Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Coffee”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 829 records · Page 46Linked to original sources
PubMed1983

Coffee drinking and risk of bladder cancer.

The relationship between coffee drinking and risk of bladder cancer was assessed with the use of data from a case-control study of bladder cancer. Incident cases (2,982) and general population controls (5,782) were interviewed. Overall, the relative risk (RR) of bladder cancer for subjects who had ever drunk coffee was estimated as 1.4 (95% confidence interval = 1.1-1.8). There was no consistent relation between the RR estimate and the current consumption level. Among men who drank coffee, those who drank more than 49 cupfuls of coffee per week had an apparent excess in risk, but women who drank that much had an apparent deficit in risk.

Adult↗
PubMed1982

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.

Glutathione (GSH) S-transferase is a major detoxification enzyme system that catalyzes the binding of a variety of electrophiles, including reactive forms of chemical carcinogens, to GSH. Green coffee beans fed in the diet induced increased GSH S-transferase activity in the mucosa of the small intestine and in the liver of mice. A potent compound that induces increased GSH S-transferase activity was isolated from green coffee beans and identified as kahweol palmitate. The corresponding free alcohol, kahweol, and its synthetic monoacetate are also potent inducers of the activity of GSH S-transferase. A similar diterpene ester, cafestol palmitate, isolated from green coffee beans was active but less so than was kahweol palmitate. Likewise, the corresponding alcohol, cafestol, and its monoacetate showed moderate potency as inducers of increased GSH S-transferase activity. Kahweol palmitate and cafestol palmitate were extracted from green coffee beans into petroleum ether. The petroleum ether extract was fractionated by preparative normal-phase and reverse-phase liquid chromatographies successively. Final purification with silver nitrate-impregnated thin-layer chromatography yielded the pure palmitates of cafestol and kahweol. The structures were determined by examination of the spectroscopic data of the esters and their parent alcohols and by derivative comparison.

Animals↗
PubMed1981

Effect of coffee ingestion on the left ventricular systolic time intervals at rest, during physical effort and the recovery period.

The investigations were carried out in 50 young healthy men, of whom 20 made an increasing submaximal physical effort on a bicycle ergometer after drinking a 250 ml coffee infusion (20 g of pure natural coffee); the remaining 30 men represented the control group. The left ventricular systolic time intervals (LVSTI) were obtained from polycardiograms by means of the Weissler et al. method. It was found that 20 minutes after coffee drinking the left ventricular ejection time index (LVETI) and LVET/PEP ratio increased whereas the pre-ejection period index (PEPI) and the isovolumic contraction time (ICT) decreased. This improvement of the activity of the heart as a pump which is indirect proof of increased myocardial contractility after drinking coffee was especially noticeable during subsequent phases of physical effort. The recovery period in group 1 was characterized by a reduced PEPI and ICT and increased LVETI and LVETI/PEP ratio as compared with the control group.

Adult↗
PubMed1995

Coffee consumption, alcohol use, and cigarette smoking as determinants of serum total and HDL cholesterol in two Serbian cohorts of the Seven Countries Study.

The associations between serum total and HDL cholesterol and three lifestyle factors--consumption of Turkish coffee, consumption of alcohol, and cigarette smoking--were examined in two Serbian cohorts of the Seven Countries Study. In 1988 and 1989, 319 men from Zrenjanin and Belgrade, 65 to 84 years old and free of myocardial infraction, participated. The men from Zrenjanin were originally working in a large cooperative, and the men from Belgrade were faculty members of the university. HDL cholesterol, alcohol consumption, and cigarette smoking were significantly higher in Zrenjanin than in Belgrade. Serum total cholesterol levels and coffee consumption were not different. ANCOVA showed that serum total cholesterol levels were 8.2% higher (P < .05) in men consuming two small cups of coffee per day compared with abstainers, and this was also seen after adjustment for cigarette smoking, age, body mass index, cohort, and alcohol consumption. In men consuming one or more alcoholic drinks per day (more than 10 g/d alcohol), HDL cholesterol levels were increased by 0.19 mmol/L (15.4%) compared with men consuming no alcohol (P < .001). This association was stronger in the Zrenjanin cohort than in the Belgrade cohort (P < .05). Smoking was not associated with total cholesterol or with HDL cholesterol levels. In Serbian men, boiled Turkish coffee and alcohol consumption are independently associated with serum total and HDL cholesterol levels, respectively.

