Quick Navigation

Green Coffee Extract

Green Coffee Extract is a concentrated source of dietary Chlorogenic Acid and is currently being used for heart health and fat loss as a supplement; it seems weakly to moderately effective on these parameters.

Our evidence-based analysis on green coffee extract features 18 unique references to scientific papers.

Research analysis led by and reviewed by the Examine team.
Last Updated:

Easily stay on top of the latest nutrition research

Become an Examine Member to get access to all of the latest nutrition research:

  • Unlock information on 400+ supplements and 600+ health topics.
  • Get a monthly report summarizing studies in the health categories that matter specifically to you.
  • Access detailed breakdowns of the most important scientific studies.

Try FREE for 14 days

Research Breakdown on Green Coffee Extract


1Sources and Summary

1.1Composition

  • Chlorogenic Acid compounds, which are small phenolics bound to Quinic Acid; commonly seen as the main active component of Green Coffee Extract[4] with about 7-12g per 100g before processing and up to 42.2% of all phenolics.[5] The major chlorogenic acids appear to be dicaffeoylquinic (3,4-, 3,5-, and 4,5) and all caffeoyl, feruloyl, and p-coumaroyl quinic acids at 3-, 4-, and 5- positions,[4] although caffeoylquinic acids are the major ones. There does not appear to be much difference in the quantities of isomers relative to each other[4]

  • Epicatechin (21.6% of phenolic content) and Catechin (2.2%)[5]

  • Isochlorogenic acids I (5.7%), II (19.3%), and III (4.4%); all in reference to total phenolic content[5]

  • Caffeine

  • Ferulic Acid at 1% Phenolics[5] (although Chlorogenic acids may metabolize into Ferulic acid after ingestion)[6]

  • Caffeoyltryptophan (26.25umol/g)[4]

  • Rutin at 2.2% of total phenolics (form of Quercetin)[6]

  • Terpene esters Kahweol palmitate and Cafestol palmitate (as well as both Kahweol and Cafestol)[7]

Roasting green coffee beans may induce the Chlorogenic acids to form lactone structures,[8] and chlorogenic acid is detectable in plasma regardless of roasting[9] or raw extracts.[4]

2Pharmacology

2.1Absorption

After ingestion of 400mg decaffeinated Green Coffee Bean extract (170mg Chlorogenic acids), absorption rates of Chlorogenic acids and phenolics appear to exceed 30% suggesting high absorption rates.[4]

2.2Serum

After oral ingestion of 5-caffeoylquinic acid in isolation to rats, there is a detectable level of plasma Caffeic Acid and Ferulic Acid while the blood levels of 5-caffeoylquinic acid itself were below detectable levels even after 200mg/kg; suggestive of rapid metabolism.[6] Caffeic Acid and Ferulic acid peak at 6 and 9 hours post ingestion of 200mg/kg 5-Caffeoylquinic acid reaching 179ng/mL and 174ng/mL respectively, with a detectable level observed up until 24 hours.[6] Caffeoylquinic acids in general consist of 44% of serum phenolic metabolites in humans (31.3, 7.5, and 5.2% for 3-, 4-, and 5- respectively) and 55% of the Chlorogenic Acids, with dicaffeoylquinic acids and ferulic acid comprising most of the rest.[4]

The one human study assessing 400mg Green Coffee Bean extract (170mg Chlorogenic Acids; CGAs) noted high interindividual variability, although the Tmax of most phenolics was in the range of 3-4 hours (2.5 for p-coumaric acid) and, after 170mg Chlorogenic acids, the Cmax of total CGAs was 14.8+/-11.7umol/L).[4]

