Green Coffee Extract

July 29, 2011 Written by JP    [Font too small?]

Last week, I stopped into a popular coffee shop and ordered a large, iced Americano. While waiting to pay, I noticed an advertisement for a new line of icy, fruit flavored drinks that featured green coffee extract. That’s right, green coffee. Combining coffee and fruit may seem like an odd pairing, but, in reality, the flavor of raw coffee beans bears little to no resemblance to the brewed forms of coffee enjoyed the world over. Taste issues aside, you may be wondering why green coffee extract would be included in summery drinks and/or so called “functional foods” in the first place.

High heat processing, as is employed in coffee roasting, changes the antioxidant profile of coffee beans. One of the claims most often made about green coffee extract or GCE is that it is higher in antioxidants than conventional black coffee. This assertion is not without some basis in science. A study in the July 2001 issue of the Journal of Agricultural Food Chemistry reports that different varieties of green coffee beans (Arabica and Robusta) possess higher antioxidant activity prior to roasting. What’s more, human trials have determined that select antioxidants in GCE (chlorogenic acids) are absorbed well and result in reductions in plasma oxidative stress. (1,2,3)

As far as I’m concerned, green coffee’s greatest potential lies in the realm of cardiovascular health promotion. Several preliminary trials reveal that GCEs that are standardized for high levels of chlorogenic acids (CGAs) are capable of lowering diastolic and systolic blood pressure in a safe manner. A dosage of approximately 140 mg of CGAs/day appears to be a sufficient quantity of the active ingredient. A Japanese study from October 2004 attempted to uncover the mechanism by which green coffee exerts its antihypertensive effects. The findings presented in the journal Hypertension Research revealed a positive change in blood flow via improved vasoreactivity (reactive hyperemia ratio) and a significant decline in plasma homocysteine concentrations. Homocysteine is an amino acid which may contribute to cardiovascular disease when present in excess amounts. (4,5,6,7,8)

Green Coffee Beans Contain an Array of Potent Antioxidants

Source: BMC Complementary and Alternative Medicine 2006, 6:9 (link)

The most marketable reason to include green coffee in a food or product is the commonly made pronouncement that it can stimulate weight loss. A recent meta-analysis and systematic review in the journal Gastroenterology Research and Practice scientifically evaluated this enticing claim. A paltry three studies met the basic criteria required for inclusion in the summary. On average, the trials were relatively small and included between 30 – 62 participants. The daily dosage of green coffee extract used ranged from 180mg – 200mg/day. The studies took place over 4 weeks, 12 weeks and, again, 12 weeks. The weight loss reported was -2.97 lbs, -11.90 lbs and -10.96 lbs respectively. All of the trials were randomized and did not require additional dietary or lifestyle modifications that may have contributed to the noted reduction in weight. Ultimately, the authors of the review concluded that “the results from these trials are promising, but the studies are all of poor methodological quality. More rigorous trials are needed to assess the usefulness of GCE as a weight loss tool.” (9)

It’s vitally important to apply scientific research in a real world setting. It is plausible that green coffee extracts can, in fact, support a healthier weight in humans. Apart from the previously mentioned studies, animal and in vitro experiments have identified a number of ways by which GCE could reasonably accomplish this feat. Chief among the theories is green coffee’s ability to reduce glucose absorption in the intestines and prevent fat accumulation in the liver. However, it’s important to note that even in the best possible scenario, GCE is unlikely to do much for your waistline if you simply consume it in an occasional fruit drink. A daily, therapeutic quantity is the only thing that “may” assist with the goal of weight loss. Therefore, the most one can realistically expect from trendy drinks containing GCE is a temporary antioxidant boost and some momentary refreshment. But sometimes, that’s good enough. (10,11,12)

Note: Please check out the “Comments & Updates” section of this blog – at the bottom of the page. You can find the latest research about this topic there!

Be well!


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Posted in Diet and Weight Loss, Food and Drink, Nutritional Supplements

9 Comments & Updates to “Green Coffee Extract”

  1. Stephanie Says:

    I was diagnosed with fatty liver. Does Green Coffee Extract burn fat in your liver?

