Green Coffee Extract: Unique Obesity Intervention
By Michael Downey •
January 8, 2013
Reduce Blood Glucose and Shed Pounds Fast
According to the World Health Organization, some 1.5 billion people are obese or overweight.(1) Each of these obese individuals runs up to a three times increased risk of death compared to normal-weight people.(2)
Obesity results in shortening of the life span by an average eight to ten years compared with people at normal weight. For every 33 extra pounds, risk of early death increases by around 30%.(3) Beyond just looking good, shedding extra pounds is a proven life-saving strategy.
The good news is that scientists have found green coffee bean extract can intervene in a unique way to inhibit the process behind obesity.
Now recognized as a complex metabolic disease itself and not merely a “risk factor,”(4) obesity occurs when excess calorie consumption overwhelms the body’s ability to expend calories as energy.(5-9) Then, the obesity disease process causes further increases in body fat and blood glucose levels.
In this article, you will learn how chlorogenic acid compounds in green coffee bean extract work in the intestinal tract to inhibit the absorption of calories.(10-11) Green coffee bean extract also works along multiple pathways to reduce [body] fat(12-16) and glucose levels.(15,17-27)
In a small but compelling placebo-controlled study reported January 2012, a formulation of green coffee bean extract produced weight loss in 100% of the overweight participants - who lost an average of over 17.6 pounds and reduced their body fat.(28) Without changing their consumption of calories, protein, or carbohydrates, or their exercise habits - a remarkable 37% of participants reversed their pre-obesity status (25-30 BMI) back into the normal-weight range.(28)
Obesity Now Defined as ‘Chronic Metabolic Disease’
Recent research placed the overall risks of obesity into clear and frightening perspective: scientists concluded that the healthcare costs associated with obesity exceed those associated with smoking.(29) With that level of risk, it’s important that we view obesity as the complex disease that scientists now know it to be.(4)
As a disease, the scientific community now specifically recognizes obesity to be a chronic metabolic disorder, one that plays a key role in the induction of many age-related diseases - and early death.(30) Obesity alters the body’s pulmonary, endocrine, and immunological functions.(4)
For example, a study concluded that adipose (fat) tissue is not simply a passive fat storehouse, but an active endocrine organ capable of synthesizing a variety of molecules and releasing them into the bloodstream, where they can disrupt the normal metabolic balance and cause a host of diseases.(30,31)
Scientists have learned that this metabolic disruption can trigger diabetes,(31) hypertension and cardiovascular disease,(30,31) non-alcoholic fatty liver disease (NAFLD),(32,33) liver and colorectal cancer,(33) and various digestive diseases.(32)
With these risk factors, it is easy to understand why obesity involves a 200%-300% higher risk of death than being of normal weight(3) -and why excess body fat may be robbing almost 2 out of 3 people of both quality and quantity of life.(1,4)
The medical establishment’s longstanding answer to the obesity epidemic has been “more exercise and a balanced diet.” And body weight often comes down in response to striking a balance between energy (food) intake and energy expenditure (physical activity).(7-9)
But the contribution of other factors is poorly understood, and obesity can, in part, be a response to environmental stimuli, genetic predisposition, and endocrinological (hormonal) abnormalities.(4)
Reversing an obesity epidemic of this magnitude requires attacking it on several fronts, including exercise, diet - and novel interventions. So scientists have been investigating the safest and most effective, natural agents that might hold the ability to actively halt obesity’s underlying process.
Following the Clues to a Unique Obesity Intervention
Extensive epidemiological evidence had previously shown that a high level of coffee consumption lowers the risk of type 2 diabetes by 67%.(34) This anti-diabetic effect appeared to result from reduced levels of blood glucose, increased insulin sensitivity, and decreased storage of both fat and carbohydrate.
To scientists, this suggested that compounds in the coffee bean can somehow modify digestion or metabolism. It also suggested, confirmed by a later review,(35) that the anti-diabetic benefit from coffee may stem from a weight-reducing effect - because excess weight is a well-known risk factor for diabetes.
