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Evidence for Efficacy (Human Data)
Clinical Trials
A double-blind, placebo-controlled cross over study in 27 healthy volunteers found that caffeinated coffee may increase microvascular endothelial function, as measured by blood pressure, finger blood flow, and post-occlusive reactive hyperemia of finger blood flow. Noguchi 2015
A double-blind randomized controlled trial with 10 competitively trained cyclists on the real and perceived effects of caffeine on anaerobic performance showed a shorter time to peak power when subjects thought they consumed caffeine but instead drank placebo. Anderson 2020
A systematic review through October 2019 identified 27 randomized controlled trials which studied the effect of green coffee supplementation on cardio-metabolic risk factors. Data showed that green coffee significantly reduced fasting blood sugar, insulin, triglyceride, and increased HDL. Morvaridi 2020
Consumption of 200 mg of caffeine enhanced creative problem-solving abilities but had no effect on creative idea generation or working memory in a randomized placebo-controlled between-subject double-blind study (n=88). Zabelina 2020
Erratum for: The effect of green-coffee extract supplementation on obesity: A systematic review and dose-response meta-analysis of randomized controlled trials. Gorji Z, et al. Phytomedicine. 2019. PMID: 31398662 [No abstract] Gorji 2020
Consumption of green coffee extract (GCE) altered fasting blood sugar according to combined results from meta-analysis of 10 RCTs. Sub-group analysis revealed insulin levels to be reduced when GCE was supplemented in dosages of =400 mg/day. Chen 2020
Green coffee extract reduced BMI and increased serum HDL-cholesterol compared to control in an RCT of 48 patients with nonalcoholic fatty liver disease. Triglyceride levels, hepatic steatosis grade, liver enzymes, and adiponectin levels did not show significant differences between groups. Hosseinabadi 2020
Consuming three cups of coffee shortened the mean time to passage of first flatus and defecation and to toleration of solid food compared to no treatment in an RCT of 103 patients undergoing elective cesarean section. Bozkurt Koseoglu 2020
A randomized, crossover, acute feeding study compared the effects of drinking different types of coffee before a high-glycaemic index (GI) meal on postprandial glucose metabolism and assessed the effects of adding milk and sugar into coffee in 21 healthy adults. Wong 2020
Peak plasma glucose and insulin concentrations were unaffected by poor sleep quality (hourly sleep fragmentation) but were higher following coffee consumption after fragmented sleep in a randomized cross-over study of 29 adults. Smith 2020
In a randomized placebo-controlled pilot study, consumption of 200 mg caffeine plus 200 mg chlorogenic acid for 3 months was more effective than either coffee or chlorogenic acid plus placebo in reducing body weight in 26 patients with diabetes and non-alcoholic fatty liver disease. Mansour 2020
Comprehensive systematic review and dose-response meta-analysis summarized all available evidence from 15 randomized controlled trials, showing a significant reducing effect of green coffee extract supplementation on body weight but not on body fat percentage and waist to hip ratio. Asbaghi 2020
In a clinical study of 126 pregnant patients with isolated borderline oligohydramnios, drinking one cup of instant coffee increased amniotic fluid index compared to control (no coffee), but had no apparent effect on fetal renal artery blood flow. Madendag 2020
Meta-analysis of 14 clinical trials (n=766) found a significant reducing effect of green coffee extract supplementation on fasting blood glucose, serum insulin and total serum cholesterol. A reduction was seen in serum LDL and LDL in studies longer than 8 weeks that included female subjects. Asbaghi 2020
Comment on: The effect of green coffee extract supplementation on anthropometric measures: A comprehensive systematic review and dose-response meta-analysis of randomized controlled trials [No abstract] R Fuller 2020
Meta-analysis of 5 randomized controlled trials showed the use of green coffee bean extract supplements resulted in a significant change in C-reactive protein levels, with a greater reduction noted with doses = 1000 mg/d, interventions less than 4 weeks, and for non-healthy subjects. Chen 2020
Erratum for: Effects of Bang® Keto Coffee Energy Drink on Metabolism and Exercise Performance in Resistance-Trained Adults: A Randomized, Double-blind, Placebo-controlled, Crossover Study. [No abstract] Harty 2020
In a randomized, controlled study, median times to flatus and defecation and mean time to tolerate food were decreased in patients who consumed coffee vs. warm water (control) after laparoscopic gynecological surgery (n=96). Gungorduk 2020
An energy drink (Bang® Keto Coffee; 130 kcal, 300 mg caffeine, 20 g protein) had a significant interaction effect for energy expenditure but not respiratory exchange ratio compared to placebo in 16 resistance-trained males. Harty 2020
Compared to decaf placebo, consumption of 200 mg caffiene immediately prior to a 30 minute nap opportunity during a simulated night workshift setting resulted in improved vigilant attention and subjective fatigue in the 45 min post-nap opportunity (n=6). Centofanti 2020
Among 160 primipara pregnant women delivered by caesarean section under spinal anaesthesia there was no difference in time of first flatus and defecation between those chewing gum, drinking coffee, or control groups, while the acupressure group was associated with a reduced time. Kanza 2020
In a randomized controlled trial, consumption of decaffeinated coffee was associated with decreased serum uric acid (SUA). Caffeinated coffee (CC) increased serum xanthine oxidase activity. Uric acid clearance was not affected by either. In non-hyperuricemics, SUA was increased by CC. Towiwat 2020
For non-caffeine users but not habitual users, 100 mg caffeine enhanced odor sensitivity but reduced odor identification in a double-blind study with 40 participants. Stafford 2020
In a meta-analysis of 6 clinical trials, green coffee extract (GCE) reduced fasting blood glucose level but had no effect on insulin levels. At doses greater than 400 mg, GCE supplementation was associated with a decrease in homeostatic model assessment of insulin resistance (HOMA-IR) status. Nikpayam 2019
In a counterbalanced, randomized, double-blind controlled study of 13 men, there was a clear effect of caffeine supplementation on sprinting performance when torque factor and sprint duration are optimized to allow participants to express their highest peak power output. Glaister 2019
In a double-blind, randomized prospective study of 201 healthy volunteers, caffeine intake independently increased blood pressure and calculation speed. Gene polymorphisms may modify limitedly the effect of caffeine intake on hemodynamic parameters in combination with habitual caffeine consumption. Yoshihara 2019
In a crossover, randomized double-blind study of 24 young, healthy, active men, caffeine supplementation demonstrated improvements in mean power and peak power in both concentric and eccentric movement phases during a flywheel half-squat exercise. Castillo 2019