  2. JP Says:

    Hi Stephanie,

    Green coffee extract may help to reduce fat accumulation in the liver. However, the evidence for this is taken from a preliminary, animal study. Whether or not this effect is translatable to humans has yet to be determined.

    There are probably better ways of addressing fatty liver. Chief among them is to avoid dietary sources of concentrated fructose, exercise regularly and lose excess weight. A lower carbohydrate diet that is rich in fiber, healthy fats and whole foods is often a good choice. Additional tips that you might want to consider can be found below:

    Be well!


  3. JP Says:

    Update 05/27/15:

    Nutrition. 2015 Feb;31(2):292-7.

    Effect of post-exercise caffeine and green coffee bean extract consumption on blood glucose and insulin concentrations.

    OBJECTIVE: The aim of this study was to investigate the effects of ingesting caffeine and green coffee bean extract on blood glucose and insulin concentrations during a post-exercise oral glucose tolerance test.

    METHODS: Ten male cyclists (age: 26 ± 5 y; height: 179.9 ± 5.4 cm; weight: 77.6 ± 13.3 kg; body mass index: 24 ± 4.3 kg/m(2); VO2 peak: 55.9 ± 8.4 mL·kg·min(-1)) participated in this study. In a randomized order, each participant completed three 30-min bouts of cycling at 60% of peak power output. Immediately after exercise, each participant consumed 75 g of dextrose with either 5 mg/kg body weight of caffeine, 10 mg/kg of green coffee bean extract (5 mg/kg chlorogenic acid), or placebo. Venous blood samples were collected immediately before and after exercise during completion of the oral glucose tolerance test.

    RESULTS: No significant time × treatment effects for blood glucose and insulin were found. Two-h glucose and insulin area under the curve values, respectively, for the caffeine (658 ± 74 mmol/L and 30,005 ± 13,304 pmol/L), green coffee bean extract (637 ± 100 mmol/L and 31,965 ± 23,586 pmol/L), and placebo (661 ± 77 mmol/L and 27,020 ± 12,339 pmol/L) trials were not significantly different (P > 0.05).

    CONCLUSION: Caffeine and green coffee bean extract did not significantly alter postexercise blood glucose and insulin concentrations when compared with a placebo. More human research is needed to determine the impact of these combined nutritional treatments and exercise on changes in blood glucose and insulin.

    Be well!


  4. JP Says:

    Update 05/27/15:

    Nutrients. 2014 Nov 5;6(11):4881-94.

    Antihypertensive potential of combined extracts of olive leaf, green coffee bean and beetroot: a randomized, double-blind, placebo-controlled crossover trial.

    Extracts of olive leaf, green coffee bean and beetroot may deliver cardiovascular benefits. This study sought to evaluate the effects of regularly consuming a combination of these extracts on blood pressure (BP), arterial compliance, blood lipids, blood glucose and insulin sensitivity. A double-blind randomised placebo-controlled crossover trial was conducted in adults with untreated high normal or borderline elevated BP. They were randomised to take an active supplement, comprising 500 mg olive leaf extract, 100 mg green coffee bean extract and 150 mg beet powder, or a matching placebo twice daily for six weeks, followed by the alternate supplement for a further six weeks. Assessments of 24-h ambulatory BP (ABP), clinic BP arterial compliance (pulse-wave analysis), blood lipids, blood glucose and insulin were obtained at baseline and at the end of each treatment phase. Baseline clinic BP in 37 overweight middle-aged men and women who completed the trial averaged 145/84 mmHg. There was no significant effect of treatment on ABP or any other outcome measure. The failure to confirm prior evidence of the antihypertensive benefits of these extracts emphasises the importance of placebo control and the value of ABP monitoring. Further dose-response evaluation of olive leaf, green coffee bean or beetroot extracts is required to confirm or refute the purported benefits.

    Be well!


  5. JP Says:

    Update 05/27/15:

    Phytother Res. 2014 Jun;28(6):946-8.

