Caffeinated Coffee Research Articles

Assessment of CYP1A2 enzyme activity in relation to type-2 diabetes and habitual caffeine intake.

BackgroundCoffee consumption is a known inducer of cytochrome P450 1A2 (CYP1A2) enzyme activity. We recently observed that a group of type-2 diabetes patients consumed more caffeine (coffee) on a daily basis than non-type-2 diabetes controls. Here, we investigated whether type-2 diabetes cases may metabolize caffeine faster than non-type-2 diabetes controls.MethodsTo estimate CYP1A2 enzyme activity, an established marker of caffeine metabolism, we quantified the paraxanthine/caffeine concentration ratio in saliva in 57 type-2 diabetes and 146 non-type-2 diabetes participants in a case–control field study. All participants completed validated questionnaires regarding demographic status, health and habitual caffeine intake, and were genotyped for the functional -163C > A polymorphism of the CYP1A2 gene.ResultsIn the diabetes group, we found a larger proportion of participants with the highly inducible CYP1A2 genotype. Furthermore, the paraxanthine/caffeine ratio, time-corrected to mitigate the impact of different saliva sampling times with respect to the last caffeine intake, was higher than in the control group. Participants who reported habitually consuming more caffeine than the population average showed higher CYP1A2 activity than participants with lower than average caffeine consumption. Multiple regression analyses revealed that higher caffeine intake was potentially an important mediator of higher CYP1A2 activity.ConclusionsEstimated CYP1A2 enzyme activity, and thus speed of caffeine metabolism, was higher in our type-2 diabetes group; this was possibly due to higher intake of caffeine, a known inducer of CYP1A2 enzyme activity. Given the fairly small sample sizes, the results need to be considered as preliminary and require validation in larger populations.Electronic supplementary materialThe online version of this article (doi:10.1186/s12986-016-0126-6) contains supplementary material, which is available to authorized users.

High Sensitivity and Fast Oxidation of Caffeine in Coffee and Theophylline at Nanostructured Electrodes

AbstractSignificantly higher than previously reported sensitivity was achieved in the electrochemical determinations of caffeine (CA) and theophylline (TP) at a nanostructured carbon fiber electrode (CFE) sensor by fast scan voltammetry (FSV), where apparent catalysis of the oxidation was observed. For CA the oxidation was reversible and the oxidation potential in aqueous solutions was similar to the potentials reported from cyclic voltammetry (CV) in aprotic solvents, indicating similar oxidation pathways, forming CA radicals. For TP, the reversible oxidation potential was higher, in agreement with TP structure. Formal potentials in aqueous solutions that have been previously unavailable from electrochemistry of CA and TP were thus obtained. In the determinations of CA and TP, sensitivity and linear dynamic range (LDR) in FSV were 1.84 mA cm−2 µM−1 and 0.20–22.0 µmol L−1 and 1.46 mA cm−2 µM−1 and 0.50–30.0 µmol L−1, respectively. FSV determination of CA in coffee sample is demonstrated and the results are in agreement with the results obtained by HPLC‐UV.

Does caffeine intake and coffee consumption associate with endometrial cancer among postmenopausal women in America using NHANES 2003–2012?

Background: In 2015, it has been estimated that 54,870 new cases of endometrial cancer will be diagnosed and about 10,170 women will die from it in United States. Previous studies suggested that high levels of coffee consumption may be associated with reduced risk of endometrial cancer among women ages 50–71. Although caffeine is a major ingredient of coffee, one study stated this inverse association does not differ according to caffeine content (regular coffee/decaffeinated coffee). However, the specific measurement of caffeine intake was not clear in that previous study. This study tries to investigate endometrial cancer risk in relation to caffeine intake and coffee consumption.

Effect of Coffee and Caffeine Ingestion on Resistance Exercise Performance.

