If you’ve read about weight loss recently, chances are you’ve come across green coffee bean extract. Brought into the spotlight by physician and TV show host Dr. Oz, green coffee bean extract is hailed as one of the better and safer weight-loss supplements on the market today. But did you know research has shown it to be useful in other areas of health, too?
Raw versus Roasted
Green coffee beans are the unroasted seeds of Coffea fruits (1). If dried, roasted and brewed, they become a regular cup of coffee, which itself has been shown in studies to do the body good due to its high levels of antioxidants. However, drinking a cup of coffee will not provide the same weight-loss benefits that green coffee bean extract will; it doesn’t contain enough of its active component, chlorogenic acid.
Chlorogenic acid is a phytochemical found in most fruits and, in higher concentrations, coffee beans (2)! Unfortunately, chlorogenic acid levels in coffee beans decrease during roasting. In one study, researchers found that roasting green coffee beans at 230°C for 12 minutes slashed its chlorogenic acid levels in half; roasting them for 21 minutes at 250°C reduced chlorogenic acid content to “almost trace levels”(3). So, to reap the full benefits of green coffee bean, consume it unroasted, preferably in extract form.
Chlorogenic acids inhibit amylase and glucosidase, the carbohydrate-digesting enzymes. This decreases sugar absorption, minimizes blood-sugar spikes and may lead to improved insulin sensitivity and, ultimately, fat loss over time (4).
Multiple studies have tested the efficacy of green coffee bean for weight loss. In a recent 22-week crossover study, 16 overweight adults were divided into three groups. Each group took either 1,050 mg or 700 mg of green coffee extract or placebo for six weeks. After a two-week washout period, they then switched dosages. The process was then repeated, so by the end of the 22-week period, each group had taken the high dose, low dose and placebo for six weeks. Despite no significant changes in diet, individuals lost an average of 17.6 pounds and 4.44% of their body fat. Most importantly, these decreases occurred while taking the green coffee extract, not the placebo (5).
Other researchers compared glucose absorption in 12 healthy adults who either drank normal, decaffeinated or chlorogenic acid-enriched coffee. They found a 6.9% reduction in glucose in those that drank the enriched coffee versus no effect in the other groups (6). Their second study compared weight loss results for 30 overweight adults who drank either chlorogenic acid-enriched or normal coffee. Those who drank the former lost an average of 11.9 pounds, while those who drank the latter only lost 3.7 (6). The researchers thus concluded that chlorogenic acid has “a significant effect on the absorption and utilization of glucose from the diet,” one that can reduce body mass over time (6).
Other Health Benefits
Though green coffee bean’s rise to fame was driven by its weight-loss potential, that isn’t its only use. A recent crossover study found chlorogenic acid, specifically from green coffee bean extract, reduced systolic and diastolic blood pressure in 20 adults over five weeks (7). It also significantly reduced their cortisol/cortisone ratios. This suggested an inhibition of 11bHSD1 activity, an increase of which is associated with higher risk of cardiovascular disease and obesity (7). In addition, green coffee bean’s positive effect on blood sugar levels and inhibition of glucose absorption may play a role in diabetes support (8).
Green coffee bean may also contribute to mental health. In a double-blind, crossover study, 39 participants drank the equivalent of three cups of either caffeinated coffee, decaffeinated coffee, decaffeinated coffee enhanced with chlorogenic acid or placebo. Though regular decaffeinated coffee showed no positive effect on mood, both the caffeinated and decaffeinated coffees enhanced with chlorogenic acid improved the participants’ moods and attention processes (9). Thus, chlorogenic acid may have positive behavioral effects, warranting further investigation.
When choosing a green coffee bean extract supplement, be sure to look at the label; chlorogenic acid extract should be listed as either GCA or a branded, well-researched form (1). Dr. Oz suggests finding capsules that contain at least 45% chlorogenic acid, as anything less has not been tested to demonstrate weight loss. He adds that the recommended dosage for green coffee bean is 400 mg three times a day before a meal (1). WF
1. The Dr. Oz Show, “Fact Sheet: Green Coffee Bean,” www.doctoroz.com/videos/fact-sheet-green-coffee-bean, accessed Oct. 30, 2013.
2. Examine.com, “Chlorogenic Acid,” http://examine.com/supplements/Chlorogenic+Acid, accessed Oct. 30, 2013.
3. T. Shibamato et al., “Role of Roasting Conditions in the Level of Chlorogenic Acid Content in Coffee Beans: Correlation with Coffee Acidity,” J. Agric. Food Chem. 57 (12), 5365–5369 (2009).
4. K. Chiarello-Ebner, “Hot Antioxidants of 2013,” WholeFoods Magazine, 36 (4), 24–32 (2013).
5. J.A. Vinson et al., “Randomized, Double-Blind, Placebo-Controlled, Linear Dose, Crossover Study to Evaluate The Efficacy And Safety Of A Green Coffee Bean Extract In Overweight Subjects,” Diabetes Metab. Syndr. Obes. 5: 21–27 (2013).
6. E. Thom, “The Effect of Chlorogenic Acid Enriched Coffee on Glucose Absorption in Healthy Volunteers and Its Effect on Body Mass When Used Long-term in Overweight and Obese People,” J. of Intl. Med. Research, 35 (6), 900–908 (2007).
7. E. Al-Dujaili and R. Revuelta-Iniesta, “Consumption of Ground Green Coffee Influences 11B-HSD1 Activity and Improves Blood Pressure and Body Composition in Healthy Individuals,” Endocrine Abstracts, 28, 189 (2012).
8. American Chemical Society (ACS). “New Evidence that Natural Substances in Green Coffee Beans Help Control Blood Sugar Levels,” ScienceDaily, http://www.sciencedaily.com/releases/ 2013/04/130409124741.htm, accessed Oct. 29, 2013.
9. J. Schmitt et al., “Does Coffee Enriched with Chlorogenic Acids Improve Mood and Cognition after Acute Administration in Healthy Elderly? A Pilot Study,” Psychopharmacol., 219 (3), 737–749 (2012).
Published in WholeFoods Magazine, January 2014