.9% reduction in glucose absorption compared to when instant coffee is taken on its own.
The second study, using 30 overweight participants, showed that overweight people who had chlorogenic acid added to coffee, lost 3 times more weight over a 3 month period than those that had only instant coffee. (3)
More studies, with wider samples and independent from the industry, are needed.