Richardson, DL and Clarke, ND. Effect of coffee and caffeine ingestion on resistance exercise performance. J Strength Cond Res 30(10): 2892-2900, 2016-The aim of the present study was to determine the effect of ingesting caffeine dose-matched anhydrous caffeine, coffee, or decaffeinated coffee plus anhydrous caffeine during resistance exercise on performance. Nine resistance-trained men (mean ± SD: age, 24 ± 2 years; weight, 84 ± 8 kg; height, 180 ± 8 cm) completed a squat and bench press exercise protocol at 60% 1 repetition maximum until failure on 5 occasions consuming 0.15 g·kg caffeinated coffee (COF), 0.15 g·kg decaffeinated coffee (DEC), 0.15 g·kg decaffeinated coffee plus 5 mg·kg anhydrous caffeine (D + C), 5 mg·kg anhydrous caffeine (CAF), or a placebo (PLA). Felt arousal and rating of perceived exertion (RPE) were used to assess perceptual variables and heart rate (HR) to assess physiological responses between trials. There were significant differences in total weight lifted for the squat between conditions (p < 0.01; (Equation is included in full-text article.)= 0.54) with a greater amount lifted during D + C compared with DEC (p < 0.01), CAF (p ≤ 0.05), and PLA (p ≤ 0.05) conditions. Total weight lifted during the COF condition was significantly greater than that lifted under PLA (p < 0.01), although not significantly greater than the amount of weight lifted during the DEC condition (p = 0.082). No significant differences were observed in total weight lifted in the bench press protocol between conditions (p = 0.186; (Equation is included in full-text article.)= 0.17). Significant differences in HR (p < 0.01; (Equation is included in full-text article.)= 0.39) but not RPE (squat: p = 0.690; (Equation is included in full-text article.)= 0.07; bench press: p = 0.165; (Equation is included in full-text article.)= 0.18) and felt arousal (p = 0.056; (Equation is included in full-text article.)= 0.24) were observed between conditions. Coffee and decaffeinated coffee plus caffeine have the ability to improve performance during a resistance exercise protocol, although possibly not over multiple bouts.

Methotrexate intolerance in the treatment of rheumatoid arthritis (RA): effect of adding caffeine to the management regimen.

The aim of this study was to investigate the effect of caffeine on the symptoms of methotrexate (MTX) intolerance in patients with RA. The follow-up patients with RA seen over a period of 11months were included in this work. The degree of MTX intolerance, if present, was classified as 'moderate' and 'severe'. Those with intolerance were advised caffeine (coffee or dark chocolate) synchronised with the MTX dose. The effect was assessed as 'very good', 'good' or 'none'. Among 855 patients seen during this period, 313 (36.6%) did not have any MTX intolerance, 542 (63.4%) patients had some degree of MTX intolerance, 422 (77.8%; 49.3% of the total patients) had 'minimal' intolerance not requiring any intervention. The remaining 120 (22.1%) of the 542 (14% of the total 855) patients had 'moderate' or 'severe' MTX intolerance. Among these, 55% had complete relief of symptoms and were able to continue taking the advised dose of MTX; 13.3% had partial improvement and continued taking MTX but only with antiemetics; 7.5% were minimally better but were somehow managing; 10% were complete caffeine failure without any relief; 14.2% did not like caffeine (coffee or dark chocolate) and did not want to take it. Caffeine relieved the symptoms of MTX intolerance in 55% and partial relief in 13% of the patients. A significant number of patients did not like to take caffeine (coffee or dark chocolate). It is of note that northern part of India is primarily a tea-drinking population where coffee is not a favourite drink.

Engineering a microbial platform for de novo biosynthesis of diverse methylxanthines

Engineered microbial biosynthesis of plant natural products can support manufacturing of complex bioactive molecules and enable discovery of non-naturally occurring derivatives. Purine alkaloids, including caffeine (coffee), theophylline (antiasthma drug), theobromine (chocolate), and other methylxanthines, play a significant role in pharmacology and food chemistry. Here, we engineered the eukaryotic microbial host Saccharomyces cerevisiae for the de novo biosynthesis of methylxanthines. We constructed a xanthine-to-xanthosine conversion pathway in native yeast central metabolism to increase endogenous purine flux for the production of 7-methylxanthine, a key intermediate in caffeine biosynthesis. Yeast strains were further engineered to produce caffeine through expression of several enzymes from the coffee plant. By expressing combinations of different N-methyltransferases, we were able to demonstrate re-direction of flux to an alternate pathway and develop strains that support the production of diverse methylxanthines. We achieved production of 270μg/L, 61μg/L, and 3700μg/L of caffeine, theophylline, and 3-methylxanthine, respectively, in 0.3-L bench-scale batch fermentations. The constructed strains provide an early platform for de novo production of methylxanthines and with further development will advance the discovery and synthesis of xanthine derivatives.