Further research, including a meta-analysis that combined data on over 450,000 people, discovered that decaffeinated coffee provided the same protective effects as caffeinated.(36-40) This proved to scientists that coffee’s ability to affect digestion or metabolism stemmed from non-caffeine compounds in the coffee bean, most likely chlorogenic acid, possibly enhanced by other coffee bean compounds.
Studies then found that caffeine stimulates glucose absorption, whereas chlorogenic acid in coffee antagonizes glucose uptake.(21)
It apparently does so by shifting the glucose uptake to more distal regions of the small intestine.(21) It also seems to inhibit amylase, the enzyme that breaks down starch into sugar.(10)
Scientists recognized from these findings that coffee’s chlorogenic acids represented a potential breakthrough against obesity - because these compounds may be helping coffee drinkers to prevent diabetes by an inhibition of weight gain, effected by a reduction in glucose levels(2) and by - the Holy Grail of anti-obesity efforts - a decrease in intestinal calorie uptake.(10,28)
Confirmation of this began with a study concluding that the chlorogenic acids in coffee inhibit glucose-6-phosphatase, in turn interfering with glucose synthesis and release within the body.(19) This lowers blood sugar levels - and promotes weight loss.
This study also found that chlorogenic acid reduces the hyperglycemic peak associated with carbohydrate ingestion.(19) This lowers insulin activity and reduces adipose tissue accumulation(40) - both associated with weight loss. Additionally, research has confirmed that compounds in coffee decrease adipose tissue.(13)
With increasing support for the weight-loss effect of coffee compounds, scientists set out to investigate specifically the effects of coffee on weight.
In a human study, daily consumption of coffee that was rich in the compounds that are found abundantly in green coffee beans, and also in roasted beans, did indeed result in a lower energy (food) intake - which caused reduced weight and body fat.(41) Scientists wondered if even greater calorie-blocking and weight loss could be achieved by a higher concentration of chlorogenic acids in the coffee.(17,18)
Green Coffee Bean Extract Inhibits Calorie Absorption
To investigate the weight-reducing effect that had been shown in roasted and brewed coffee, scientists turned to compounds extracted directly from green coffee beans. The green coffee beans contain higher amounts of chlorogenic acid and other polyphenol compounds that are substantially lost during the roasting process that turns them brown.
Investigators tested two agents on mice: chlorogenic acid, a key green coffee bean compound and green coffee bean extract. They found that chlorogenic acid alone showed a moderate weight-reducing effect. However, the green coffee bean extract produced greater weight loss.(13) This was attributed to its ability to inhibit the absorption of fats from the intestine and enhance fat metabolism in the liver.(13)
Further testing involving induced-obese mice administered a high-fat diet (37% calories from fat) confirmed these findings.(16)
In other research with mice, coffee polyphenols enhanced energy metabolism, decreased lipogenesis (the formation of fat) and inhibited weight gain. The researchers found a suppression of body fat, which resulted from a downregulating of sterol regulatory element-binding protein and related molecules.(14)
Encouraged by the anti-obesity effect of these extracts in animals, scientists designed new experiments to confirm that green coffee bean extract would significantly decrease body weight in humans.
In a 12-week, placebo-controlled study, scientists tested the efficacy of green coffee bean extract.
Thirty overweight or obese human volunteers took either the extract or a placebo, dissolved in instant coffee. The extract produced an average 11 pound weight loss. This was paralleled by a decrease in glucose absorption and an increase in glucose utilization. The researchers reported that the lower availability of glucose that results from these effects would cause the body to increase the metabolism of fat reserves, which would eventually decrease body fat and mass.(17)
By this point, scientists had accumulated substantial evidence that both caffeinated and decaffeinated coffee - and especially, green coffee bean extract - significantly reduce the absorption of glucose,(17,19,21) and the absorption of fats.(13,16) There was also evidence of a decrease in the enzyme amylase,(10) which would reduce the absorption of carbohydrates. These effects indicated that green coffee bean extract decreases absorption of calories and produces substantial weight loss.(17)
A 2011 review and meta-analysis of published and unpublished human studies involving randomized clinical trials using green coffee bean extract in doses of 180 mg to 200 mg daily concluded that there was an overall decrease in body weight. However, the scientists concluded that further rigorous research was needed to conclusively establish the weight-loss efficacy of the extract.(42)
Compelling Weight-Loss Results
To determine conclusively that green coffee bean extract has a potent anti-obesity benefit, scientists set up a study of rigorous design: a randomized, double-blind, placebo-controlled, linear dose, crossover study on humans.
