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At least 469 records · Page 26Linked to original sources
PubMed1985

Caffeine degradation and increased ochratoxin A production by toxigenic strains of Aspergillus ochraceus isolated from green coffee beans.

The growth and ochratoxin A production of Aspergillus ochraceus strains S-235-100 and IFM 0458, which were isolated from green coffee beans and glutinous rice, respectively, were examined in yeast extract-sucrose (YES) medium containing 0.1 to 1.0% caffeine. The mycelial growth and ochratoxin A formation of strain IFM 0458 was inhibited by caffeine at concentrations over 0.1%, and ochratoxin A was not produced at caffeine levels of 0.5% and 1.0%. Contrary to this, A. ochraceus strain S-235-100 produced a larger amount of ochratoxin A in the presence of 0.5% and 1.0% caffeine when grown on YES medium, reaching a maximum after 15 to 20 days of incubation. The formation of ochratoxin A by nine additional strains of A. ochraceus, three strains of A. elegans and one strain of A. sclerotiorum isolated from green coffee beans was determined on rice and ground green coffee media. A significant degree of degradation of caffeine in the green coffee medium was demonstrated with cultures of nine A. ochraceus isolates from green coffee beans. Most of these isolates showed the potential to grow on moist green coffee beans and to produce a significant amount of ochratoxins.

Aspergillus↗
PubMed1978

[Determination of diterpene glycosides in coffee (author's transl)].

The determination of 3'O-beta-D-glucopyranosyl-2'-O-isovaleroyl-2beta-(2-desoxy-atractyligenin)-beta-D-glucopyranoside (KA 1) and 2-O-beta-d-glucopyranosyl-atractyligenin (KA II) in coffee was carried out by liquid/liquid-partition, column chromatography, thin layer chromatography, and photometry. In robusta and arabusta green coffees KA I levels were below the limit of detection, in arabica green coffees between 170 and 460 mg/kg. KA II was present in robusta green coffees between 10 and 45 mg/kg, in arabusta green coffee at about 60 mg/kg, in arabica green coffees between 290 and 340 mg/kg. During roasting these values are reduced, but not during commercial extraction.

Chromatography, Liquid↗
PubMed1986

Comparative inhibition of coffee-induced gastric acid secretion employing misoprostol and cimetidine.

Six healthy subjects (three men, three women) were studied to compare the effects of misoprostol and cimetidine on coffee-induced gastric secretion. Gastric secretion was measured after a 12-hr fast according to the Hobsley method, employing phenolsulfonphthalein (PSP) as a marker. Each subject was studied on three occasions separated by at least one week: as control, basal gastric secretion was measured followed by sample collection after oral placebo and then coffee; basal gastric secretion was measured followed by sample collection after 200 micrograms of misoprostol and then coffee; basal gastric secretion was measured followed by 300 mg [corrected] of cimetidine and then coffee. The order of treatment was randomized. Basal gastric secretion collection, sample collection, and the administration of coffee were carefully standardized. Titratable acidity; acid output; and sodium, potassium, chloride, and PSP concentrations were measured in each sample to assess hydrogen ion secretion, pyloric losses, and duodenogastric reflux. Mathematical corrections were available for the last. Results confirmed that coffee is associated with a marked rise in titratable acidity, peak acid output (PAO), and volume with a modest fall in mean gastric pH. Both misoprostol and cimetidine lowered titratable acidity, compared with placebo (P = 0.03). Mean PAO was reduced by both misoprostol and cimetidine in a similar manner, and there was a significant difference between the three treatment groups (P = 0.02). These findings document and confirm the antisecretory effect of a single oral dose (200 micrograms) of misoprostol on gastric secretion.

Adult↗
PubMed1992

Behavioral economics of drug self-administration. IV. The effects of response requirement on the consumption of and interaction between concurrently available coffee and cigarettes.