3Cardiovascular Health

3.1Blood Pressure

In rats, 180-720mg/kg Green Coffee Extract (28% Chlorogenic Acid) is able to acutely reduce blood pressure in spontaneously hypertensive rats over 12 hours in a dose-dependent manner (6.8-12.5%), with the two higher doses still being significant at 24 hours (5.7-11.1%);[6] a reduction of heart rate was also noted, only occurred at the highest dose in control group (Wistar Kyoto rats), and was thought to be due to the 5-caffeoylquinic acid content, which degrades into Ferulic Acid (active compount).[6] A component of Green Coffee Extract, ferulic acid, was then shown to enhance the activity of tested blood pressure lowering medications acutely (Nicardipine, Captopril, and Prazosin).[6]

One study using Green Coffee Extract (480mg) with a 30.9% Chlorogenic Acid content (140mg) daily for 12 weeks in men with essential hypertension noted reductions in heart rate (8%), diastolic blood pressure (7%), and systolic blood pressure (8%); all benefits appears to occur at week 4 and were maintained for 12 weeks, and trended towards baseline after 2 weeks of cessation.[10] Another study (20 otherwise healthy men, but with impaired vasoreactivity and blood flow) has also noted improvements to blood health in response to Green Coffee extract (140mg Chlorogenic acids via liquid test drink) for 4 months was able to increase the reactive hyperemia ratio in response to strain gauge plethysmogram () by 69% when placebo experienced a nonsignificant decrease; a trend to decrease blood pressure was noted (from 115/69 to 110/63) but this was not statistically significant.[11]

Low doses have been noted to reduce blood pressure in one study of prehypertensive persons; may be temporary, and possibly works via the Chlorogenic Acid content breaking down into Ferulic Acid. Has also been noted to increase vasoreactivity,

4Interactions with Glucose Metabolism

4.1Interventions

Acutely, 10g of Chlorogenic Acid (CGA) enriched Green Coffee (10g of coffee powder, at 4-4.5% CGA totalling 400-450mg CGA) is able to reduce the Area Under Curve (AUC) of glucose in response to 25g sucrose by 7% over 120 minutes post consumption.[12]

A study conducted in persons with prehypertension that also measured blood glucose (as part of a safety panel) noted that in persons with elevated but not prediabetic levels of blood glucose (89-109mg/dL) failed to note any significant reductions over 12 weeks using 480mg of Green Coffee Extract (30.9%, or 140mg, of Chlorogenic Acid).[10]

5Interactions with Fat Mass

5.1Interventions

In mice, 0.5-1% of the diet as Green Coffee bean extract is able to reduce body weight gain in mice while both isolated caffeine and chlorogenic acid showed a trend to do so.[13] The authors noted that Chlorogenic Acids could reduce triglyceride accumulation in the liver (caffeine ineffective) and caffeine could reduce circulating triglycerides after an olive oil test (feeding olive oil to mice acutely; chlorogenic acid ineffective) while the metabolite of chlorogenic acid, ferulic acid, increased fatty acid oxidation in the liver.[13]

A Meta-Analysis[1] conducted on the topic assessing noted that out of 5 human trials on Green Coffee Extract (GCE) that only three measured weight as a primary endpoint and that these trials had a large degree of heterogeneity and high risk of bias (with only one being indexed in Medline,[12] and two associated with for-profit companies of which only one can be located online[14] and one downloadable pdf[15]);[1] the average weight loss was 2.47kg according to this meta-analysis. The one trial indexed in Medline noted that weight loss over 12 weeks in obese persons (When 11g of Green Coffee giving 440-495mg Chlorogenic Acid daily) reached 5.4+/-0.6kg (with control coffee reaching 1.7+/-0.9kg; significantly less) and appeared to reduce fat mass by 3.6%, which comprised about 80% of total weight loss.[12] Only one other study prior to the conductance of this meta-analysis has assessed weight loss in persons with GCE, and this study that measured weight (not as the main study parameter) noted that 0.48g of GCE for 12 weeks (conferring 140mg Chlorogenic Acid) failed to reduce weight,[10] while studies conducted afterwards (and thus excluded) note that in overweight (n=16) adults given 700mg (2 doses of 350mg) Green Coffee Extract at 45.9% Chlorogenic Acid noted weight loss;[2] specifically, all subjects underwent periods of 350mg, 700mg, or placebo for 8 weeks each in randomization noted that weight loss over time was associated with the periods of Green Coffee Extract.[2]

