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PubMed2006

Caffeine content of decaffeinated coffee.

Caffeine is the most widely consumed drug in the world with coffee representing a major source of intake. Despite widespread availability, various medical conditions necessitate caffeine-restricted diets. Patients on certain prescription medications are advised to discontinue caffeine intake. Such admonition has implications for certain psychiatric patients because of pharmacokinetic interactions between caffeine and certain anti-anxiety drugs. In an effort to abstain from caffeine, patients may substitute decaffeinated for caffeinated coffee. However, decaffeinated beverages are known to contain caffeine in varying amounts. The present study determined the caffeine content in a variety of decaffeinated coffee drinks. In phase 1 of the study, 10 decaffeinated samples were collected from different coffee establishments. In phase 2 of the study, Starbucks espresso decaffeinated (N=6) and Starbucks brewed decaffeinated coffee (N=6) samples were collected from the same outlet to evaluate variability of caffeine content of the same drink. The 10 decaffeinated coffee samples from different outlets contained caffeine in the range of 0-13.9 mg/16-oz serving. The caffeine content for the Starbucks espresso and the Starbucks brewed samples collected from the same outlet were 3.0-15.8 mg/shot and 12.0-13.4 mg/16-oz serving, respectively. Patients vulnerable to caffeine effects should be advised that caffeine may be present in coffees purported to be decaffeinated. Further research is warranted on the potential deleterious effects of consumption of "decaffeinated" coffee that contains caffeine on caffeine-restricted patients. Additionally, further exploration is merited for the possible physical dependence potential of low doses of caffeine such as those concentrations found in decaffeinated coffee.

Caffeine↗
PubMed2005

Coffee, tea, and caffeine consumption and incidence of colon and rectal cancer.

BACKGROUND: Frequent coffee consumption has been associated with a reduced risk of colorectal cancer in a number of case-control studies. Cohort studies have not revealed such an association but were limited in size. We explored the association between consumption of coffee and tea and the incidence of colorectal cancer in two large prospective cohorts of women and men. METHODS: We used data from the Nurses' Health Study (women) and the Health Professionals' Follow-up Study (men). Consumption of coffee and tea and total caffeine intake were assessed and updated in 1980, 1984, 1986, 1990, and 1994 among women and in 1986, 1990, and 1994 among men. The incidence of cancer of the colon or rectum was ascertained through 1998. Hazard ratios were calculated using Cox proportional hazards models that adjusted for potential confounders. All tests of statistical significance were two-sided. RESULTS: During almost 2 million person-years of follow-up, 1438 cases of colorectal cancer were observed. Consumption of caffeinated coffee or tea with caffeine or caffeine intake was not associated with the incidence of colon or rectal cancer in either cohort. For both cohorts combined, the covariate-adjusted hazard ratio for colorectal cancer associated with consumption of each additional cup of caffeinated coffee was 0.99 (95% confidence interval [CI] = 0.96 to 1.03). However, participants who regularly consumed two or more cups of decaffeinated coffee per day had a 52% (95% CI = 19% to 71%) lower incidence of rectal cancer than those who never consumed decaffeinated coffee. CONCLUSIONS: Consumption of caffeinated coffee, tea with caffeine, or caffeine was not associated with incidence of colon of rectal cancer, whereas regular consumption of decaffeinated coffee was associated with a reduced incidence of rectal cancer.

Adult↗
PubMed1986

Coffee, caffeine, and serum cholesterol in Japanese men in Hawaii.

The relationship between coffee consumption and serum cholesterol was investigated in a cohort of 5,858 Japanese males born in 1900-1919 and living in Hawaii in 1965 who are currently followed by the Honolulu Heart Program. Data on coffee consumption, other dietary variables from a 24-hour dietary recall, and other potentially confounding variables collected in 1965 were correlated with serum cholesterol at that examination and at examination six years later. The mean coffee and tea consumption was 3.4 and 1.8 cups/day, respectively. Those consuming no coffee had a mean serum cholesterol of 210 mg/dl, while that of those drinking 9+ cups/day was 220 mg/dl (no such relationship was apparent with tea or cola). The relationship of coffee consumption and serum cholesterol with potentially confounding variables including body mass index, cigarette smoking, diastolic blood pressure, alcohol consumption, physical activity index, serum glucose, serum uric acid, education, age, and fat consumption was examined. When these variables were entered into a multiple regression equation with coffee consumption, a significant relationship between coffee consumption and serum cholesterol (p less than 0.001) persisted, as did that between baseline coffee consumption and serum cholesterol six years later (p less than 0.001). There was no significant relationship between tea or cola, the other major caffeine contributors to the diet, and baseline serum cholesterol. Thus, this analysis indicates a significant positive relationship between coffee consumption and serum cholesterol which is not present with other sources of caffeine.