In behavioral economics, consumption of a reinforcer is determined by its price and by the price of other available reinforcers. This study examined the effects of price manipulations on the consumption of concurrently available coffee and cigarettes. During fifteen 4-h sessions, coffee and cigarettes were concurrently available according to fixed-ratio (FR) schedules of reinforcement. After consumption stabilized under a fixed ratio 100 for both reinforcers, the response requirement for each reinforcer was varied separately (i.e., FR 100, 1000 and 2500), while the response requirement for the other reinforcer was kept at 100. Increasing the FR value decreased coffee and cigarette consumption to a similar degree. Also, as the price for cigarettes increased (and consumption decreased), coffee consumption decreased; however, as the price of coffee increased, cigarette consumption did not change. These results indicate that for this setting the reinforcing effects of cigarettes and coffee were comparable but interacted asymmetrically. These findings when analyzed and quantified via economic concepts of own-price and cross-price elasticity illustrate the viability of using behavioral economics to examine drug self-administration in a choice paradigm.

Adolescent↗
PubMed2004

Coffee consumption and incidence of impaired fasting glucose, impaired glucose tolerance, and type 2 diabetes: the Hoorn Study.

AIMS/HYPOTHESIS: Coffee contains several substances that may affect glucose metabolism. The aim of this study was to evaluate the relationship between habitual coffee consumption and the incidence of IFG, IGT and type 2 diabetes. METHODS: We used cross-sectional and prospective data from the population-based Hoorn Study, which included Dutch men and women aged 50-74 years. An OGTT was performed at baseline and after a mean follow-up period of 6.4 years. Associations were adjusted for potential confounders including BMI, cigarette smoking, physical activity, alcohol consumption and dietary factors. RESULTS: At baseline, a 5 cup per day higher coffee consumption was significantly associated with lower fasting insulin concentrations (-5.6%, 95% CI -9.3 to -1.6%) and 2-h glucose concentrations (-8.8%, 95% CI -11.8 to -5.6%), but was not associated with lower fasting glucose concentrations (-0.8%, 95% CI -2.1 to 0.6%). In the prospective analyses, the odds ratio (OR) for IGT was 0.59 (95% CI 0.36-0.97) for 3-4 cups per day, 0.46 (95% CI 0.26-0.81) for 5-6 cups per day, and 0.37 (95% CI 0.16-0.84) for 7 or more cups per day, as compared with the corresponding values for the consumption of 2 or fewer cups of coffee per day (p=0.001 for trend). Higher coffee consumption also tended to be associated with a lower incidence of type 2 diabetes (OR 0.69, CI 0.31-1.51 for >/=7 vs </=2 cups per day, p=0.09 for trend), but was not associated with the incidence of IFG (OR 1.35, CI 0.80-2.27 for >/=7 vs </=2 cups per day, p=0.49 for trend). CONCLUSIONS/INTERPRETATION: Our findings indicate that habitual coffee consumption can reduce the risk of IGT, and affects post-load rather than fasting glucose metabolism.

Blood Glucose↗
PubMed2006

Coffee, tea and caffeine consumption in relation to osteoporotic fracture risk in a cohort of Swedish women.

INTRODUCTION: Consumption of coffee and tea, and total intake of caffeine has been claimed to be associated with osteoporotic fracture risk. However, results of earlier studies lack consistency. METHODS: We examined this relation in a cohort of 31,527 Swedish women aged 40-76 years at baseline in 1988. The consumption of coffee, caffeinated tea and the intake of caffeine were estimated from a self-administered food frequency questionnaire (FFQ). Multivariate-adjusted hazards ratios (HRs) of fractures with 95% confidence intervals (95% CIs) were estimated by Cox proportional hazards models. RESULTS: During a mean follow-up of 10.3 years, we observed 3,279 cases with osteoporotic fractures. The highest (>330 mg/day) compared with the lowest (<200 mg/day) quintile of caffeine intake was associated with a modestly increased risk of fracture: HR 1.20 (95% CI: 1.07-1.35). A high coffee consumption significantly increased the risk of fracture (p for trend 0.002), whereas tea drinking was not associated with risk. The increased risk of fracture with both a high caffeine intake and coffee consumption was confined to women with a low calcium intake (<700 mg/day): HR 1.33 (95% CI: 1.07-1.65) with > or =4 cups (600 ml)/day of coffee compared to <1 cup (150 ml)/day. The same comparison but risk estimated for women with a high propensity for fractures (> or =2 fracture types) revealed a HR of 1.88 (95% CI: 1.17-3.00). CONCLUSIONS: In conclusion, our results indicate that a daily intake of 330 mg of caffeine, equivalent to 4 cups (600 ml) of coffee, or more may be associated with a modestly increased risk of osteoporotic fractures, especially in women with a low intake of calcium.