Self-aspiration sampling extractive electrospray ionization mass spectrometry (EESI-MS) for high-throughput analysis of liquid samples.

Extractive electrospray ionization mass spectrometry (EESI-MS) was invented as a typical ambient mass spectrometry method (AMS) and has been used for analyzing complex liquid samples. Here, we designed a Venturi effect-based self-aspiration sampling device and applied it to the EESI-MS for high-throughput analysis of liquid sample. A special concentric nebulizer was designed and employed to produce a suction force for the direct aspiration of liquid samples, followed by ionization and detection. This sample aspiration process was explained and optimized using computational fluid dynamics (CFD) analysis. Experiment data were recorded to exhibit the sensitivity, memory effect, inter-day reproducibility, throughput, and applicability of the self-aspiration sampling EESI-MS. The limit of detection (LOD) of this method was determined as 4.5×10(-10) g/mL (S/N=3) for caffeine, and the sample throughput and relative standard deviation (RSD) for full scan mode can reach 0.67 samples/s and 4.76%, respectively. Even for MS/MS mode, the frequency can still be kept at 0.4 samples/s (RSD=4.71%). Inter-day RSD examined in 1week was below 10% for the signal of characteristic fragment ions of reserpine. Moreover, based on this method, the amount of caffeine in instant coffee was determined as 4.7%. This device was also proven to be suitable for the protein/peptide analysis. These experiment results, especially the amazing results on sample throughput and inter-day RSD, suggest that we provide a valuable device which can be used for the direct high-throughput qualitative/quantitative mass spectrometry analysis of real liquid samples in ambient. Copyright © 2016 John Wiley & Sons, Ltd.

Caffeine metabolism rate influences coffee perception, preferences and intake

Several factors – genetic, demographic and environmental – contribute to individual differences in sensitivity to the pharmacological effects of caffeine. Caffeine metabolism influences coffee consumption, but its effect on bitterness perception in, and preference for, coffee is unknown.This study explores the possible relationship between caffeine metabolism rate and coffee preferences and consumption habits. In addition, the extent to which caffeine metabolism interacted with variations in bitterness perception was investigated. Caffeine metabolism rate was assayed by competitive immuno-enzymatic assay in one-hundred thirty-five coffee consumers who provided saliva samples after 12h caffeine abstinence and at 30 and 90min after ingestion of caffeine (100mg). A caffeine metabolism index (CmI) was computed as the ratio between the amount of residual caffeine in saliva 60min after the adsorption peak and the amount of caffeine at the adsorption peak corrected with the baseline. Ninety-one subjects were selected to investigate the relationships between inter-individual variation in caffeine metabolism, bitterness perception and coffee preference. Subjects rated liking for, and sourness, bitterness and astringency of, six unsweetened and freely sweetened coffee samples varying in roasting degree, caffeine content and bitterness. They also rated the bitterness of six caffeine and six quinine (equi-intense) solutions. Finally, subjects choose coffee to drink on the basis of a label (strong vs balanced flavor) both after caffeine abstinence and after no restrictions on caffeine intake. The CmI was strongly associated with the frequency of daily coffee consumption. Subjects with lower CmI gave higher bitterness ratings than other subjects for both coffee and caffeine solutions, but not for quinine solutions. They also added more sugar to the coffee samples. Following caffeine abstinence, all subjects chose the “strong flavor” coffee, while without caffeine restrictions, subjects with lower CmI preferentially tended to choose the “balanced flavor” coffee. These results provide the first link between caffeine metabolism and bitterness perception, and to the use of sugar to modify coffee bitterness.