A meta-analysis of 4 controlled trials (n=341) found that the postoperative administration of coffee significantly reduced the time to first bowel movement, first flatus, and tolerance of solid diet, improving GI motility without impact on postoperative morbidity. Gkegkes 2019
In a placebo-controlled double-blind pilot study, ingestion of chlorogenic acid-enriched green coffee bean extract improved arterial stiffness, as assessed by the cardio-ankle vascular index, in 16 healthy Japanese men. Suzuki 2019
A double-blind crossover study of sedentary adults found that caffeine consumption reduced the perceived effort during exercise and increased capacity to tolerate higher intensity exercise for greater duration. Kumar 2019
Caffeine improved attentional cognitive function of participants (n=49) but did not have acute effects on olfactory function. Han 2019
In a randomized controlled trial,moderate amounts of caffeine intake did not affect pattern-reversal visual evoked potential (PR-VEP) parameters in participants. Top Karti 2019
A systematic review found no consistent effect of caffeine administration on neuropsychiatric symptoms in individual patients with dementia. Kromhout 2019
A Swiss prospective randomized controlled trial (n=115) found that coffee intake after elective laparoscopic colorectal resection leads to faster recovery of bowel function. Hasler-Gehrer 2019
A parallel group, randomized non-inferiority trial of laboring pregnant women found that maltodextrin was cleared from the stomach faster than coffee with milk or orange juice. Nascimento 2019
A randomized crossover study (n=15) found that sodium intake did not significantly modulate the impact of regular coffee consumption on blood pressure. Esselink 2019
In 32 young, healthy volunteers, caffeine affected cutaneous microvascular function during rest and during a postocclusive reactive hyperaemia response, and it increased blood pressure and decreased heart rate. Melik 2019
A systematic review of randomized controlled trials found coffee consumption reduced time to defecation after colorectal and gynaecological resection, but had no significant effect after caesarean section. However the quality of evidence was low to moderate. Cornwall 2019
A systematic review of clinical trials suggested that consumption of caffeinated coffee may lead to unfavorable acute effects on glucose metabolism; however an improvement on glucose metabolism was found on long-term follow up. Reis 2019
Acute effects of caffeine ingestion on glycemic indices: A systematic review and meta-analysis of clinical trials. [No abstract] Emami 2019
Meta-analysis of 9 clinical trials indicated that green coffee supplements reduced systolic and diastolic blood pressure in hypertensive patients when administered at dosages of less than 400 mg for 4 weeks. Han 2019
A meta-analysis of 16 randomized controlled trials found supplementation with green-coffee extract for 4wks or longer was associated with significant reduction in BMI but no change in body weight or waist circumference. Greater reduction was seen in individuals with baseline BMI =25?kg/m2. Gorji 2019
Systematic review of randomized controlled trials summarized the effects of hydroxycinnamic acids (HCA) from supplements or foods including coffee on cardiometabolic (CM) risk factors. The effect of HCAs on CM risk factors may be greater in individuals at higher CM risk. Martini 2019
Decaffeinated and caffeinated coffee increased reaction time but not skeletal muscle strength in a prospective, interventional, comparative study of 70 healthy adults. Those drinking caffeinated coffee experienced greater mood improvement than those consuming decaffeinated coffee. Sane 2019
Systematic search and meta-analysis of 10 randomized control trials including 1,237 patients revealed evidence that administration of coffee and diet compared to water and diet significantly decreased time to first bowel movement but did not impact first flatus after colorectal surgery. Hogan 2019
A randomized, double-blind, parallel controlled trial of 150 healthy, overweight people found that consumption of high chlorogenic-acid instant coffee for 12 weeks more effectively lowered visceral fat, abdominal fat, BMI, and waist circumference compared to control coffee. Watanabe 2019
Ingestion of decaffeinated coffee with the addition of isolated caffeine and extra virgin coconut oil, either isolated or combined, does not improve 1600 m running times, nor influence rating of perceived exertion and lactate concentrations in recreational runners. Borba 2019
Consumption of biscuits with antioxidant dietary fiber isolated from spent coffee grounds, both alone and in combination with fructooligosaccharides improved the quality and length of sleep in young adults. Oseguera-Castro 2019
In a randomized, within-subject, crossover trial, consumption of anhydrous caffeine-supplemented coffee did not result in an augmented testosterone response post exercise in strength-trained males. Landry 2019
Assessed muscle strength and endurance in Twenty-eight resistance-trained men under 5 conditions: no-placebo control, placebo control, and with caffeine doses of 2, 4, and 6 mg·kg-1. Grgic 2019
In a double-blind randomized controlled trial administration of a supplement containing Bacopa monniera, Panax quinquefolius, and whole coffee fruit extract improved working memory task performance, associated with a reduction of prefrontal cortex activation, in healthy adults (n=40). Best 2019
A crossover randomized controlled trial of 15 male middle-distance runners found consumption of caffeine 1 hour before an 800-m running time-trial test did not improve performance variables. However, caffeine impaired studied sleep variables. Ramos-Campo 2019
In a 28 day double-blind randomized controlled trial of 71 adults with mild cognitive decline, consumption of coffee cherry extract was associated with reductions in reaction time compared to placebo. Robinson 2019
In a randomized, placebo-controlled study, inhaling coffee fragrance enhanced continuity of attention, quality of memory, and speed of memory, and increased the mood score of alertness in young adults. There were no changes in salivary cortisol level, blood pressure, and heart rate. Hawiset 2019
In a randomized study of 60 obese women aged 30-50 years, a combined therapy of green coffee bean extract supplementation and 8 weeks of elastic resistance band training was associated with reduced obesity and improved cardiometabolic risk scores. Banitalebi 2019
Systematic review of randomized controlled trials and meta-analysis revealed that green coffee bean extract decreased serum total cholesterol and LDL-C and increased HDL-C compared to controls, but had no significant effect on serum trigylcerides. Ding 2019
In a controlled trial, ingesting coffee providing 3 mg·kg-1 of caffeine increased salivary caffeine levels and improved 5 km cycling time trial performance in men and women by a similar magnitude Clarke 2019