In a crossover study, participants are cycled through different phases of treatment and placebo. In this case, subjects took a high dose of green coffee bean extract for 6 weeks, a lower dose green coffee bean extract for 6 weeks, and a placebo for 6 weeks in a randomized, double-blind manner. Between phases, there was a 2-week “washout” period, making the entire study 22 weeks long.
Crossover studies are considered sound, because each person in the test group serves as his or her own control. This improves the chances of getting an accurate result, because it eliminates the possibility of the outcome reflecting a difference between the active and control groups. Instead, any difference in results can be attributed with much greater confidence to the different supplements taken.
To ensure the findings were more representative, the investigation enlisted both men and women. Participants were restricted to those who were classified by their BMI as obese or pre-obese, because those who have these conditions are subject to obesity’s metabolic effects and find weight loss difficult to achieve. To avoid any confounding effect from drugs, subjects were excluded if they had taken any medications known to influence weight during the previous 6 months.
To further ensure that any effect on weight, body fat or BMI could be solely attributed to the extract, there were no significant changes in dietary calories or in the dietary percentages of carbohydrates, fat, and proteins at any time during the study. There were also no significant changes in exercise. The daily capsules were the only intervention, although in a non-study situation, people seeking weight reduction would ideally combine this intervention with lower calorie consumption and greater physical activity to promote maximum weight loss.
During the high-dose phase, subjects took 350 mg of extract, three times daily. The lower dose phase included 350 mg of extract, taken twice daily. The placebo phase involved a 350 mg dose three times daily of an inert capsule containing an inactive substance.
In January 2012, the scientists reported the striking results.
Although there were no changes in calorie intake or exercise over the 22-week trial, the investigators found that all subjects experienced an impressive reduction in body weight, BMI, and body fat during both the high-dose and low-dose phases of the study, but not in the placebo phase. After just 12 weeks of administering green coffee bean extract over the course of the 22-week study, the scientists found that:(28)
Weight decreased by over 17.6 pounds on average - with some subjects losing more than 22.7 pounds.
BMI decreased by an average of 2.92.
Body fat decreased by an average 4.44%, with some subjects losing 6.44% of their body fat.
Heart rate decreased by a significant average of 2.56 beats per minute.
The substantial anti-obesity impact was clearly reflected in the finding that a remarkable 37% of participants who were assessed as having pre-obesity (25-30 BMI) at the start of the study had their condition reversed to the normal-weight range!(28)
A study follow-up showed that, contrasting with food-restriction diets, a surprising 87.5% of the test subjects were able to maintain their weight loss after completing the study.(28) No side effects were observed.