Adult↗
PubMed2001

Origin, diversity and evolution of NBS-type disease-resistance gene homologues in coffee trees (Coffea L.).

The majority of plant disease-resistance genes (R-genes) isolated so far encode a predicted nucleotide-binding site (NBS) domain. NBS domains related to R-genes show a highly conserved backbone of amino acid motifs, which makes it possible to isolate resistance gene analogues (RGAs) by PCR with degenerate primers. Multiple combinations of primers with low degeneracy, designed from two conserved motifs in the NBS regions of R-genes of various plants, were used on genomic DNA from coffee trees, an important perennial tropical crop. Nine distinct classes of RGAs of the NBS-like type, representing a highly diverse sample, were isolated from Coffea arabica and C. canephora species. The analysis of one coffee RGA family suggested point mutations as the primary source of diversity. With one exception, coffee RGA families appeared to be closely related in sequence to at least one cloned R-gene. In addition, deduced amino acid sequences of coffee RGAs were identified that showed strong sequence similarity to almost all known non-TIR (Toll/Interleukin 1 Receptor)-type R-genes. The high degree of similarity between particular coffee RGAs and R-genes isolated from other angiosperm species, such as Arabidopsis, tomato and rice, indicates an ancestral relationship and the existence of common ancestors. The data obtained from coffee species suggests that the evolution of NBS-encoding sequences involves the gradual accumulation of mutations and slow rates of divergence within distinct R-gene families, rather than being a rapid process. Functional inferences drawn from the suggested pattern of evolution of NBS-type R-genes is also discussed.

Amino Acid Sequence↗
PubMed1990

Coffee consumption and serum lipids: a randomized, crossover clinical trial.

PURPOSE: The purpose of this study was to determine the effect of consuming three or more cups of filter-brewed coffee per day on levels of serum lipids. SUBJECTS AND METHODS: A prospective, randomized crossover clinical trial was performed. Twenty-one healthy white male subjects completed the trial, and consumed an average of 3.6 cups of coffee a day. Data were evaluated by analysis of variance for repeated measures and t-test for paired means. RESULTS: No effect of coffee consumption on serum total cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, or apolipoprotein B was found. Diet, creamer use, and cigarette use as well as group assignment and time factors were controlled for in the analysis. CONCLUSION: We found no effect of moderate consumption of filter-brewed coffee on serum levels of atherogenic lipids. This study supports previous work that filtered coffee has no adverse effect on serum lipids. This has far-reaching implications given the widespread use of coffee and the current concern over coronary risk factors.

Adult↗
PubMed1991

Coffee during pregnancy: a reproductive hazard?

Coffee is consumed in large quantities worldwide and any adverse effects would likely have important public health consequences. Because of the widespread exposure to coffee and other caffeine-containing beverages and because teratogenic effects of caffeine have been recorded in several species since 1960, women are concerned that there may be reason to limit their intake of coffee when pregnant. Several human studies on birth defects have been conducted and the overall results do not implicate coffee as a likely human teratogen. However, there is some evidence that consumption of three or more cups of coffee per day may have a modest effect on lowering infant birth weight. Studies of coffee consumption and increased rates of spontaneous abortion and delayed time to conception are inconsistent and conclusions cannot yet be drawn.

Abnormalities, Drug-Induced↗
PubMed1987

Coffee and cholesterol in epidemiological and experimental studies.

Twenty-two cross-sectional studies involving 130,000 persons from 8 different countries have reported their findings on the association between coffee consumption and cholesterol levels. Results of these reports display a variety of trends in the association between coffee intake and serum cholesterol concentrations: 8 (36%) studies demonstrated a significant positive association in both sexes, and 5 (23%) studies showed no association in men or women. In 3 other reports where both sexes were included, significant positive association was observed only in women. The remaining 6 investigations examined only men with 4 (18%) reporting a significant correlation between coffee and cholesterol. This unexplained incongruity of cross-sectional data points to a relationship between coffee and cholesterol in some populations, which needs to be further explored. In addition, HDL cholesterol levels appeared unrelated to coffee intake in the 11 studies in which it was measured. The 7 available human experiments showed the same low level of agreement in the results among small numbers of volunteers. Experiments involving different brewing methods suggest that a major part of the cholesterol-increasing effect can be explained by different brewing methods. A critical assessment of the published reports leads to the conclusion that the data are insufficient to warrant public health admonitions against coffee drinking, but that it may be of clinical importance in some hypercholesterolemic individuals.