In a 24-wk randomized controlled tria, consumption of 4 cups instant regular coffee daily did not change insulin sensitivity, fasting plasma glucose, or biological mediators of insulin resistance compared with placebo, in overweight non-insulin sensitive Chinese, Malay, and Asian-Indian adults. Alperet 2019
In randomized placebo-controlled study, a mixture of Berberis aristata, Elaeis guineensis and decaffeinated green coffee (C. canephora) reduced serum glucose, insulin levels, HOMA-IR, and a measure of steatosis vs. placebo in non-alcoholic fatty liver disease patients with hepatic steatosis. Cossiga 2019
Meta-analysis of 6 randomized controlled trials showed no significant effect of decaffeinated coffee-enriched chlorogenic acid on blood glucose concentration, despite the findings of some recent studies in animals. Faraji 2018
A double-blind, counterbalanced-crossover randomized controlled trial found that both caffeinated and decaffeinated coffee had effects on cognition when compared to placebo. Haskell-Ramsay 2018
A systematic review of trials and epidemiological studies found that consumption of coffee seemed to be associated with change in serum lipoprotein(a), and the effect appeared to be complex and may follow a biphasic time-course. The type of coffee and method of preparation were also pertinent. Penson 2018
A literature review of from human and animal model studies noted that a wide variety of studies have proven that dietary antioxidants, including coffee, may help in regulating intraocular pressure as well as protecting retinal neurons. Pinazo-Duran 2018
In 100 patients who gave birth by elective caesarian section, consumption of coffee after surgery reduced the time to first flatus compared to control, but did not have a significant impact on average time of first defecation, first bowel sound, or mean time of hospital stay of patients. Rabiepoor 2018
Meta-analysis of 2 intervention studies showed that caffeine had no effect on vestibular evoked myogenic potential (a clinical test that evaluates the muscular response of high intensity auditory stimulation) in normal individuals. Souza 2018
Coffee in hypertensive women with asymptomatic peripheral arterial disease: a potential nutraceutical effect. [No abstract] Mattioli 2018
Results of a crossover study of 15 males suggested that reducing the amount of hydroxyhydroquinone (HHQ) facilitates the postprandial fat oxidation effects of chlorogenic acid in coffee. These findings suggest that the inhibition of fat oxidation by HHQ is related to postprandial oxidative stress. Katada 2018
In a double-blind study of 300 healthy young women, Coffea robusta had non-significant beneficial effects on attention, general cognitive ability, and memory. C. arabica had significant effects on sleepiness, attention, general cognitive ability, perhaps due to its higher chlorogenic acids content. Alharbi 2018
In a randomized trial,'slow' coffee metabolizer genotype (AC) participants displayed higher baseline glucose and NEFA than those with 'fast' genotype (AA). Consumption of instant coffee for 12 wk reduced postprandial glycemia and NEFA supression in AC genotypes, with the opposite result in AA. Robertson 2018
A randomized, cross-over single-blind study of 17 healthy men measured the influence of regular coffee, regular coffee with sugar, and decaffeinated coffee on glucose metabolism and incretin hormones. Decaf coffee improved insulin sensitivity without changing incretin hormones levels. Reis 2018
In a single-blind, placebo-controlled study of 10 healthy males, consumption of coffee polyphenols suppressed the deterioration in skin barrier function and skin moisture content induced by sodium dodecyl sulfate treatment, and increased parasympathetic nervous activity. Kagawa 2018
A meta-analysis of randomized placebo-controlled trials investigating caffeine effects on endurance time-trial performance found caffeine had a small but evident effect on endurance performance when taken in moderate doses. Also improved mean power output and and time-trial completion time, overall. Southward 2018
In 2 randomized counterbalanced trials, while coffee improved and stabilized reaction time regardless of recent sleep history, it increased commission errors and only partially reduced omission errors in individuals reporting poor sleep quality. Anderson 2018
In a crossover randomized controlled trial, moderate consumption of soluble green/roasted coffee blend reduced cardivascular risk markers, such as reducing serum lipids, blood pressure and increasing plasma antioxidant capacity, in healthy and hypercholesterolemic subjects. Martínez-López 2018
In a randomly counterbalanced, double-blind, crossover, placebo-controlled study of 12 healthy male endurance runners, caffeinated coffee consumption failed to enhance the time trial performance of an 800-m run compared with decaffeinated coffee consumption. Marques 2018
In 2 double-blind, crossover randomized controlled trials, a supplement containing extracts of white mulberry, white bean, and green coffee, reduced postprandial glucose and insulin levels and postprandial reactive hypoglycemia after a high glycemic meal in healthy subjects. Adamska-Patruno 2018
Reviewed human studies and clinical trials of dietary polyphenols, including those from coffee, as anti-diabetic agents. Cao 2018
In a randomized controlled trial, consumption of coffee did not improve excretion rates of colon capsules after complete colon capsule endoscopy compared to control. Buijs 2018
A double-blind, counterbalanced, cross-over randomized controlled trial with experienced cyclists did not find a significant correlation between caffeine ingestion and improved anaerobic performance. However, individual response many vary. Anderson 2018
A systematic review on the effects of maternal caffeine consumption during breastfeeding on the child yielded insufficient and inconsistent evidence. McCreedy 2018
A meta-analysis of randomized controlled trials through Feb 2017 found that neither caffeinated nor decaffeinated reduced fasting blood glucose levels, compared to placebo/water. Kondo 2018
In 21 nursing home residents with dementia, gradual elimination of afternoon and evening consumption of caffeine led to a significant improvement in sleep scores and apathy, but no significant changes occurred in agitation/aggression, irritability, or aberrant motor behavior. de Pooter-Stijnman 2018
In a single-blinded, 3-stage clinical trial investigating the individual lipid changes in response to coffee drinking, coffee intake was associated with lower levels of specific lysophosphatidylcholine species with with potential impacts on glycerophospholipid metabolism more generally. Kuang 2018
A crossover study of 16 male daytime workers showed that two weeks of consumption of a test beverage containing 300 mg of chlorogenic acids (found abundantly in coffee beans) improved fatigue upon awakening and sleep quality compared to control. Ochiai 2018
A meta-analysis of 6 randomized controlled trials revealed that coffee consumption post-abdominal surgery was associated with reduced time to first defecation, first flatus, first bowel sound, tolerance of solid food and length of hospital stay. Eamudomkarn 2018