Quantitative determination of caffeine in coffee by chemiluminescent method

Quantitative determination of caffeine in coffee by chemiluminescent method

Demographics, Health, and Risk Behaviors of Young Adults Who Drink Energy Drinks and Coffee Beverages.

Objective: The present study investigates risk behaviors, sleep habits, and mental health factors associated with caffeinated beverage use in young adults. Materials and Methods: Students from a midsize private university (n = 159) completed a 15-minute anonymous questionnaire, including questions on risk behaviors, sleep habits, alcohol, and caffeine consumption. We compared behaviors between the top ∼15% ("high end") of energy drink users (≥3/month) and coffee users (≥16/month) to those with less frequent or no caffeine consumption. Results: Caffeine consumption was frequent among young adults. In the last month, 36% of students had an energy drink, 69% had coffee or espresso, and 86% reported having any caffeine; however, the majority of students were unaware of the caffeine content in these beverages. High-end energy drink consumers reported more risk-taking behaviors (increased drug and alcohol use and less frequent seat belt use), sleep disturbances (later bedtimes, harder time falling asleep, and more all-nighters), and higher frequency of mental illness diagnoses than those who consumed fewer energy drinks. In contrast, the frequency of most risk behaviors, sleep disturbances, and mental illness diagnoses was not significantly different between the high-end and general population of coffee drinkers. Conclusion: Students with delayed sleep patterns, mental illness, and higher frequency of substance use and risk behaviors were more likely to be regular energy drink users but not regular coffee drinkers. It is unclear whether the psychoactive content in energy drinks results in different behavioral effects than just caffeine in coffee, and/or different personality/health populations are drawn to the two types of beverages.

Evaluation of Caffeine Consumption in Subjects Undergoing Evaluation for Sleep Disordered Breathing

Background: Consumption of caffeinated beverages, typically, coffee, tea, and soft drinks, is very common in the general community. Patients with sleep disordered breathing (SDB) may consume excessive caffeinated beverages to alleviate sleepiness. In this study, we examined if there is an association between SDB and caffeine consumption in an Australian sleep clinic population. Methods: This was an observational study conducted in consecutive subjects who underwent a polysomnography study in our sleep laboratory. Caffeine use was quantified as the number of cups of coffee or tea consumed per day. Soft drink consumption was quantified as either low (<500 mL/day) or high (≥500 mL/day). Daytime sleepiness was assessed using the Epworth Sleepiness Scale. Results: Data were available for analysis in 102 subjects (mean age 57 years; 54% male). Seventy-seven percent of subjects stated that they consumed one or more cups of coffee per day (77%), 51% stated that they consumed one or more cups of tea per day, and 43% stated that they regularly drank soft drinks per day. There was no correlation between the apnea–hypopnea index and self-reported coffee (r = 0.049, p = 0.63), tea (r = −0.003, p = 0.097), and soft drink consumption (r = 0.008, p = 0.935). Conclusions: Caffeine use is common among patients with SDB. However there is no relationship between the severity of SDB and caffeine consumption. Identifying excessive caffeine use may assist physicians in the management of the adverse cardiovascular effects of caffeine and untreated SDB.

Investigating the effects of caffeine on executive functions using traditional Stroop and a new ecologically-valid virtual reality task, the Jansari assessment of Executive Functions (JEF©)

ObjectiveCaffeine has been shown to have effects on certain areas of cognition, but in executive functioning the research is limited and also inconsistent. One reason could be the need for a more sensitive measure to detect the effects of caffeine on executive function. This study used a new non-immersive virtual reality assessment of executive functions known as JEF© (the Jansari Assessment of Executive Function) alongside the ‘classic’ Stroop Colour-Word task to assess the effects of a normal dose of caffeinated coffee on executive function. MethodUsing a double-blind, counterbalanced within participants procedure 43 participants were administered either a caffeinated or decaffeinated coffee and completed the ‘JEF©’ and Stroop tasks, as well as a subjective mood scale and blood pressure pre- and post condition on two separate occasions a week apart. JEF© yields measures for eight separate aspects of executive functions, in addition to a total average score. ResultsFindings indicate that performance was significantly improved on the planning, creative thinking, event-, time- and action-based prospective memory, as well as total JEF© score following caffeinated coffee relative to the decaffeinated coffee. The caffeinated beverage significantly decreased reaction times on the Stroop task, but there was no effect on Stroop interference. ConclusionThe results provide further support for the effects of a caffeinated beverage on cognitive functioning. In particular, it has demonstrated the ability of JEF© to detect the effects of caffeine across a number of executive functioning constructs, which weren’t shown in the Stroop task, suggesting executive functioning improvements as a result of a ‘typical’ dose of caffeine may only be detected by the use of more real-world, ecologically valid tasks.

