While some complementary and alternative techniques have been studied scientifically, high-quality data regarding safety, effectiveness, and mechanism of action are limited or controversial for most therapies. Whenever possible, it is recommended that practitioners be licensed by a recognized professional organization that adheres to clearly published standards. In addition, before starting a new technique or engaging a practitioner, it is recommended that patients speak with their primary healthcare provider(s). Potential benefits, risks (including financial costs), and alternatives should be carefully considered. The below monograph is designed to provide historical background and an overview of clinically-oriented research, and neither advocates for or against the use of a particular therapy.
“Green coffee” refers to the raw, unroasted seeds (beans) of Coffea fruits. Green coffee beans are cleaned, dried, roasted, ground, and brewed to produce the popular beverage coffee. The main Coffea species used for beverage production are Coffea arabica and Coffea canephora (synonym, Coffea robusta).
Coffee is a popular source of caffeine. However, it also contains many other components that are believed to have health benefits, such as lowering blood sugar levels. These components include chlorogenic acid, quinides, lignans, and trigonelline.
Studies suggest that caffeinated coffee consumption may increase blood pressure and potentially increase the risk of heart disease. However, these results were not found to be true of decaffeinated coffee, and some trials found that chlorogenic acid may actually lower blood pressure. Researchers believe that the differing effects of roasted and raw coffee are due to a compound called hydroxyhydroquinone (HHQ), which is created from the roasting process and may block the beneficial effects of chlorogenic acid on blood pressure.
Scientists believe that genes and gender may play a role in determining how people respond to chlorogenic acid. One study found that coffee consumption led to better insulin sensitivity in women, but not in men. However, further research is needed in order to better understand these findings.
These uses have been tested in humans or animals. Safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider.
|High blood pressure (hypertension)
Some studies found that chlorogenic acid in green coffee extract may lower blood pressure. More studies are needed before further conclusions can be made.
|Heart disease (risk)
Coffee consumption has been linked to increased blood pressure and higher levels of homocysteine, which are risk factors for heart disease. Further studies are needed to better understand this link.
|Impaired glucose tolerance
Studies suggest that coffee may improve blood sugar levels and reduce the risk of type 2 diabetes. More evidence is needed to understand the benefits of each component in green coffee, as well as long-term effects.
Green coffee extract may improve weight in obese people. However, there is conflicting evidence, and more research is needed to confirm this benefit.
*Key to grades:
The below uses are based on tradition or scientific theories. They often have not been thoroughly tested in humans, and safety and effectiveness have not always been proven. Some of these conditions are potentially serious and should be evaluated by a qualified health care professional.
- Aging, antiviral, cancer, cardiovascular health (heart health), cirrhosis (impaired liver function), colorectal cancer, diabetes, hepatitis B, hepatocellular carcinoma (liver cancer), infections, inflammation, liver disease, metabolic abnormalities (metabolic syndrome), Parkinson’s disease, pellagra (niacin deficiency).
The below doses are based on scientific research, publications, traditional use, or expert opinion. Many herbs and supplements have not been thoroughly tested, and safety and effectiveness may not be proven. Brands may be made differently, with variable ingredients, even within the same brand. The below doses may not apply to all products. You should read product labels, and discuss doses with a qualified healthcare provider before starting therapy.
Adults (18 years and older)
To reduce the risk of heart disease, a green coffee extract beverage containing 140 milligrams of chlorogenic acid has been taken by mouth daily for four months.
To improve blood sugar levels, 0.9 grams of Svetol® green coffee extract, 10 grams of CoffeeSlender® coffee, and 25 grams of sugar have been added to water and taken by mouth. One Svetol® tablet containing 200 milligrams of green coffee extract has been taken by mouth three times daily for 40 days.
To treat high blood pressure, 46 milligrams, 93 milligrams, and 185 milligrams of green coffee have been taken by mouth once daily for 28 days. A dose of 70-280 milligrams of chlorogenic acid has been taken by mouth daily for 12 weeks.
To manage obesity, 200 milligrams of Svetol® green coffee extract in 2,200 milligram sachets of caffeinated CoffeeSlender® coffee has been taken by mouth five times daily for 12 weeks.