A single-blind, randomized controlled trial of healthy Central European adults found that those consuming 500 ml of freshly brewed dark roast coffee per day had decreased mean levels of DNA strand breaks compared to controls, demonstrating DNA protective effect. Schipp 2018
A crossover study of 22 healthy men found that consuming a low antioxidant diet with less than two servings of fruit and vegetables per day and avoiding the intake of cocoa products, coffee and tea resulted in changes in vascular biomarkers compared to their usual diet. Hurtado-Barroso 2018
A systematic review protocol for the effectiveness of coffee for postoperative ileus in patients following abdominal surgery. Kuo 2018
In a randomized parallel-group pilot trial with obese type 2 diabetes patients, consumption for 8 weeks of a diet high in cereal fiber and coffee, but free of red meat, did not improve beta-cell function, but did increase secretion of gastric inhibitory peptide. Karusheva 2018
Results from a single-blind crossover RCT of 37 patients with borderline or stage 1 hypertension suggest that a single intake of coffee with a high content of chlorogenic acids and low content of hydroxyhydroquinone is effective for improving postprandial endothelial dysfunction. Kajikawa 2018
An RCT of 24 volunteers showed that caffeinated and decaffeinated coffee consumption is associated with a more potent effect on arterial stiffness in non-habitual than habitual coffee consumers, whereas caffeine induces comparable changes in both groups. Ioakeimidis 2018
Results from an RCT found that administration of 400mg green coffee extract in patients with metabolic syndrome had an ameliorating effect on high systolic blood pressure, high fasting blood glucose, insulin resistance, and abdominal obesity. Roshan 2018
In a double-blind, cross-over RCT (n=13), consumption of caffeinated coffee was associated with enhanced 1-mile race performance in trained male runners. Clarke 2018
Despite more favorable total mood disturbance scores in those consuming high chlorogenic acid (CQA) coffee, data from this RCT of cyclists (n=15) do not support the chronic use of high CQA coffee in mitigating postexercise inflammation or oxidative stress or improving 50-km cycling performance. Nieman 2018
An investigation of the effect of caffeine intake on fractional flow reserve (FFR) values measured using intravenous adenosine triphosphate before cardiac catheterization. Caffeine intake affected FFR values and their stability, which could not be reversed by an increased ATP dose. Nakayama 2018
A prospective cross-over study of 57 subjects found that use of a chewing gum containing Garcinia cambogia, green coffee extract and L-carnitine may aid in the control over snack intake and reduce hunger sensations. Bobillo 2018
In a controlled trial of 160 healthy subjects, consumption of up to 5 cups of coffee for 8 weeks had no detectable effect on any markers of health measured, including oxidation of DNA and lipids, creatinine, glucose, insulin, cholesterol, triacylglycerides, inflammatory markers, or blood pressure. Shaposhnikov 2018
A crossover, randomized, controlled study in 25 normocholesterolaemic and 27 hypercholesterolaemic men and women aged 18-45 with BMI 18-25 found that consumption of a green/roasted coffee blend reduced blood pressure, glucose and triglyceride levels, and insulin resistance in both groups. Sarriá 2018
Literature review indicated that coffee administered 3-4.5?h before a meal had minimal influence on food and macronutrient intake, while caffeine ingested 0.5-4?h before a meal may suppress acute energy intake. Schubert 2017
Review presented some evidence from epidemiological studies, clinical interventions, and animal and cell studies supporting the cardioprotective effects of dietary polyphenols, such as those in coffee. Murillo 2017
Coffee intake <4 h prior to regadenoson perfusion cardiac magnetic resonance imaging has no effect on stress-induced hyperemia as measured with T1 mapping. van Dijk 2017
Review summarized evidence from clinical trials and observational prospective studies elucidating the beneficial associations between dietary polyphenols (including those from coffee) and prediabetes and type 2 diabetes. Guasch-Ferré 2017
Coffee intake had a significant influence on both acute systolic and diastolic blood pressure but not on pulse arrival time or pulse wave velocity in 30 healthy participants. Ahmaniemi 2017
Results from a double-blind RCT indicated that consumption of a beverage containing 297.8 mg coffee polyphenols daily for 4 weeks significantly improved scaliness and played a role in cutaneous blood flow regulation after cold stress. Ueda 2017
A summary of 15 clinical trials assessing the effect of coffee, caffeine, or other coffee components on inflammatory markers. Data suggest a predominant anti-inflammatory action of coffee but not of caffeine consumption. Caffeine exhibited both pro- and anti-inflammatory responses. Paiva 2017
An RCT of 64 obese women aged 20-45 found that green coffee bean extract combined with an energy-restricted diet affects fat accumulation and lipid metabolism more than diet alone. Haidari 2017
A double-blind, crossover RCT showed that the effects of a caffeine cognition test in an at-home setting revealed similar results as in a controlled setting. Participants showed improved results in the Go-No Go test after caffeine intake. Pasman 2017
In 10 healthy adults, a counterbalanced crossover study showed that consumption of coffee with a relatively high caffeine content induced an acute diuretic effect, while coffee with a low caffeine content did not. Seal 2017
A randomized, placebo-controlled, cross-over study including 12 healthy adults showed that the consumption of caffeinated coffee resulted in a significant improvement in endothelial function, but there was no evidence for benefit regarding glucose metabolism or blood pressure. Boon 2017
In a double-blind, placebo-controlled study of 49 female subjects with mildly xerotic skin, consumption of a test beverage containing coffee polyphenols improved skin properties and microcirculatory function, suggesting CPPs improve skin permeability barrier function and hydration. Fukagawa 2017
A randomized parallel controlled clinical trial of 45 subjects aged 18-22 found that a green coffee bean extract-based mouthwash reduced Streptococcus mutans colony count comparably to chlorhexidine. Yadav 2017
Data from 10 healthy young men suggested that drinking coffee does not increase cerebral pulsatile stress acutely despite an elevation in arterial stiffness in the systemic circulation. Washio 2017
A double-blinded placebo-controlled cross-over intervention study of 9 healthy subjects showed that consumption of 600 mg of chlorogenic acids for 5 days increased fat oxidation during sleep, shortened sleep latency, and did not affect sleep architecture nor adversely affect sleep quality. Park 2017
In a randomized, double-blind, cross-over trial, indirect calorimetry showed that 1-week ingestion of hydroxyhydroquinone-reduced coffee led to higher postprandial fat utilization than that of HHQ-containing coffee. Soga 2017
