by Jeff S. Volek, Ph.D., R.D.
Lately there has been a lot of media “buzz” about green coffee extract and how it can help you lose weight. So what’s the real story? Does it work? If it does, how does it work? What’s the difference between green coffee and regular coffee? Since my lab has conducted so many weight loss studies, I decided to review the latest research to help separate fact from fiction. How it all started
Researchers found that heavy coffee drinkers had a reduced risk for Type 2 diabetes. When investigating why, they discovered that chlorogenic acids and related compounds present in small amounts in regular coffee were likely the beneficial components. Unfortunately, the coffee bean roasting process degrades most of the valuable chlorogenic acids. However, unroasted green coffee beans are loaded with chlorogenic acids. It was hypothesized that perhaps an extract of green coffee beans would be a better source of chlorogenic acid. This would allow you to avoid caffeine and any other unwanted constituents of coffee. Chlorogenic acids — the main active
Chlorogenic acids are known to activate a spectrum of antioxidant genes that protect against oxidative stress. A study of those consuming coffee that was enriched with 200 mg of green coffee extract resulted in a significant decrease in blood pressure, and a decrease in glucose absorption in humans.
Chlorogenic acid is metabolized to ferulic acid in the liver. Ferulic acid has been shown in independent studies to be an effective treatment for high blood pressure. Ferulic acid also potentiates the action of nitric oxide and improves dilation of blood vessels. This effect may be due to inhibition of carbohydrate digesting enzymes in the gut and is believed to play a major role in reducing body weight and body fat. Average weight loss of 5 pounds
A meta-analysis of 142 individuals showed an average weight loss that was 5.5 pounds greater than a placebo group when taking 180-200 mg a day of green coffee extract.
Another study not included in the meta-analysis provides further evidence in support of a modest effect on weight loss. Overweight men and women were supplemented with placebo, low dose, and a high dose of green coffee extract. Each subject received all three treatments for 6 weeks each with a two week washout period in between. Subjects gained 0.7 pounds of body weight during the placebo period, but lost 3.4 pounds during low dose (700 mg/day) period, and lost 4.5 pounds during the high dose (1,050 mg/day) green coffee extract period. No significant side effects were reported in this study, or in any of the other human trials. 11 pound weight loss in 60 days
In another series of studies, French researchers studied the pharmacokinetic profile after ingestion of green coffee extract. Subjects twice a day consumed 200 mg of decaffeinated green coffee extract containing greater than 45% chlorogenic acids. The study indicated that the extract positively influenced the test subjects glucose metabolism and suggested to the researchers that green coffee bean extract could have an effect on weight management.
A second study was conducted by the same researchers to test their theory using the same amount of green coffee extract (200 mg 2x/day) with meals over a 60 day period. They found a significant reduction in weight of 11 pounds (5.7%) in the green coffee extract group. This was approximately twice the amount of weight loss in the placebo group (see chart). How much is an effective dose
The amounts used in the various studies that proved effective ranged from 200 mg per day to as much as 1,050 mg per day. Somewhere in the middle, taking 200-400 mg 1-2 times daily, is probably the most effective dose as the incremental weight loss benefit of a higher dose above 800 mg a day was not that significant. The green coffee extract should be standardized to at least 45% chlorogenic acids. In summary
Green coffee extract has been shown to have many desirable health benefits. The primary
60-day study showed a weight loss differential of about 5.6 pounds between the control and green coffee extract users. That equates to 0.65 pounds of weight loss a week above and beyond regular dieting.
Since green coffee extract appears to work through a glucose mechanism, the benefits may be greater for those who have insulin resistance or those who eat too many carbohydrates.
It appears the media “buzz” on green coffee extract is in fact supported by the emerging science on this weight loss supplement. References:
Mubarak A, Bondonno CP, Liu AH, Considine MJ, Rich L, Mas E, Croft KD, Hodgson JM. Acute effects of chlorogenic acid on nitric oxide status, endothelial function, and blood pressure in healthy volunteers: a randomized trial. J Agric Food Chem. 2012 Sep 12;60(36):9130-6.
Shimoda, H., Seki, E. & Aitani, M. Inhibitory effect of green coffee bean extract on fat accumulation and body weight gain in mice. BMC Complement Altern Med. (2006); 6:9.
Vinson JA, Burnham BR, Nagendran MV. 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. 2012;5:21-7. doi: 10.2147/DMSO.S27665. Epub 2012 Jan 18.
Onakpoya I, Terry R, Ernst E. The use of green coffee extract as a weight loss supplement: a systematic review and meta-analysis of randomised clinical trials. Gastroenterol Res Pract. 2011.
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, Journal of International Medical Research, vol. 35, no. 6, pp.
O. Dellalibera, B. Lemaire, and S. Lafay, “Svetol_, green coffee extract, induces weight loss and increases the lean to fat mass ratio in volunteers with overweight problem,” Phytotherapie, vol. 4, no. 4, pp. 194–197, 2006.
Farah A, Monteiro M, Donangelo CM, Lafay S. Chlorogenic Acids from Green Coffee Extract are Highly Bioavailable in Humans. J Nutr. 2008 Dec;138(12):2309-2315.