Cholesterol↗
PubMed1990

Coffee, caffeine and hemostasis: results from two randomized studies.

The influence of coffee and caffeine consumption on hemostatic factors was studied in 2 randomized trials. Both studies were conducted in young, healthy adults. In the first study, 107 participants were randomly allocated to one or 3 intervention groups, drinking filtered coffee, boiled coffee or no coffee at all, respectively, for a period of 9 weeks. In the second study, 69 subjects received either 4-6 tablets containing 75 mg caffeine or the same amount of placebo tablets, while using decaffeinated coffee. In this double-blind study caffeine intake from any other source was not allowed. Blood samples for hemostatic factors were obtained at baseline and after 9 weeks of intervention. The findings indicate no effect of coffee consumption on fibrinogen, clotting factor VII activity, factor VIII antigen, protein C and protein S and also no effect of caffeine consumption on fibrinogen and factor VII activity.

Adult↗
PubMed1990

Dose-dependent effect on serum cholesterol and apoprotein B concentrations by consumption of boiled, non-filtered coffee.

The effects of boiled coffee (BC) and filtered coffee (FC) on serum lipoproteins were compared in 41 healthy subjects whose serum cholesterol concentration was less than 7 mmol/l. The subjects consumed in random order BC and FC for 4-week periods in a crossover design. The individual daily consumption ranged from 2 to 14 cups (mean 5.7 cups per day) and was similar during both study periods. The serum total and LDL-cholesterol and apoprotein B concentrations were higher (P less than 0.001) and HDL-cholesterol lower (P less than 0.05) after BC than after FC. Bodyweight, apoprotein A-I and triglycerides remained unchanged. In the 16 subjects who consumed coffee less than 5 cups per day the difference in serum total cholesterol between the BC and FC periods was non-significant (P = 0.16). The differences in serum total cholesterol and LDL-cholesterol between the periods showed significant linear correlations with the amount of coffee consumed daily (r = 0.52, P less than 0.001 and r = 0.33, P less than 0.05, respectively) but no association was found between the difference in HDL-cholesterol and the amount of coffee (r = 0.14, P = 0.39). The results indicate a dose-dependent increasing effect on serum total and LDL-cholesterol and apoprotein B concentrations of boiled coffee.

Adult↗
PubMed1987

Boiled coffee increases serum low density lipoprotein concentration.

The effects of boiled coffee, filtered coffee, and tea on serum lipoprotein lipids and apoproteins were compared in 42 middle-aged hypercholesterolemic subjects (21 men and 21 women). The subjects consumed the beverages, eight cups a day, in random order during successive 4-week periods with 2-week run-in intervals in a crossover design. The diet was kept unchanged. Statistically significant differences were found between the periods in serum total cholesterol (P less than .0001 ANOVA), LDL cholesterol (P less than .01), and apoprotein B (P less than .01) levels. All differences were due to significantly higher levels during boiled coffee as compared with filtered coffee and tea. No statistically significant differences were found between the filtered coffee and tea periods. There were no differences in serum VLDL cholesterol or triglyceride, HDL cholesterol, and apoprotein A-I concentrations between the periods. Consumption of boiled coffee thus increased the concentration of low density lipoprotein in the serum without affecting its lipid-protein composition. The effect seemed to be determined by the method of brewing.

Apolipoproteins↗
PubMed1979

Mutagens in coffee and tea.

Coffee prepared in the usual way for drinking contains a substance(s) that is mutagenic to Salmonella typhimurium TA100 without mammalian microsomal enzymes. One cup of coffee (200 ml) contains mutagen(s) inducing 1.4-4.6 X 10(5) revertants under standard conditions. Instant coffee too is mutagenic to TA100 and one cup of instant coffee prepared from 1 g of coffee powder and 200 ml of water induced 5.6-5.8 X 10(4) revertants of TA100. Caffeine-free instant coffee also has similar mutagenicity. Addition of microsomal enzymes abolished the mutagenicity. Black tea, green tea and Japanese roasted tea were also mutagenic to TA100 without S9 mix and one cup of these teas prepared in the ordinary way produced 1.7-3.8 X 10(4) revertants of TA100. Black tea and green tea were also mutagenic to TA98 in the presence of S9 mix after treatment with a glycosidase from Aspergillus niger, hesperidinase. This type of mutagen in one cup of black tea induced 2.4 X 10(5) revertants of TA98.