Review of data from clinical trials published in the last five years on the role of coffee consumption against cardiovascular diseases and their risk factors found that results were equivocal. Further research is needed before definitive recommendations can be made. Di Lorenzo 2017
In 46 overweight participants, consumption of sugar-sweetened coffee greater increased post-prandial plasma glucose and insulin responses compared to orange juice; fat-free, low-fat, and whole milks; or water. All beverages (except water) were standardized to contain 12 g digestible carbohydrate. Li 2017
Results from a double-blind, repeated-measures study of 36 participants indicated that under emotional arousal, caffeine and theanine exert opposite effects on certain attentional processes, but when consumed together, they counteract the effects of each other. Giles 2017
Results from two acute randomized, controlled, crossover human intervention trials in a total 39 healthy male subjects indicate that coffee intake acutely improves human vascular function, an effect, in part, mediated by 5-CQA and its physiological metabolites. Mills 2017
In a randomized study of 241 patients, IV aminophylline and IV caffeine provided rapid, safe reversal of regadenoson-induced adverse effects during SPECT MPI. Orally administered caffeine from coffee appeared similarly effective only for complete reversal. Doran 2017
Results from a comparative, randomized controlled study in 15 participants comparing changes in heart rate, blood pressure, and cardiac QTc interval after consumption of energy drinks, coffee, or water found no differences between beverages. Brothers 2017
A systematic review analyzing evidence from epidemiological and randomized controlled trials on the deleterious effects of coffee and caffeine consumption on sleep. Clark 2017
Results from 4 trials in 7 young, healthy male adults suggested that the combination of coffee intake and repeated bouts of low-intensity exercise enhanced fat oxidation in the period after exercise, better than combinations involving plain hot water or a single bout of exercise of longer duration. Kurobe 2017
Data from a randomized controlled trial of 114 patients found that coffee consumption after total abdominal hysterectomy and systematic paraaortic lymphadenectomy expedites the time to bowel motility and the ability to tolerate food. Güngördük 2017
A double-blinded parallel study with 49 young, healthy subjects found that consumption of caffeinated coffee increased urgency and frequency of urination, especially among those with a history of low coffee intake. Staack 2017
A study protocol for a randomized cross-over trial to define the bioavailability and benefits of coffee bioactive compounds on the basis of different levels of consumption. Mena 2017
In college-age adults, consumption of caffeine improved performance in explicit memory tasks, but not implicit memory tasks, in the early afternoon and late afternoon. Caffeine did not alter memory performance in the mid afternoon. Sherman 2016
In 12 participants with hypertension, ingestion of two or three doses of caffeinated coffee completely blunted the postexercise hypotension (PEH) response, while one dose resulted in partial elimination of the PEH. Souza 2016
A double-blinded randomized crossover clinical trial of patients with chronic heart failure with moderate-to-severe systolic dysfunction and at a high risk for ventricular arrhythmias found that acute ingestion of high doses of caffeine did not induce arrhythmias. Zuchinali 2016
In 42 healthy Iranian men aged 20-40 subjected to partial sleep deprivation, consumption of caffeinated coffee was more adverse for glucose homeostasis compared to consumption of decaffeinated coffee. Rasaei 2016
In a double-blind, randomized, counterbalanced crossover study, neither the ingestion of coffee nor caffeine improved repeated sprint cycling performance in relatively untrained males. Clarke 2016
Systematic review of randomzied controlled trials found that although responses differed depending on polyphenol-carbohydrate combo, polyphenols in foods/beverages (eg, coffee) reduced peak and early-phase glycaemic response and maintained the glycaemic response in later stages of digestion. Coe 2016
A review of 26 human dietary intervention studies (with acute and chronic coffee intake) found that coffee consumption increased glutathione levels and improved protection against DNA damage. The effects on plasma antioxidant capacity, antioxidant enzymes, and protein and lipid damage are unclear. Martini 2016
Proposal of a double-blind randomized placebo-controlled 24 week trial of overweight habitual coffee consumers of Chinese, Malay, and Asian-Indian ethnicity exploring the hypothesis that coffee consumption reduces risk of type 2 diabetes through biological pathways involving insulin sensitivity. Alperet 2016
Prospective analysis of 105 patients indicated that caffeine intake inverted the adenosine effect during stress perfusion cardiac magnetic resonance imaging (CMR) as measured by T1 mapping. T1 reactivity can assess the adequacy of adenosine-induced stress in perfusion CMR. Kuijpers 2016
A randomized double-blind crossover clinical trial found no significant changes in blood pressure or heart rate after participants consumed green coffee extract or guayusa leaf extract. Green coffee extract provoked an increase in epinephrine compared to control, while guayusa provoked a decrease. Krieger 2016
A double-blind study of 43 participants using a non-immersive virtual reality assessment of executive functions found consumption of coffee significantly improved performance in planning, creative thinking, event-, time-, and action-based prospective memory tasks relative to decaffeinated coffee. Soar 2016
When smokers are nicotine deprived, caffeine consumption diminished baseline elevations in pain threshold, but had no effect on pain tolerance, suggesting caffeine consumption can dampen deficits in sensory discrimination related to pain during nicotine deprivation. Baiamonte 2016
A randomized cross-over study found acute doses of chlorogenic acids (5-CGA), polyphenols in coffee, had no effect on blood pressure in healthy adults (n=16). There was no effect on peak flow mediated dilation (FMD), but there were significant improvements in mean post-ischaemic FMD response. Ward 2016
In a randomized, controlled trial, the addition of coffee to polyethylene glycol + ascorbic acid solution reduced the require volume for bowel preparation without reduced efficacy and enhanced patient comfort in coffee drinkers. Jung 2016
Espresso coffee may have a beneficial effect on daytime somnolence in some patients with Parkinson's disease, as demonstrated by a set of multiple single-patient (n-of-1) trials. Ferreira 2016
A randomized, controlled study found that drinking a single cup of coffee does not have a significant impact on the blood pressure of healthy normotensive young adults one hour after consumption. Teng 2016
Evaluated the changes in salivary pH and flow rate after consumption of selected local beverages, including coffee, and estimated their oral clearance time in healthy adults with no caries. Hans 2016