    Lipolytic activity of Svetol®, a decaffeinated green coffee bean extract.

    The beneficial health effects of chlorogenic acids (CGAs), major components of coffee beans, are well known and have been attributed to multiple mechanisms of action. However, the lipolytic activity of CGAs does not appear to have been reported. We studied the effects of varying concentrations of Svetol®, a decaffeinated green coffee bean extract enriched in CGAs, on the liberation of free fatty acids from human adipocytes following short-term (2 h) and long-term (192 h) exposure. The results showed that although lipolytic activity observed following short-term incubation could be tentatively linked to residual caffeine traces in the sample, longer-term exposure clearly showed the effects of Svetol® on release of free fatty acids, and this effect was not due to caffeine. The results of this study provide a further mechanism by which to explain the long-term health benefits of CGAs and Svetol®.

    Be well!


  6. JP Says:

    Updated 04/20/17:

    Br J Nutr. 2017 Apr 17:1-6.

    Effects of subacute ingestion of chlorogenic acids on sleep architecture and energy metabolism through activity of the autonomic nervous system: a randomised, placebo-controlled, double-blinded cross-over trial.

    Chlorogenic acids (CGA) are the most abundant polyphenols in coffee. Continuous consumption of CGA reduces body fat and body weight. Since energy metabolism and sleep are controlled by common regulatory factors, consumption of CGA might modulate sleep. Lack of sleep has been identified as a risk factor for obesity, hypertension and type 2 diabetes. The aim of this study was to determine the effects of ingesting CGA over 5 d on energy metabolism and sleep quality in humans. A total of nine healthy subjects (four male and five female) completed a placebo-controlled, double-blinded, cross-over intervention study. Subjects consumed a test beverage containing 0 or 600 mg of CGA for 5 d. On the fifth night, subjects stayed in a whole-room metabolic chamber to measure energy metabolism; sleep was evaluated using polysomnographic recording. It was found that CGA shortened sleep latency (9 (sem 2) v. 16 (sem 4) min, P<0·05) compared with the control, whereas no effect on sleep architecture, such as slow-wave sleep, rapid eye movement or waking after sleep onset, was observed. Indirect calorimetry revealed that consumption of CGA increased fat oxidation (510 (sem 84) kJ/8 h (122 (sem 20) kcal/8 h) v. 331 (sem 79) kJ/8 h (81 (sem 19) kcal/8 h), P<0·05) but did not affect energy expenditure during sleep. Consumption of CGA enhanced parasympathetic activity assessed from heart-rate variability during sleep (999 (sem 77) v. 919 (sem 54), P<0·05). A period of 5-d CGA consumption significantly increased fat oxidation during sleep, suggesting that beverages containing CGA may be beneficial to reduce body fat and prevent obesity. Consumption of CGA shortened sleep latency and did not adversely affect sleep quality.

    Be well!


  7. JP Says:

    Updated 12/21/17:

    J Med Food. 2017 Dec 20.

    Effect of Chlorogenic Acid Administration on Glycemic Control, Insulin Secretion, and Insulin Sensitivity in Patients with Impaired Glucose Tolerance.

    Chlorogenic acid has been described as a novel polyphenol with metabolic effects on glucose homeostasis. The aim of this study was to evaluate the effect of chlorogenic acid administration on glycemic control, insulin secretion, and insulin sensitivity in patients with impaired glucose tolerance (IGT). A randomized, double-blind, placebo-controlled clinical trial was performed in 30 patients with IGT; 15 patients randomly assigned to oral chlorogenic acid received 400 mg three times per day for 12 weeks, and the other 15 patients received placebo in the same way. Before and after the intervention, anthropometric and metabolic measurements, including fasting plasma glucose (FPG), glycated hemoglobin A1c, and a lipid profile, were performed. Area under the curve of glucose and insulin as well as the insulinogenic, Stumvoll, and Matsuda indices were calculated. Wilcoxon, Mann-Whitney U, and chi-square tests were performed, and P ≤ .05 was considered statistically significant. There were significant decreases in FPG (5.7 ± 0.4 vs. 5.5 ± 0.4 mmol/L, P = .002), insulinogenic index (0.71 ± 0.25 vs. 0.63 ± 0.25, P = .028), body weight, body mass index, waist circumference, triglycerides, total cholesterol, low-density lipoprotein cholesterol, and very low-density lipoprotein levels in the chlorogenic acid group, with an increment in the Matsuda index (1.98 ± 0.88 vs. 2.30 ± 1.23, P = .002). There were no significant differences in the placebo group. In conclusion, chlorogenic acid administration in patients with IGT decreased FPG and insulin secretion, while increasing insulin sensitivity and improving both anthropometric evaluations and the lipid profile.