Discussion of causes and consequences of sleepiness among college students, 2014.

Discussion of causes and consequences of sleepiness among college students, 2014.

Effects of Coffee and Caffeine Anhydrous Intake During Creatine Loading.

The purpose of this study was to determine the effect of 5 days of creatine (CRE) loading alone or in combination with caffeine anhydrous (CAF) or coffee (COF) on upper-body and lower-body strength and sprint performance. Physically active males (n = 54; mean ± SD; age = 20.1 ± 2.1 years; weight = 78.8 ± 8.8 kg) completed baseline testing, consisting of 1 repetition maximum (1RM) and repetitions to fatigue with 80% 1RM for bench press and leg press, followed by a repeated sprint test of five, 10-second sprints separated by 60-second rest on a cycle ergometer to determine peak power (PP) and total power (TP). At least 72 hours later, subjects were randomly assigned to supplement with CRE (5 g of CRE monohydrate, 4 times per day; n = 14), CRE + CAF (CRE +300 mg·d of CAF; n = 13), CRE + COF (CRE +8.9 g of COF, yielding 303 mg of CAF; n = 13), or placebo (PLA; n = 14) for 5 days. Serum creatinine (CRN) was measured before and after supplementation, and on day 6, participants repeated pretesting procedures. Strength measures were improved in all groups (p ≤ 0.05), with no significant time × treatment interactions. No significant interaction or main effects were observed for PP. For TP, a time × sprint interaction was observed (p ≤ 0.05), with no significant interactions among treatment groups. A time × treatment interaction was observed for serum CRN values (p ≤ 0.05) that showed increases in all groups except PLA. Four subjects reported mild gastrointestinal discomfort with CRE + CAF, with no side effects reported in other groups. These findings suggest that neither CRE alone nor in combination with CAF or COF significantly affected performance compared with PLA.

Coffee, caffeine and non-alcoholic fatty liver disease?