Exploring the Biochemical Mechanisms
Research into exactly how green coffee bean extract produces its dramatic pound-shedding effect is in its early stages. However, existing evidence indicates that this powerful coffee extract has the ability to safely decrease the intestinal uptake of glucose, fats, and carbohydrates - and reduce the absorption of calories. Research shows that it also interferes with glucose transport and the production and storage of fats; and promotes utilization of glucose and breakdown of fats. Scientists speculate that its multiple biochemical mechanisms may work to:
• Inhibit the enzyme amylase, which would decrease the gastrointestinal tract absorption of sugar and calories(10)
• Interfere with glucose-6-phosphatase, an enzyme involved in creation of often surplus blood glucose from protein and fats(19)
• Suppress accumulation of hepatic triglycerides(13)
• Alter body-fat distribution(16)
• Downregulate fatty acid and cholesterol biosynthesis(16)
• Upregulate fatty acid oxidation and expression of peroxisome proliferator-activated receptor alpha (PPAR-alpha), a key regulator of lipids and glucose(15,16)
• Interfere with glucose transport(21)
• Inhibit pancreatic lipase, an enzyme that breaks down fats in the digestive tract(11)
• Retard absorption of fats from the intestine, and activate fat metabolism in the liver(13)
• Enhance energy metabolism(14)
• Reduce lipogenesis and fat accumulation by downregulating sterol regulatory element-binding protein and similar molecules(14)
• Inhibit the enzyme alpha-glucosidase, which breaks apart complex sugars and enhances their absorption into the blood(43)
• Increase the signal protein for insulin receptors in liver cells, increasing insulin sensitivity and decreasing glucose levels(22)
• Antagonize glucose uptake in the proximal small intestine, shifting absorption to more distal regions of the small intestine, thus reducing overall glucose uptake(21)
• Promote synthesis of the homeodomain transcription factor IDX-1, which helps the insulin-regulating beta cells respond to increases in plasma glucose(24)
• Promote dispersal of the sodium ion (Na+) electrochemical gradient, in turn reducing glucose absorption(27)
• Enhance whole-body metabolism, as shown by greater oxygen consumption.(14)
Whatever the mechanism through which green coffee bean extract delivers its beneficial effects, it has been shown to have a unique anti-obesity benefit: It substantially reduces body weight and body fat - even without a change in exercise or calorie consumption!(28)
Obesity increases the risk of chronic diseases and puts its victims at a 200%-300% greater risk of death.(3,4)
The good news is that scientists have found that green coffee bean extract can intervene in a unique way to inhibit the process behind obesity. Its compounds can reduce levels of fat(11-16) and glucose(14,15,17-27) in the body - and can decrease the absorption of calories.(10)
In a recent, placebo-controlled study on humans, green coffee bean extract decreased weight by a remarkable average of over 17.6 pounds.(28) And 37% of participants reversed their pre-obesity status back to the normal-weight range.(28) These results confirm that green coffee bean extract is a unique and potent intervention to halt obesity.
1. Available at: http://www.who.int/mediacentre/factsheets/fs311/en/. Accessed on April 24, 2012.
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37. Greenberg JA, Axen KV, Schnoll R, Boozer CN. Coffee, tea and diabetes: the role of weight loss and caffeine. Int J Obes Relat Metab Disord. 2005;29:1121-9.
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39. Wu T, Willett WC, Hankinson SE, Giovannucci E. Caffeinated coffee, decaffeinated coffee, and caffeine in relation to plasma C-peptide levels, a marker of insulin secretion, in U.S. women. Diabetes Care. 2005;28:1390-6.
40. Loopstra-Masters RC, Liese AD, Haffner SM, Wagenknecht LE, Hanley AJ. Associations between the intake of caffeinated and decaffeinated coffee and measures of insulin sensitivity and beta cell function. Diabetologia. 2011 Feb;54(2):320-8.
41. Bakuradze T, Boehm N, Janzowski C, et al. Antioxidant-rich coffee reduces DNA damage, elevates glutathione status and contributes to weight control: results from an intervention study. Mol Nutr Food Res. 2011 May;55(5):793-7.
42. Onakpova I, Terry R, Ernst E. The use of green coffee extract as a weight loss supplement: a systematic review and meta-analysis of randomized clinical trials. Gastroenterol Res Pract. 2011;2011.
43. Ishikawa A, Yamashita H, Hiemori M, et al. Characterization of inhibitors of postprandial hyperglycemia from the leaves of Nerium indicum. J Nutr Sci Vitaminol. 2007 Apr;53(2):166-73.
* This article is excerpted with kind permission from the July 2012 issue of Life Extension Magazine (www.LEF.org/magazine).©1995-2012 Life Extension® All rights reserved.
Note: These statements have not been evaluated by the FDA, and are not intended to prevent, diagnose, treat or cure any illness, condition or disease. Never make a change in your healthcare plan or diet, exercise, or supplementation regimens without first researching and discussing it in collaboration with your professional healthcare team.
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