    Be well!


  8. JP Says:

    Updated 1/9/18:

    Br J Nutr. 2018 Jan 8:1-9.

    Effects of green coffee extract supplementation on anthropometric indices, glycaemic control, blood pressure, lipid profile, insulin resistance and appetite in patients with the metabolic syndrome: a randomised clinical trial.

    This study was conducted to elucidate the effects of decaffeinated green coffee bean extract (GCE) on anthropometric indices, glycaemic control, blood pressure, lipid profile, insulin resistance and appetite in patients with the metabolic syndrome (Mets). Subjects were randomly allocated to consume 400 mg GCE or placebo capsules twice per d for 8 weeks. Both groups were advised to follow an energy balanced diet. After GCE supplementation, systolic blood pressure (SBP) significantly reduced compared with the placebo group (-13·76 (sd 8·48) v. -6·56 (sd 9·58) mmHg, P=0·01). Also, GCE treatment significantly reduced fasting blood glucose (FBS) (-5·15 (sd 60·22) v. 29·42 (sd 40·01) mg/dl (-0·28 (SD 3·34) v. 1·63 (SD 2·22) mmol/l); P=0·03) and homoeostatic model of assessment of insulin resistance in comparison to placebo (-1·41 (sd 3·33) v. 1·23 (sd 3·84), P=0·02). In addition, waist circumference (-2·40 (sd 2·54) v. -0·66 (sd 1·17) cm, P=0·009) and appetite score (-1·44 (sd 1·72) v. -0·2 (sd 1·32), P=0·01) of the individuals supplemented with GCE indicated a significant decline. Besides, weight and BMI reduction in the intervention group was almost twice as much as the placebo group; however, this discrepancy was marginally significant (weight: -2·08 (sd 2·11) v. -0·92 (sd 1·30) kg, P=0·05). No difference was observed in terms of glycated Hb (HbA1c) percentage and lipid profile parameters between the two groups. To sum up, GCE administration had an ameliorating effect on some of the Mets components such as high SBP, high FBS and Mets main aetiological factors including insulin resistance and abdominal obesity. Furthermore, GCE supplementation could reduce appetite level.

    Be well!


  9. JP Says:

    Updated 03/29/19:

    Int J Food Sci Nutr. 2019 Mar 25:1-7.

    Chlorogenic acid-enriched green coffee bean extract affects arterial stiffness assessed by the cardio-ankle vascular index in healthy men: a pilot study.

    The effect of chlorogenic acid-enriched green coffee bean extract (cGCE) intake on arterial stiffness was investigated using the cardio-ankle vascular index (CAVI) as a novel surrogate marker for predicting arteriosclerosis. A placebo-controlled double-blind pilot study was conducted with 16 healthy Japanese men. Subjects were divided into two groups and consumed beverages containing either cGCE or placebo daily for 2 weeks. The CAVI, the primary endpoint of the study, was evaluated at the beginning of the study and 2 weeks later. Endothelium-dependent flow-mediated dilation (FMD) and sympathetic nervous activity (SNA), which are thought to be related to the CAVI, were also measured. The CAVI change was significantly greater in the cGCE group than in the placebo group. In addition, FMD increased and SNA decreased in the cGCE group. These findings suggest that 2-week ingestion of cGCE may improve arterial stiffness as assessed by the CAVI.

    Be well!


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