We read with interest the meta-analysis [Shen et al. 2016] in Therapeutic Advances in Gastroenterology regarding the association between caffeine and non-alcoholic fatty liver disease (NAFLD). The authors analysed separately the associations of (1) caffeine from ‘regular coffee’, which has been described elsewhere as ‘filtrated coffee’ [Anty et al. 2012], and (2) ‘total caffeine’, which included all coffee types, including espresso, and non-coffee caffeine (e.g. tea and soda). The authors found that ‘regular coffee caffeine’ but not ‘total caffeine’ was inversely associated with NAFLD fibrosis severity, and that neither was associated with NAFLD prevalence. Coffee is a complex mixture of biologically active compounds, including caffeine, chlorogenic acid, cafestol and kahweol. These compounds possess anti-oxidative and anti-fibrotic properties and may protect against a range of liver diseases, including fibrosis, cirrhosis and hepatocellular carcinoma [Saab et al. 2014]. Caffeine is thought to prevent fibrosis by antagonism of adenosine receptor A2a [Feld et al. 2015], which inhibits hepatic stellate cells: the primary mediators of hepatic fibrosis [Wang et al. 2014]. Therefore, it is surprising that the meta-analysis found an inverse association between NAFLD hepatic fibrosis severity and ‘regular coffee caffeine’ but not ‘total caffeine’. One possible explanation for this is that a compound in regular coffee other than caffeine is responsible. An equally plausible explanation is that no association between ‘total caffeine’ and NAFLD fibrosis severity was found because the data in the meta-analysis was unadjusted for confounders, such as type 2 diabetes mellitus (T2DM) and body mass index (BMI). This was apparent in an additional sensitivity analysis we performed on these data, which involved rerunning the meta-analysis while excluding the individual studies one at a time to examine their influence on the pooled association. When we excluded the study by Bambha and colleagues [Bambha et al. 2014], we found a statistically significant association between ‘total caffeine’ and NAFLD hepatic fibrosis severity. However, when we included the study by Bambha and colleagues, the association was null, as reported in the meta-analysis. This is paradoxical since Bambha and colleagues reported that the sole measured source of caffeine (i.e. ‘coffee’ described as ‘coffee {unspecified}’ in the meta-analysis) was actually inversely associated with fibrosis, but only after adjustment for confounders. Unfortunately, the adjustment was not incorporated into the meta-analysis because ‘total caffeine’ was calculated from raw unadjusted coffee consumption. Another notable finding from the meta-analysis is the lack of an association between either ‘regular coffee caffeine’ or ‘total caffeine’ and NAFLD prevalence. The risk of NAFLD is increased in T2DM. Observational studies report inverse associations between coffee and T2DM [Ding et al. 2014]. The mechanism of action is thought to be largely mediated by chlorogenic acid, which improves glucose metabolism by inhibiting gut absorption and gluconeogenesis [Ding et al. 2014]. Chlorogenic acid is present in regular coffee, so a protective effect against diabetes and, thus, reduced NAFLD prevalence might be expected. The lack of an association may reflect the study designs (e.g. cross-sectional and case control) which provide low levels of evidence (e.g. due to selection/information bias and lack of temporality). However, above all it underscores the need for robust randomized trials to investigate the effects of coffee on liver disease and other health outcomes.

Placebo caffeine reduces withdrawal in abstinent coffee drinkers.

Expectancies have been shown to play a role in the withdrawal syndrome of many drugs of addiction; however, no studies have examined the effects of expectancies across a broad range of caffeine withdrawal symptoms, including craving. The purpose of the current study was to use caffeine as a model to test the effect of expectancy on withdrawal symptoms, specifically whether the belief that one has ingested caffeine is sufficient to reduce caffeine withdrawal symptoms and cravings in abstinent coffee drinkers. We had 24-h abstinent regular coffee drinkers complete the Caffeine Withdrawal Symptom Questionnaire (CWSQ) before and after receiving decaffeinated coffee. One-half of the participants were led to believe the coffee was regular caffeinated coffee (the 'Told Caffeine' condition) and one-half were told that it was decaffeinated (the 'Told Decaf' condition). Participants in the Told Caffeine condition reported a significantly greater reduction in the factors of cravings, fatigue, lack of alertness and flu-like feelings of the CWSQ, than those in the Told Decaf condition. Our results indicated that the belief that one has consumed caffeine can affect caffeine withdrawal symptoms, especially cravings, even when no caffeine was consumed.

Higher Caffeinated Coffee Intake Is Associated with Reduced Malignant Melanoma Risk: A Meta-Analysis Study.

BackgroundSeveral epidemiological studies have determined the associations between coffee intake level and skin cancer risk; however, the results were not yet conclusive. Herein, we conducted a systematic review and meta-analysis of the cohort and case-control studies for the association between coffee intake level and malignant melanoma (MM) risk.MethodsStudies were identified through searching the PubMed and MEDLINE databases (to November, 2015). Study-specific risk estimates were pooled under the random-effects model.ResultsTwo case-control studies (846 MM patients and 843 controls) and five cohort studies (including 844,246 participants and 5,737 MM cases) were identified. For caffeinated coffee, the pooled relative risk (RR) of MM was 0.81 [95% confidential interval (95% CI) = 0.68–0.97; P-value for Q-test = 0.003; I2 = 63.5%] for those with highest versus lowest quantity of intake. In the dose-response analysis, the RR of MM was 0.955 (95% CI = 0.912–0.999) for per 1 cup/day increment of caffeinated coffee consumption and linearity dose-response association was found (P-value for nonlinearity = 0.326). Strikingly, no significant association was found between the decaffeinated coffee intake level and MM risk (pooled RR = 0.92, 95% CI = 0.81–1.05; P-value for Q-test = 0.967; I2 = 0%; highest versus lowest quantity of intake).ConclusionsThis meta-analysis suggested that caffeinated coffee might have chemo-preventive effects against MM but not decaffeinated coffee. However, larger prospective studies and the intervention studies are warranted to confirm these findings.