Children (under 18 years old)
There is no proven safe or effective dose for green coffee extract in children.
The U.S. Food and Drug Administration does not strictly regulate herbs and supplements. There is no guarantee of strength, purity or safety of products, and effects may vary. You should always read product labels. If you have a medical condition, or are taking other drugs, herbs, or supplements, you should speak with a qualified healthcare provider before starting a new therapy. Consult a healthcare provider immediately if you experience side effects.
Avoid using in people who are allergic or sensitive to coffee, coffee parts (including molds and fungal toxin), and castor beans.
Side Effects and Warnings
Green coffee extract is considered safe in healthy people when taken by mouth in recommended doses for up to four months.
Green coffee extract may lower blood sugar levels. Caution is advised in people with diabetes or hypoglycemia, and in those taking drugs, herbs, or supplements that affect blood sugar. Blood glucose levels may need to be monitored by a qualified healthcare professional, including a pharmacist. Medication adjustments may be necessary.
Green coffee extract may cause low blood pressure. Caution is advised in people taking drugs or herbs and supplements that lower blood pressure.
Use cautiously in people who are overweight or obese, and in people who have heart disease or high blood pressure.
Avoid in people who are taking beta-blockers.
Avoid using in pregnant women, due to an increased risk of miscarriage, premature delivery, and low birthweight. Avoid using in breastfeeding women, due to a lack of safety information.
Green coffee extract may cause asthma, conjunctivitis (eye problems), coughing, decreased cholesterol, difficulty breathing, headache, increased allergic responses, increased blood pressure, increased heart rate, increased levels of homocysteine in the blood, increased risk of heart disease, increased risk of urinary tract infection, increased use of blood pressure-lowering drugs, kidney problems, narrowing of the bronchus, nausea, rhinitis (runny or stuffy nose), weight gain, and wheezing.
Note: Caffeine-related side effects may vary depending on the type of green coffee extract.
Pregnancy and Breastfeeding
There is currently a lack of scientific evidence on the use of green coffee extract during pregnancy or breastfeeding.
Most herbs and supplements have not been thoroughly tested for interactions with other herbs, supplements, drugs, or foods. The interactions listed below are based on reports in scientific publications, laboratory experiments, or traditional use. You should always read product labels. If you have a medical condition, or are taking other drugs, herbs, or supplements, you should speak with a qualified healthcare provider before starting a new therapy.
Interactions with Drugs
Green coffee extract may lower blood sugar levels. Caution is advised when using medications that may also lower blood sugar. People taking insulin or drugs for diabetes by mouth should be monitored closely by a qualified healthcare professional, including a pharmacist. Medication adjustments may be necessary.
Green coffee extract may cause low blood pressure. Caution is advised in people taking drugs that lower blood pressure.
Green coffee extract may also interact with agents that may reduce anxiety, antibiotics, anticancer agents, anticholinergics (agents that may block nerve impulses), antifungals, anti-inflammatories, antiobesity agents, antivirals, beta-blockers, calcium salts, cholesterol-lowering agents, cholinergic agonists (agents that may enhance nerve impulses), and iron salts.
Interactions with Herbs and Dietary Supplements
Green coffee extract may lower blood sugar levels. Caution is advised when using herbs or supplements that may also lower blood sugar. Blood glucose levels may require monitoring, and doses may need adjustment.
Green coffee extract may cause low blood pressure. Caution is advised in people taking herbs or supplements that lower blood pressure.
Green coffee extract may also interact with antibacterials, anticancer herbs and supplements, anticholinergics (herbs and supplements that may block nerve impulses), antifungals, anti-inflammatories, antiobesity herbs and supplements, antivirals, beta-carotene, calcium, carcinogenic or oxidative herbs and supplements (agents that may cause cancer), cholesterol-lowering herbs and supplements, cholinergics (herbs and supplements that may enhance nerve impulses), clove oil, cyclodextrin, curcumin, garlic, herbs and supplements that may reduce anxiety, iron, milk protein, minerals, probiotics, and vitamin E.