Adult↗
PubMed1995

Effect of coffee on solid-phase gastric emptying in patients with non-ulcer dyspepsia.

The purpose of this study was to evaluate the effect of coffee on solid phase gastric emptying in patients with non-ulcer dyspepsia (NUD). Twenty-one NUD patients with an endoscopic negative finding or superficial gastritis were included in this study. Radionuclide labeled solid meals were used to assess the gastric emptying times (GET) of the stomach. A control meal was composed of radionuclide solid meal and 500ml 5% of glucose water. The study meal was made from addition of 4g of instant coffee into the control meal. Of the 21 total cases, 1 demonstrated prolonged GET, 6 had shortened GET, and the other 14 showed no significant difference in GET. There were no statistically significant differences (p > 0.05) between the control and the study meal after coffee intake. Our data suggests that there may be some ingredient in coffee that promotes gastric motility, but this effect is counteracted by intestinal feedback, and the net effect is not significant.

Adult↗
PubMedDate not supplied

Determination of free and total carbohydrate profile in soluble coffee.

A liquid chromatographic (LC) method was evaluated for the determination of free and total carbohydrates in soluble coffee. Samples are solubilized in water for free carbohydrates or hydrolyzed with 1.00N hydrochloric acid for total carbohydrates. An aliquot of the sample solution is analyzed on a pellicular anion-exchange polystyrene-divinylbenzene column using pure water as the mobile phase. Carbohydrates are quantitated by a pulsed amperometric detector. All major carbohydrates found in soluble coffee are determined in a single run. The technique allowed the detection of fraudulent addition of coffee husks or parchments as well as cereals or caramelized sugar for the 63 commercial products analyzed. High levels of free mannitol, free fructose, free glucose, sucrose, total glucose, and total xylose are a good indication of adulteration. Data were compared with those obtained from separate enzymatic determinations and from a different LC procedure. A close agreement among the methods was observed. However, the original method was superior in precision and was the only procedure that enabled the quantitation of all major carbohydrates. The technique is, therefore, a very powerful tool for routine analysis and for purity assessment of soluble coffee.

Carbohydrates↗
PubMedDate not supplied

Coffee, tea, tobacco, and cancer of the large bowel.

The impact of tobacco use and coffee and tea intake on the risk of colorectal cancer is unclear. Previous research has suggested that coffee may be protective against these cancers, and investigation regarding tea or cigarette smoking has yielded inconsistent results. To clarify these issues, we evaluated coffee and tea intake and tobacco smoking as risk factors for cancer of the colon and rectum in a population-based case-control study from Stockholm, Sweden. Cases were ascertained from the regional cancer registry, and controls identified through population registers. Subjects completed a questionnaire requesting information regarding foods and beverages consumed, exercise, tobacco use, and personal characteristics. Logistic regression modelling was used to compute odds ratios. A total of 352 cases of colon cancer, 217 cases of rectal cancer, and 512 controls took part. High coffee intake was negatively associated with the risk of colon cancer: the odds ratio for those drinking 6 or more cups per day was 0.55 (95% confidence interval, 0.31-0.96) compared to those drinking one or fewer. There was no association with rectal cancer. For tea, the associations were the opposite: there was no association with colon cancer risk, but the odds ratio for rectal cancer was 0.56 (95% confidence interval, 0.34-0.90) for those drinking 2 or more cups per day compared with those drinking none. Smokers of 11 or more cigarettes per day had a 20 to 30% reduction in the risk of colon and rectal cancer, but these findings were consistent with chance. There was no association of long-term cigarette smoking with risk.