A proposed study protocol for a double-blinded, placebo-controlled, randomized trial evaluating the capacity for caffeine to shorten the duration of postoperative bowel paralysis after colon surgery. Kruse 2016
In a randomized, double-blind, crossover clinical trial of 40 healthy adults, acute coffee consumption in non-stressful conditions activated salivary gastrin and alpha-amylase and blood pressure but not salivary cortisol, indicating activation of sympathetic nervous system. Papakonstantinou 2016
Erratum for: Low-energy diets differing in fibre, red meat and coffee intake equally improve insulin sensitivity in type 2 diabetes: a randomised feasibility trial. [Diabetologia. 2015] [No abstract] Nowotny 2016
In 24-hour abstinent coffee drinkers, belief that one has consumed caffeine affected caffeine withdrawal symptoms, especially cravings, even when no caffeine was consumed. Mills 2016
In a study with 12 healthy young subjects, coffee drinking augmented dynamic cerebral blood flow regulation with cerebral vasoconstriction. Sasaki 2016
In 9 resistance-trained men, coffee and decaffeinated coffee plus caffeine had the ability to improve performance during a resistance exercise protocol. Richardson 2016
In a randomized controlled trial, coffees with different chlorogenic acid (CGA) concentrations each provided bioavailable CGAs and had a positive acute effect on plasma antioxidant capacity, but no effect on blood lipids or vascular function, in healthy adults. Agudelo-Ochoa 2016
Repeated coffee consumption over 8 hours was associated with reduced background DNA strand breakage in healthy male subjects, clearly measurable as early as 2 h after first intake resulting in a cumulative overall reduction by about one-third of the baseline value. Bakuradze 2016
A review of studies on human subjects indicated there is moderate evidence supporting the use of coffee as an ergogenic aid to improve performance in endurance cycling and running. Coffee may be used as a safe alternative to anhydrous caffeine to improve endurance performance. Higgins 2016
A systematic review and meta-analysis of interventional studies did not show a significant effect of caffeine consumption on the occurrence of ventricular premature beats. Zuchinali 2016
In 54 physically active males there were no observed effects from consumption of creatine in combination with caffeine or coffee on performance compared with placebo. Trexler 2016
Neither coffee nor caffeine anhydrous improved strength outcomes more than placebo, while both groups attenuated sprint power reductions to a similar degree in 54 resistance-trained males. Trexler 2016
In a controlled crossover trial of 11 healthy volunteers, there were no differences in glucose or insulin responses between consumption of two coffees (light vs dark roast) with different chlorogenic acid contents. Both increased the insulin response in a glucose tolerance test compared with water. Rakvaag 2016
A randomized crossover study with healthy habitual and non-habitual coffee consumers found no evidence for specific short-term effects of caffeinated espresso on vagal activity in healthy subjects. Instead, consumption of decaffeinated espresso inhibited vagal activity in habitual consumers. Zimmermann-Viehoff 2016
According to a random effects meta-analysis of RCTs, acute caffeine ingestion reduces insulin sensitivity in healthy subjects. Thus, in the short term, caffeine might shift glycemic homeostasis toward hyperglycemia. Shi 2016
A double-blind, crossover study of 14 males using a naturally low-caffeine Arabica coffee variety (Laurina) found that compared to light-roast, dark-roast improved postload glucose metabolism by increasing incretin and insulin secretions, and improved redox balance and increased omega-3 fatty acids. Di Girolamo 2016
In a randomized trial of 72 euhydrated and fasted male subjects, cumulative urine output at 4 hours after injection of 1 L coffee was not different than after consumption of the same amount of still water. Maughan 2016
Review of a double-blind randomized clinical trial which evaluated caffeine intake during pregnancy and found no significant differences in birth weight or length of gestation between women who drank regular coffee and women who drank decaffeinated coffee. Adams 2016
In a randomized prospective-retrospective study, patients given coffee after undergoing resection surgery on the colon or rectum had a shorter time of getting stool in the postoperative period, a shorter hospital stay and lower incidence of postoperative complications, compared to those given tea. Piric 2015
A double-blind randomized cross-over study of 20 healthy, recreationally active adults who were regular caffeine consumers found consumption of Turkish coffee benefited reaction time and improved subjective feelings of energy, but did not improve 5km run time or cognitive function. Church 2015
A prospective, single-center, randomized controlled study of patients scheduled for elective laparoscopic colectomy (n=15) found that coffee consumption after colectomy was safe, and consumption of decaffeinated coffee after the procedure was associated with reduced time to first bowel action. Dulskas 2015
Mobile phone exposure either alone or in combination with caffeine did not alter reaction time or pre-stimulus oscillatory brain activity in a study of 25 participants. Trunk 2015
Results from an uncontrolled study in 16 healthy volunteers showed that consumption of 473 ml coffee containing 240 mg caffeine did not change endothelial function, as measured by a device using digital peripheral arterial tonometry. Molnar 2015
Coffee polyphenol consumption improved postprandial hyperglycemia and vascular endothelial function, which is associated with increased GLP-1 secretion and decreased oxidative stress,compared to placebo, in a randomized, acute, crossover, intervention study with healthy male adults. Jokura 2015
In an assessment-center like setting, cognitive testing in young adults revealed that neither caffeine nor glucose influence cognitive performance, but caffeine improved dispositions such that participants perceive preserved mental energy throughout the test procedure. Ullrich 2015
In a randomized, double-blind, cross-over experiment, although patients with panic disorder panicked after caffeine-challenge, post-caffeine panickers and non-panickers did not differ with respect to the magnitude of the increases in ACTH, cortisol, and DHEAS plasma levels. Masdrakis 2015
In a randomized parallel-group pilot trial of obese patients with type 2 diabetes, both those allocated to consume a high fiber, red meat-free, and high coffee diet and those consuming a low fiber, high red meat, and coffee-free diet experienced similarly improved cardiac vagal function. Ziegler 2015
Results from a non-controlled study of 65 healthy volunteers indicated that neither the consumption of 1 nor 2 cups of coffee increases ventricular repolarization as measured by an electrocardiogram. Molnar 2015
Reviewed clinical and epidemiological data with regards to the putative pharmacological effects of coffee relevant to the pathogenesis of liver fibrosis and cirrhosis. A major assumption made by this review is that the bulk of the effects of coffee consumption are mediated by caffeine. Feld 2015