This information is based on a systematic review of scientific literature edited and peer-reviewed by contributors to the Natural Standard Research Collaboration (www.naturalstandard.com).
Natural Standard developed the above evidence-based information based on a thorough systematic review of the available scientific articles. For comprehensive information about alternative and complementary therapies on the professional level, go to www.naturalstandard.com. Selected references are listed below.
- Agardh EE, Carlsson S, Ahlbom A, et al. Coffee consumption, type 2 diabetes and impaired glucose tolerance in Swedish men and women. J.Intern.Med. 2004;255(6):645-652. View Abstract
- Arion WJ, Canfield WK, Ramos FC, et al. Chlorogenic acid and hydroxynitrobenzaldehyde: new inhibitors of hepatic glucose 6-phosphatase. Arch.Biochem.Biophys. 3-15-1997;339(2):315-322. View Abstract
- Dupas C, Marsset, Baglieri A, et al. Chlorogenic acid is poorly absorbed, independently of the food matrix: A Caco-2 cells and rat chronic absorption study. Mol.Nutr.Food Res. 2006;50(11):1053-1060. View Abstract
- Greenberg JA, Boozer CN, and Geliebter A. Coffee, diabetes, and weight control. Am.J.Clin.Nutr. 2006;84(4):682-693. View Abstract
- Herling AW, Burger HJ, Schwab D, et al. Pharmacodynamic profile of a novel inhibitor of the hepatic glucose-6-phosphatase system. Am.J.Physiol 1998;274(6 Pt 1):G1087-G1093. View Abstract
- Higdon JV and Frei B. Coffee and health: a review of recent human research. Crit Rev.Food Sci.Nutr. 2006;46(2):101-123. View Abstract
- Hu G, Jousilahti P, Nissinen A, et al. Coffee consumption and the incidence of antihypertensive drug treatment in Finnish men and women. Am.J.Clin.Nutr. 2007;86(2):457-464. View Abstract
- Mori H, Kawabata K, Matsunaga K, et al. Chemopreventive effects of coffee bean and rice constituents on colorectal carcinogenesis. Biofactors 2000;12(1-4):101-105. View Abstract
- Namba T and Matsuse T. [A historical study of coffee in Japanese and Asian countries: focusing the medicinal uses in Asian traditional medicines]. Yakushigaku.Zasshi 2002;37(1):65-75. View Abstract
- Olthof MR, Hollman PC, Zock PL, at al. Consumption of high doses of chlorogenic acid, present in coffee, or of black tea increases plasma total homocysteine concentrations in humans. Am.J.Clin.Nutr. 2001;73(3):532-538. View Abstract
- Suzuki A, Fujii A, Jokura H, et al. Hydroxyhydroquinone interferes with the chlorogenic acid-induced restoration of endothelial function in spontaneously hypertensive rats. Am.J.Hypertens. 2008;21(1):23-27. View Abstract
- Suzuki A, Fujii A, Yamamoto N, et al. Improvement of hypertension and vascular dysfunction by hydroxyhydroquinone-free coffee in a genetic model of hypertension. FEBS Lett. 4-17-2006;580(9):2317-2322. View Abstract
- Suzuki A, Kagawa D, Ochiai R, et al. Green coffee bean extract and its metabolites have a hypotensive effect in spontaneously hypertensive rats. Hypertens.Res. 2002;25(1):99-107. View Abstract
- van Dam RM and Hu FB. Coffee consumption and risk of type 2 diabetes: a systematic review. JAMA 7-6-2005;294(1):97-104. View Abstract
- Yamaguchi T, Chikama A, Mori K, et al. Hydroxyhydroquinone-free coffee: a double-blind, randomized controlled dose-response study of blood pressure. Nutr.Metab Cardiovasc.Dis. 2008;18(6):408-414. View Abstract
Copyright © 2013 Natural Standard (www.naturalstandard.com)
The information in this monograph is intended for informational purposes only, and is meant to help users better understand health concerns. Information is based on review of scientific research data, historical practice patterns, and clinical experience. This information should not be interpreted as specific medical advice. Users should consult with a qualified healthcare provider for specific questions regarding therapies, diagnosis and/or health conditions, prior to making therapeutic decisions.