Adenocarcinoma↗
PubMed1994

Correlates of decaffeinated coffee choice.

We sought to identify the illness risk factors associated with consumption of decaffeinated coffee in a sample of 2,677 adults. Women who drank decaffeinated coffee exclusively were more likely than other women to consume vitamin supplements and cruciferous vegetables, to use seat belts routinely, and to exercise regularly. Among men, those who drank decaffeinated coffee exclusively were more likely than others to have a low body mass index and to consume a low-fat diet and cruciferous vegetables. We conclude that people who drink decaffeinated coffee differ from others in ways that might provide information about the risk of illnesses.

Adult↗
PubMed1996

[Asthma to green coffee of environmental origin].

A case of rhinitis and environmental asthma caused by unroasted coffee has been reported in an adolescent living in a building in which there is an installation for roasting coffee. The diagnosis, suggested by the case history, is confirmed by the presence of specific IgE, by the positive result of the skin test using unroasted coffee extract and also of a broncho-provocation test entailing the manipulation of dust from the coffee roasting room. An amelioration of the room and work conditions is recommended.

Adolescent↗
PubMed1996

Teratopharmacological and behavioral effects of coffee in mice.

The possible relationship between coffee exposure during pregnancy and the teratopharmacological effects on the developing neonates was evaluated in albino mice. The body weight of pups of treated dams was significantly affected after birth and as the pups grew, their weight gains were lower compared to controls. This effect was time- and dose-dependent and the perinatal treatment was more effective (F(6) = 5.06, p < 0.02) than the prepartum treatment (F(6) = 3.12, p < 0.05). Body hair appearance and eye opening were delayed in all treated groups and again, the perinatal treatment was more effective and dose-dependent. Almost all indices for "locomotor behavior" were affected by all doses of coffee but only in the perinatally treated groups and the effects were neither time- nor dose-dependent. In the "tube restraint test", the latency to the first bite was decreased and the number of bites was increased in the offspring, while in female offspring the effect was opposite. The body weight of female offspring remained low even in young adult animals (F(6) = 9.89, p < 0.005). The brain weight in males was unaffected but in females it was decreased but only at the dose of 2 mg/kg. The liver and kidney weights of both sexes decreased at the lower doses. The protein content of these organs was also significantly affected by coffee treatment. These results suggest that coffee intake during pregnancy should be limited since it produces significant and long-lasting teratopharmacological and behavioral alterations in the offspring.

Animals↗
PubMed2002

Origin assessment of green coffee (Coffea arabica) by multi-element stable isotope analysis of caffeine.

The delta(13)C(VPDB), delta(2)H(VSMOW) and delta(18)O(VSMOW) values of caffeine isolated from Arabica green coffee beans of different geographical origin have been determined by isotope ratio mass spectrometry (IRMS) using elemental analysis (EA) in the "combustion" (C) and "pyrolysis" (P) modes (EA-C/P-IRMS). In total, 45 coffee samples (20 from Central and South America, 16 from Africa, six from Indonesia, and three from Jamaica and Hawaii) were analysed, as well as three reference samples of synthetic caffeine. Validation was performed by excluding isotope discrimination in the course of sample preparation and determining linear dynamic ranges for EA-P-IRMS measurements. The values for caffeine from green coffee ranged from -25.1 to - 29.9 per thousand, -109 to -198 per thousand, and +2.0 to -12.0 per thousand for delta(13)C(VPDB), delta(2)H(VSMOW), and delta(18)O(VSMOW), respectively. Data evaluation by linear discrimination analysis (LDA) and by classification and regression tree (CART) analysis revealed the delta(18)O(VSMOW) values to be highly significant. Use of LDA on the delta(2)H(VSMOW) and delta(18)O(VSMOW) data from coffee of African and Central/South American provenance led to error rates of 5.7% and 7.7% for adaption and cross validation, respectively.

Journal Article↗
PubMed1996

Electrophoretic clean-up of organic acids from coffee for the GC/MS analysis.