Coffee↗
PubMed1985

Characteristics of major mutagenicity of instant coffee.

Detailed quantitative studies on the mutagenicity of methylglyoxal showed that its contribution to the total mutagenicity of instant coffee on S. typhimurium TA100 was minor although we reported previously (Kasai et al., 1982) that its contribution to the mutagenicity of freshly brewed coffee was about 50%. Cysteine suppressed the mutagenicity of methylglyoxal and of methylglyoxal when added to instant coffee, but did not affect the mutagenicity of coffee itself. Catalase suppressed most of the mutagenicity of coffee, but not that of methylglyoxal or of methylglyoxal added to coffee.

Catalase↗
PubMed1986

Suppressive effects of coffee on the SOS responses induced by UV and chemical mutagens.

SOS-inducing activity of UV or chemical mutagens (AF-2, 4NQO and MNNG) was strongly suppressed by instant coffee in Salmonella typhimurium TA1535/pSK1002. As decaffeinated instant coffee showed a similarly strong suppressive effect, it would seem that caffeine, a known inhibitor of SOS responses, is not responsible for the effect observed. The suppression was also shown by freshly brewed coffee extracts. However, the suppression was absent in green coffee-bean extracts. These results suggest that coffee contains some substance(s) which, apart from caffeine, suppresses SOS-inducing activity of UV or chemical mutagens and that the suppressive substance(s) are produced by roasting coffee beans.

4-Nitroquinoline-1-oxide↗
PubMed1995

Inhibitory effects of coffee on transplacental genotoxicity in mice.

Experiments were carried out to ascertain whether or not coffee can modulate the genotoxicity of transplacentally active genotoxins/carcinogens. Coffee was orally administered to Swiss albino mice (gestation, 15-16 days), 90 min before exposure to cyclophosphamide (CPH), N-nitrosodiethylamine (DEN), N-nitroso-N-ethylurea (ENU) and mitomycin C (MMC). At the end of the treatment, the induction of micronucleated polychromatic erythrocytes (MnPCEs) was evaluated in the fetal liver (FL), fetal blood (FB) and maternal bone marrow (MBM). The results of this transplacental micronucleus test showed a consistent trend which suggests that the administration of coffee instead of water (control) can significantly inhibit the genotoxic effects of CPH, DEN, ENU and MMC in the FL and FB. When the fetal cells were evaluated either 22 and 28 h after CPH treatment, or 24 and 48 h after MMC treatment, there was no evidence for a significant interaction between the sampling time and the inhibitory effect of coffee (two-factor ANOVA). However, a significant interaction was observed between sampling time and the inhibitory effects of coffee when the fetal cells were sampled 24 and 40 h after DEN treatment (two-factor ANOVA). Coffee was also effective in significantly inhibiting the genotoxicity of CPH, ENU and MMC in the MBM. The differential response of fetal and maternal target cells was evident from this study.

Analysis of Variance↗
PubMed1990

Inhibition by coffee of nitrosourea-mediated DNA damage in mice.

Oral administration of coffee at doses ranging from 150 mg to 1 g per kg body weight significantly decreased endogenously formed nitrosourea-mediated DNA damage in bone marrow as well as in colon epithelial cells in mice that had simultaneously received oral administration of methylurea and sodium nitrite. Since coffee (1 g/kg body weight) did not decrease DNA damage when administered orally together with performed methylnitrosourea, it was hypothesized that coffee inhibits nitrosation in the stomach of mice. The lowest effective level of coffee, when compared on the basis of body weight, corresponds to a human intake of about 5 cups of coffee. Both chlorogenic acid (150 mg/kg body weight) and premelanoidins (1 g/kg body weight), which occur as ingredients in, or are formed during roasting of, coffee, were shown to inhibit nitrosourea-induced DNA damage in mice.

Administration, Oral↗