In a randomized, double-blind cross-over study found no effect of escalating doses of decaffeinated coffee when caffeine remained constant at 100 mg, in healthy overweight males. One standard serving of coffee (2 g) was sufficient to affect glucose metabolism. Robertson 2015
A double-blind, randomized, controlled trial found a significant reduction of reaction times in 2 cognitive tasks after drinking caffeine compared with decaf, in healthy adults. The great inter-individual variability in responses to caffeine may be explained by human genetic polymorphisms. Renda 2015
In 13 healthy non-diabetic men, the consumption of coffee bean polyphenols before a test meal increased the 2-hr postprandial nitric oxide metabolite levels and decreased the 6-hr postprandial urinary 8-epi-prostaglandin F2α levels, ameliorating postprandial endothelial dysfunction. Ochiai 2015
In a single-blind crossover study of 20 novice surgeons performing a simulation of laparoscopic surgery, caffeine consumption had no marked effect on accuracy, but had a negative effect on task economy (hand movements, total path length, and completion time). Quan 2015
Caffeine and green coffee bean extract did not significantly alter postexercise blood glucose concentrations compared with a placebo in a small randomized study of 10 male cyclists. Beam 2015
Assessment of the comparative effects of expected vs. unexpected caffeine ingestion on the respiratory and autonomic responses to caffeine in people prone to the anxiety-provoking effect of caffeine versus low-anxious controls. Pané-Farré 2015
A randomized feasibility trial in 37 obese type 2 diabetic patients found no differences between 2 low-energy dietary interventions. One involved high fiber and coffee and no red meat intake, while the other was low fiber, coffee free, and high in red meat. Nowotny 2015
Critical discussion of both experimental studies and clinical trials investigating the atheroprotective effects of the most relevant dietary polyphenols. Emerging data suggest mechanism by which polyphenolic substances can modulate cellular lipid metabolism. Zanotti 2015
A cluster-randomized educational intervention program focused on preventing low-level headache among German 8th-10th graders characterized coffee consumption as one of a number of preventable risk factors. The probability of headache cessation in the intervention group was 1.77 higher than control. Albers 2015
A randomized controlled trial with overweight persons (n=118) found medium and dark roast coffee blends exerted different cardiometabolic effects, which were small but possibly relevant. Kempf 2015
Data from experimental sessions with 10 healthy volunteers showed acute hyperammonaemia induced an increase in subjective sleepiness and a sustained decrease in vigilance, which are attenuated by the administration of a single espresso coffee. Casula 2015
In a randomized study of healthy men (n=84), daily consumption of 750 ml dark roast coffee for 4 weeks lowered the level of spontaneous DNA strand breaks in peripheral white blood cells compared to daily consumption of water only. Bakuradze 2015
Postural stability of hemiparetic stroke patients related to somatosensory information was improved after intake of caffeine. Kim 2014
In a double-blind pilot randomized controlled trial,38 GERD patients who did not achieve symptoms control with proton pump inhibitors identified coffeeamong food items that frequently induced moderate-severe reactions. Results suggested that elimination of non-tolerated foods reduced GERD symptoms. Caselli 2014
How much coffee is healthy?[No abstract][Article in German] Etter 2014
In a double-blind cross-over randomized controlled trial, adults with untreated high-normal or borderline-elevated blood pressure found treatment with a supplement containing 500mg olive leaf extract, 100mg green coffee bean extract, and 150mg beet powder had no effect on ambulatory blood pressure. Wong 2014
Data from a 7-week pilot intervention study in 8 subjects found moderate consumption of coffee can modulate platelet phosphodiesterases activity and 3',5'-Cyclic AMP concentrations in humans and that this activity was not directly dependent on the caffeine content of coffee. Montoya 2014
A small double-blind, randomized, cross-over trial (n=12) did not find that energy intake, appetite sensations, plasma glucose, nor gastric emptying varied between consumption of decaffeinated coffee, caffeine pills, or their combination. Schubert 2014
Review of evidence from human studies on the effects of coffee consumption in depressive orders revealed a biphasic response in caffeine psychostimulant effect: low to moderate doses may reduce risk or symptoms, while high doses may worsen symptoms. [Article in Italian] Rusconi 2014
In ulcerative colitis patients experiencing acute flare, the CD4+ T compartment shows a distinctly different pattern during treatment with myrrh, chamomile, and coffee charcoal than during treatment with mesalazine, suggesting an active repopulation of regulatory T cells during active disease. Langhorst 2014
In a pilot study, bowel preparations in the mid and distal segments of the small intestine tended to be better in patients who received coffee enemas in addition to ingesting polyethylene glycol (PEG) than in patients who received PEG only (n=34) . Kim 2014
A randomized pilot crossover study performed on healthy subjects comparing the effects of green coffee and black coffee on cardiovascular health observed significant improvements in cardiovascular markers after 2 weeks of consumption of green coffee, but not black coffee. Revuelta-Iniesta 2014
In a double blinded randomized clinical trial, sipping 10 ml of a syrup consisting of 300 g honey and 30 g instant coffee every 3 hours for a week was more effective than syrups containing honey alone or containing a topical steroid, in adults receiving chemotherapy and experiencing oral mucositis. Raeessi 2014
Meta-analysis of 11 randomized controlled trials & 13 observational studies suggested children & adolescents should limit daily caffeine consumption to 2.5 mg kg(-1) body weight day(-1), or 1-2 cups of tea or 1 small cup of coffee per day, to avoid possible increased anxiety or withdrawal symptoms. Ruxton 2014
In double-blind randomized control trial healthy volunteers served coffee with varied chlorgenic acid content, peak plasma concentration and urinary excretion values showed reduced bioavailability of chlorogenic acids associated with the highest dose ingested, when expressed as percentage of intake. Stalmach 2014
A randomized, controlled, double-blind, parallel group study found the use of patented blend IQP-GC-101 (containing standardized extracts of Garcinia cambogia, Camellia sinensis, unroasted Coffea arabica, and Lagerstroemia speciosa) reduced body weight and body fat in overweight Caucasian adults. Chong 2014
In a study of 32 healthy, overweight coffee drinkers randomized to consumption of 5 cups per day of instant caffeinated coffee, decaffeinated coffee, or water, no significant relationship between coffee consumption and circulating irisin levels was found. Peter 2014