The clean-up presented here includes a free flow field step electrophoresis followed by ultrafiltration. Thus, organic acids can be separated from non-acidic and high-molecular compounds in roasted and instant coffee. The acids are identified by gas chromatography/mass spectrometry after freeze-drying and trimethylsilylation. With the method presented, 31 acids could be identified in commercial roasted coffee blends and in instant coffee, among them for the first time in coffee: 3-hydroxypropionic, 2-oxobutyric, glyceric, 2,4-dihydroxybutyric, 5-hydroxymethylfuran-2-carboxylic and 2-hydroxyglutaric acid.

Journal Article↗
PubMed2004

A molecular method for detection of Aspergillus carbonarius in coffee beans.

Ochratoxin A (OTA) is a carcinogenic and nephrotoxic mycotoxin that has been detected in a variety of food products, including green coffee beans. About 80% of Aspergillus carbonarius strains collected from coffee beans are able to produce OTA on this substrate. The rapid identification of this fungal species would be desirable. RAPD assays were applied to identify amplification products specific for A. carbonarius. One selected fragment, denoted OPX7809, was cloned and sequenced. Based on the nucleotide sequence obtained, specific oligonucleotides (OPX7F809 and OPX7R809) were designed and used as primers for DNA amplification. One amplified band of 809 bp was obtained from A. carbonarius genomic DNA, whereas no amplified fragment from DNA of other Aspergillus species was detected. This PCR analysis was also successfully employed to detect A. carbonarius in coffee beans. This PCR assay could contribute to the early and rapid detection of the potential presence of OTA in coffee samples.

Aspergillus↗
PubMed2005

Inter-simple sequence repeat (ISSR) variation in forest coffee trees (Coffea arabica L.) populations from Ethiopia.

Genetic variation of forest coffee trees (Coffea arabica L.) from four regions of Ethiopia was investigated using inter-simple sequence repeat (ISSR) markers. A total of 160 individuals representing 16 populations were sampled. Eleven ISSR primers amplified a total of 123 fragments of which 31 fragments (25%) were polymorphic. Estimate of total gene diversity (HT), and the coefficient of genetic differentiation (GsT) were 0.37 and 0.81, respectively. This indicates that most of the variability is between populations than within populations. The partitioning of genetic variation into within and between populations based on Shannon's information index also revealed more differentiation between populations (0.80) than within populations (0.20). In the phenogram most of the coffee tree samples were clustered on the basis of their regions of origin but failed to cluster according to their respective populations, which could be attributed to the presence of substantial gene flow between adjacent populations in each region assisted by man in the process of transplantation or by wild animals such as monkeys, which eat the berries and defecate the seeds elsewhere. On the other hand, the inter-regional clustering of some coffee tree samples from Bale and Jimma regions could be due to the transport of coffee seeds across regions and their subsequent planting. Although ISSR markers detected lower polymorphic loci than previously reported results with random amplified polymorphic DNA (RAPD) markers on the same materials, it can be used as an alternative method for molecular characterization of C. arabica populations. The results may provide information to select sites for in situ conservation.

Base Sequence↗
PubMed2003

Ochratoxin A on green coffee: influence of harvest and drying processing procedures.

Ochratoxin A is a metabolite produced by Aspergillus and Penicillium species that is nephrotoxic and possibly carcinogenic to humans. The aim of this study was to evaluate ochratoxin A contamination in green coffee obtained by different harvesting and drying operations and from fruits of different ripening stages in order to identify hazards. The research was directed to coffees from the highland area of Rio de Janeiro state (Brazil), which is traded in the domestic market. Twenty-two out of 54 samples contained ochratoxin A at levels ranging from 0.3 to 160 microg/kg. Ochatoxin A contamination levels between different ripe stage fruits were not significant (P > 0.05). "Varrição" coffee, consisting of fruits that fell from the tree spontaneously and stayed longer on the ground before being harvested, was the most contaminated. Eleven out of 14 samples of varrição coffee were contaminated. Three out of 10 samples from the northwestern region of the state were positive for ochratoxin at levels ranging from 10.1 to 592 microg/kg. The contaminated samples had in common the fact that they were harvested directly from the soil.