Coffee Consumption and Coronary Heart Diseases: A Mini-Review

Background: Coffee contains thousands of chemical compounds such as chlorogenic acid, caffeine, potassium, niacin, magnesium and tocopherols. Only caffeine in coffee shows pharmacological effects. Based on relevant studies, caffeine in coffee has many side effects such as increasing blood pressure, homocysteine, plasma renin; catecholamine and arrhythmia, which are considered as risk factors for coronary heart diseases (CHD). Several epidemiological studies have investigated this association which conflict each other. Materials and method: The current research was conducted based on articles published in medical journals from 2000 to 2014 applying the PubMed database from which 56 articles were selected. Results: According to the research, coffee can affect the risk of myocardial infraction. Furthermore, coffee’s effect on blood pressure depends on the duration of coffee consumption. Coffee can increase homocysteine concentration which is one of the risk factors for coronary heart diseases. Conclusion: It seems that coffee can affect coronary heart diseases, but these effects depend on many factors too, consisting genetic polymorphism.

Coffee and caffeine consumption and the risk of hypertension in postmenopausal women

The associations of coffee and caffeine intakes with the risk of incident hypertension remain controversial. We sought to assess longitudinal relations of caffeinated coffee, decaffeinated coffee, and total caffeine intakes with mean blood pressure and incident hypertension in postmenopausal women in the Women's Health Initiative Observational Study. In a large prospective study, type and amount of coffee and total caffeine intakes were assessed by using self-reported questionnaires. Hypertension status was ascertained by using measured blood pressure and self-reported drug-treated hypertension. The mean intakes of caffeinated coffee, decaffeinated coffee, and caffeine were 2-3 cups/d, 1 cup/d, and 196 mg/d, respectively. Using multivariable linear regression, we examined the associations of baseline intakes of caffeinated coffee, decaffeinated coffee, and caffeine with measured systolic and diastolic blood pressures at annual visit 3 in 29,985 postmenopausal women who were not hypertensive at baseline. We used Cox proportional hazards models to estimate HRs and their 95% CIs for time to incident hypertension. During 112,935 person-years of follow-up, 5566 cases of incident hypertension were reported. Neither caffeinated coffee nor caffeine intake was associated with mean systolic or diastolic blood pressure, but decaffeinated coffee intake was associated with a small but clinically irrelevant decrease in mean diastolic blood pressure. Decaffeinated coffee intake was not associated with mean systolic blood pressure. Intakes of caffeinated coffee, decaffeinated coffee, and caffeine were not associated with the risk of incident hypertension (P-trend > 0.05 for all). In summary, these findings suggest that caffeinated coffee, decaffeinated coffee, and caffeine are not risk factors for hypertension in postmenopausal women.

The Determination of Caffeine Level of Wolaita Zone, Ethiopia Coffee Using UV-visible Spectrophotometer

Coffee is an important commodity culturally, commercially and economically in the world. Because of its consumption in most countries in the world, it is important to investigate the exact amounts of its chemical constituents. Caffeine is one of the main components of coffee that affect the quality of coffee. In this research, rapid, simple, accurate, reproducible and cheap UV-Vis spectrometer was used for the quantification of caffeine in coffee and dichloromethane was used as a solvent for the coffee samples taken from Wolaita zone of five woredas. The results of this research show that the amount of caffeine of the coffee samples ranged from (450.13 to 579.60 (mg/L). The amounts of caffeine in Bolso Bomba coffee is the greatest, of all the other coffee samples studied in Wolaita Zone. On the other hand, Kindo Koisha and that of Bolso sore coffee has the least caffeine content compared to the other coffee samples measured. The caffeine content of Sodo Zuria coffee and Humbo coffee samples has an average amounts of caffeine.