In 9 healthy volunteers, gastric acid secretion was less effectively stimulated after administration of a dark roast blend coffee compared to a market blend. The two blends varied in levels of (β) N-alkanoyl-5-hydroxytryptamides, chlorogenic acids, trigonelline, and N-methylpyridinium. Rubach 2014
A systematic review and meta-analysis of 71 controlled studies (n=490,813) evaluating different intervention strategies, including coffee, for the ability to prevent type 2 diabetes. Merlotti 2014
A randomized acute clinical intervention crossover study in healthy, nondiabetic adult men found a single ingestion of coffee polyphenols improved peripheral endothelial function after glucose loading. Ochiai 2014
Comment on: Coffee consumption and risk of prostate cancer: an up-to-date meta-analysis. [Eur J Clin Nutr. 2014] [No abstract] Discacciati 2014
A counterbalanced crossover study of 50 male coffee drinkers found no significant differences across a range of haematological and urinary markers of hydration status when consuming either 4 x 200 mL cups of of caffeinated coffee in one trial or the same quantity of water in the other. Killer 2014
In a prospective controlled study of 116 healthy volunteers, a single dose of 100 mL Turkish coffee caused a significant decrease in subfoveal choroidal thickness in the eye for at least 4 hours after consumption. Vural 2014
In a randomized, controlled, crossover study, coffee consumption attenuated hepatic insulin resistance but not the increase of intrahepatocellular lipids induced by fructose overfeeding. The effect does not appear to be mediated by differences in the caffeine or chlorogenic acid content. Lecoultre 2014
ALiterature review described growing epidemiological and clinical evidence which indicate that coffee consumption reduces severity of non-alcoholic fatty liver disease. Chen 2014
A systematic review of studies on the effect of coffee on liver associated laboratory tests, viral hepatitis, nonalcoholic fatty liver disease (NAFLD), cirrhosis and hepatocellular carcinoma (HCC). Data showed coffee offers protective effects in patients with these conditions. Saab 2014
Fasted subjects treated with a single, 100mg dose of green coffee caffeine powder, grape seed extract powder or whole coffee fruit concentrate powder increased levels of plasma increased levels of by about 31%, 31% and 143%, respectively, compared to baseline. Reyes-Izquierdo 2013
Review of caffeine, a major constituent of coffee, as an analgesic adjuvant with a favourable risk-benefit. Mechanism of action is best explained by antagonism at adenosine receptors. [Article in German] Petersen 2013
Findings of a double-blind acute crossover study of 60 healthy older adults suggested improvements in mood observed when a decaffeinated green coffee blend was consumed, but not improvements in cognitive function, are to some extent attributed to pure chlorogenic acids. Camfield 2013
Caffeine caused a dampening of the pupillary oscillations in well-rested participants with a maximal effect 1.25 h after consumption. A prolonged effect is found if coffee was consumed between 1 and 2 h before the first measurement. Wilhelm 2013
A randomized cross-over study comparing the impact of a low-fat diet, a low-carbohydrate diet, and a Mediterranean-style diet (black coffee for breakfast and the same total-caloric intake as the other two diets for lunch with red wine) on postprandial glucose levels. Fernemark 2013
A study of 13 healthy and 10 diabetic volunteers found coffee does not adversely affect capillary glucose levels following Khalas dates consumption. Alkaabi 2013
In a study of 17 healthy subjects aged 22-44 years, blood pressure was not significantly increased after consuming coffee (instant or natural) with or without caffeine. [Article in Polish] Bielesz 2013
Two randomized, investigator-blind, cross-over studies in healthy stubjects using magnetic resonance imaging to evaluate the effects of 10 different food ingredients, including coffee, on gall bladder emptying. Marciani 2013
In a randomized crossover study Arabic coffee consumption modestly increased the plasma glucose response of dates compared to that of dates consumed with water, in healthy adults (n=10). Insulin levels were not significantly affected. Al-Mssallem
Review discussed evidence from meta-analyses of well-controlled prospective epidemiologic studies and clinical trials that shows, for most healthy people, moderate coffee consumption is unlikely to adversely affect cardiovascular health. Rebello 2013
A double-blind randomized controlled trial of 97 Iranian adults with persistent post-infectious cough found treatment with honey plus coffee to be significantly more effective than prednisone or guaifenesin in reducing mean cough frequency. Raeessi 2013
A meta-analysis study on Coffee consumption and risk of colorectal cancer in humans showed that coffee consumption can significantly decrease the risks of colorectal cancer and colon cancer, especially in Europe and for females. Li 2013
In a randomized double-blinded, placebo-controlled, acute pilot study, a single dose of a polyphenol-rich beverage (containing whole coffee fruit extract) produced statistically significant changes in several blood biomarkers related to antioxidant/anti-inflammatory effects in healthy volunteers. Nemzer 2011
A study on the acute effects of coffee on endothelial function measured by brachial artery flow-mediated dilation in 20 healthy non-obese subjects showed unfavorable cardiovascular effects on endothelial function & in the fasting state, insulin secretion is also reduced. Buscemi 2010
A 12-week, double-blinded, randomized, controlled clinical study evaluated the efficacy and tolerance of a topical, multi-ingredient, polyphenol, high antioxidant skin care system containing Coffea arabica. The product was found to signficantly reduce the appearance of photoaging. Palmer 2010
Evaluated the changes in total antioxidant capacity and aerobic and anaerobic performance induced by supplementation of coffeeberry (CB) formulation for 4 weeks in college athletes. Results showed that CB formulation slightly increased antioxidant capacity. Ostojic 2008
Examination of the association between drinking of green tea or coffee & the risk of pancreatic cancer in a large population-based cohort study with 102137 participants in Japan,support that green tea or coffee consumption does not have a substantial impact on pancreatic cancer risk. Luo 2007
Chlorogenic acids in green coffee bean extract was shown to reduced blood pressure in humans in a placebo-controlled, randomized clinical trial. Watanabe 2006
The effects of green coffee bean extract (GCE) on blood vessels were evaluated in healthy males. The improvement in reactive hyperemia ratio after ingestion of a drink containing GCE suggested an improvement in vasoreactivity by this component. Ochiai 2004
In a clinical trial both Arabica and Robusta oil elevated serum lipid levels in 11 healthy volunteers determining and that diterpenes in coffee does not involve induction of hypothyroidism. Mensink 1995
History of Record
ORIGINAL RESEARCH BY: J. Mohanasundaram, MD, PhD
April 2013
May 2019
LATEST UPDATES BY: Oren Rabinowitz, MSc
December 2020