Agriculture↗
PubMed2003

Effects of coffee components on the response of GABA(A) receptors expressed in Xenopus oocytes.

The effects of both coffee components and coffee extract on the electrical responses of GABA(A) receptors expressed in Xenopus oocytes were studied by injecting cRNAs of the alpha(1) and beta(1) subunits of the bovine receptors. The aqueous extract of coffee dose-dependently inhibited the GABA-elicited responses, whereas the lipophilic extract of coffee by diethyl ether slightly potentiated it at low doses (0.1-0.4 microL/mL) but showed inhibition at high doses (0.5-0.8 microL/mL). Theophylline inhibited the response in a noncompetitive mechanism (K(i) = 0.55 mM), whereas theobromine and trigonelline hydrochloride inhibited it in a competitive manner, K(i) = 3.8 and 13 mM, respectively. Benzothiazole, catechol, 2,4-dimethylstyrene, guaiacol, 1-octen-3-ol, sotolone, and 2,3,5-trimethylphenol potentiated the responses significantly. Potentiation elicited by guaiacol and sotolone was independent of GABA concentrations, whereas that by 1-octen-3-ol was dependent. When 1-octen-3-ol (100 mg/kg) was orally administered to mice prior to intraperitoneal administration of pentobarbital, the sleeping time of mice induced by pentobarbital increased significantly.

Alkaloids↗
PubMed2005

Chemical discrimination of arabica and robusta coffees by Fourier transform Raman spectroscopy.

This article deals with the potential of Fourier transform (FT) Raman spectroscopy in discrimination of botanical species of green and roasted coffees. There are two species of commercial importance: Coffea arabica (arabica) and Coffea canephora (robusta). It is recognized that they differ in their lipid fraction, especially in the content of the diterpene kahweol, which is present at 0.1-0.3% dry matter basis in arabica beans and only in traces (<0.01%) in robusta. The visual examination of the Raman spectra of the lipid fraction extracted from arabica, robusta and liberica samples shows differences in the mid-wavenumbers region: arabica spectra have two characteristic scattering bands at 1567 and 1478 cm(-1). The spectrum of the pure kahweol shows the same bands. Principal component analysis is applied to the spectra and reveals clustering according to the coffee species. The first principal component (PC1) explains 93% of the spectral variation and corresponds to the kahweol concentration. Using the PC1 score plot, two groups of arabica can be distinguished as follows: one group with high kahweol content and another group with low kahweol content. The first group includes samples coming from Kenya and Jamaica; the second group includes samples from Australia. The main difference between these coffees is that those from Kenya and Jamaica are well-known for growing at a high altitude whereas those ones from Australia are grown at a low altitude. To our knowledge, the application of Raman spectroscopy has never been used in coffee analysis.

Altitude↗
PubMed2004

Free and conjugated biogenic amines in green and roasted coffee beans.

This work reports the composition of arabica and robusta coffees in terms of biogenic amines. The analyses were conducted before and after acid hydrolysis with the aim of the determining both free and conjugated forms in green and roasted coffee beans. The amines (putrescine, cadaverine, serotonin, tyramine, spermidine, and spermine) were determined by reverse-phase high-performance liquid chromatography (RP-HPLC) after derivatization with dansyl chloride. Multivariate analyses were applied in order to evaluate the possible use of these amines as chemical descriptors for arabica and robusta coffees. It was found that putrescine, the main biogenic amine present in the green beans, could be used in the discrimination of the referred species. There is also some evidence that these compounds can be used for discrimination between green coffees subjected to different postharvest processes and that tyramine can be considered a chemical marker for Angolan robustas. The variations in biogenic amine levels after roasts is also discussed, but the statistical significance for species discrimination is reduced.

Analysis of Variance↗