Limited evidence to support the notion that Chlorogenic acids and their vessel, Green Coffee Extract, induce weight loss. That being said, despite numerous studies having potential conflicts of interest other independent studies also note weight loss may occur to a small degree in overweight subjects (lean subjects not yet tested)

6Interactions with Oxidation

6.1Glutathione

Glutatione, an antioxidant enzyme, is induced in activity by the diterpene ester Kahweol palmitate and its monoacetate Kahweol; Cafestol can induce activity as well, although the palmitate bound to it reduces activity.[7] 20% Green Coffee Extract to the diet of rats for 12 days appears to increase hepatic glutathione activity 5-fold relative to control (with intestinal mucosa having a smaller spike in activity), which was mostly replicated with 2.5mg of either diterpene in isolation.[7]

7Safety and Toxicity

7.1Allergy

Green coffee extracts, supplemental or food products, may cause a respiratory response indicative of allergens.[16] Occupational type I allergies have been noted to be associated with Green Coffee dust, which may be due to the presence of a 'Cof A 1' allergin.[17] This allergin is different than that of castor beans (both of which are known to induce occupational allergies in those who handle them)[18] and appears to be present in the plants Coffea canephora, Coffea Arabica, and Coffea liberica.[17]

It is possible to be allergic to Green Coffee Extracts, which appears to be related to an allergin that may also be present in common Coffee products

References

  1. ^ a b c 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)
  2. ^ a b c Vinson JA1, 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)
  3. ^ Randomized, double-blind, placebo-controlled, linear dose, crossover study to evaluate the efficacy and safety of a green coffee bean extract in overweight subjects {Retraction}.
  4. ^ a b c d e f g h Farah A, et al. Chlorogenic acids from green coffee extract are highly bioavailable in humans. J Nutr. (2008)
  5. ^ a b c d Phenolic compounds in coffee pulp: Quantitative determination by HPLC.
  6. ^ a b c d e f g Suzuki A, et al. Green coffee bean extract and its metabolites have a hypotensive effect in spontaneously hypertensive rats. Hypertens Res. (2002)
  7. ^ a b c Lam LK, Sparnins VL, Wattenberg LW. Isolation and identification of kahweol palmitate and cafestol palmitate as active constituents of green coffee beans that enhance glutathione S-transferase activity in the mouse. Cancer Res. (1982)
  8. ^ Farah A, et al. Effect of roasting on the formation of chlorogenic acid lactones in coffee. J Agric Food Chem. (2005)
  9. ^ Chlorogenic Acid Compounds from Coffee Are Differentially Absorbed and Metabolized in Humans.
  10. ^ a b c Watanabe T, et al. The blood pressure-lowering effect and safety of chlorogenic acid from green coffee bean extract in essential hypertension. Clin Exp Hypertens. (2006)
  11. ^ Ochiai R, et al. Green coffee bean extract improves human vasoreactivity. Hypertens Res. (2004)
  12. ^ a b c Thom E. 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 Int Med Res. (2007)
  13. ^ a b 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)
  14. ^ The Effect of Chlorogenic Acid Enriched Coffee (Coffee Shape) on Weight When Used in Overweight People.
  15. ^ Svetol®, green coffee extract, induces weight loss and increases the lean to fat mass ratio in volunteers with overweight problem.
  16. ^ Zuskin E, et al. Bronchial reactivity in green coffee exposure. Br J Ind Med. (1985)
  17. ^ a b Manavski N, et al. Cof a 1: identification, expression and immunoreactivity of the first coffee allergen. Int Arch Allergy Immunol. (2012)
  18. ^ Lehrer SB, Karr RM, Salvaggio JE. Analysis of green coffee bean and castor bean allergens using RAST inhibition. Clin Allergy. (1981)