Aged↗
PubMed1995

The effect of coffee on gastric emptying.

The effect of coffee on gastric emptying was addressed in a scintigraphic liquid-phase gastric emptying study in patients with non-ulcer dyspepsia. Ninety-three subjects (56 males, 37 females; mean age 40 years, range 17-77 years) diagnosed as having non-ulcer dyspepsia were enrolled in the study. The baseline study was to drink 500 ml of 5% glucose water and the coffee study was to drink 500 ml of 5% glucose water containing 4 g of regular instant coffee. The two studies were performed on separate days. Fifteen of the 93 subjects were chosen at random to undergo repeated coffee studies for evaluation of reproducibility. Overall the 93 subjects showed accelerated gastric emptying, as measured by half emptying time (T1/2) with coffee compared with baseline (35.7 +/- 10.5 vs 45.0 +/- 23.1 min, P < 0.001). However, 68 (73.2%) subjects showed accelerated emptying (-14.8 +/- 19.5 min), while 25 (26.8%) subjects showed delayed emptying (5.9 +/- 4.5 min) after ingestion of coffee. There was no significant difference in the change in gastric emptying with coffee in duplicate measurements from the 15 subjects who had two coffee studies (P = 0.082). We conclude that coffee accelerates liquid-phase gastric emptying in the majority of patients with non-ulcer dyspepsia.

Adult↗
PubMed1994

Coffee consumption and risk of non-Hodgkin's lymphoma.

There is no adequate information on the carcinogenicity of coffee and, specifically, on a potential association of coffee drinking with non-Hodgkin's lymphoma. Consumption of coffee and other methylxanthine-containing beverages has been researched in a case-control study conducted in northern Italy. A total of 429 cases of incident histologically confirmed non-Hodgkin's lymphoma and 1,157 controls in hospital for acute, non-neoplastic, non-immunological, non-digestive tract diseases were interviewed during their hospital stay. Relative risk (RR) estimates and their 95% confidence intervals (CI), according to consumption of coffee and other methylxanthine-containing beverages, were derived from multiple logistic regression equations including terms for age, sex, study centre, body mass index, alcohol and smoking status. Compared with non-drinkers, the RR was 1.2 (95% CI, 0.8-1.7) for coffee drinkers. No trend in risk emerged with number of cups of coffee consumed/day (RR = 1.1 for one and three cups; RR = 1.2 for two; or RR = 0.9 for four cups/day), or duration of coffee intake (RR = 1.2 for less than 20 years; RR = 1.3 for 21-30 years; and RR = 1.1 for more than 30 years). Similarly, no significant association was observed with consumption of decaffeinated coffee (RR = 0.9) or tea (RR = 1.2). Consumption of cola was associated with a borderline risk (RR = 1.7; 95% CI 1.0-2.7). We found no association between non-Hodgkin's lymphoma and consumption of regular or decaffeinated coffee and tea.

Adolescent↗
PubMed2005

Blood pressure response to chronic intake of coffee and caffeine: a meta-analysis of randomized controlled trials.

PURPOSE: Coffee is a widely consumed beverage and small health effects of substances in coffee may have large public health consequences. It has been suggested that caffeine in coffee increases the risk of hypertension. We performed a meta-analysis of randomized controlled trials of coffee or caffeine and blood pressure (BP). DATA IDENTIFICATION: BP trials of coffee or caffeine published between January 1966 and January 2003 were identified through literature databases and manual search. STUDY SELECTION: A total of 16 studies with a randomized, controlled design and at least 7 days of intervention was selected, comprising 25 strata and 1010 subjects. DATA EXTRACTION: Two persons independently obtained data on sample size, type and duration of intervention, changes in BP and heart rate (HR), and subjects' characteristics for each trial. Meta-analysis was performed using a random-effects model. RESULTS: A significant rise of 2.04 mmHg [95% confidence interval (CI), 1.10-2.99] in systolic BP and 0.73 mmHg (95% CI, 0.14-1.31) in diastolic BP was found after pooling of coffee and caffeine trials. When coffee trials (n = 18, median intake: 725 ml/day) and caffeine trials (n = 7, median dose: 410 mg/day) were analysed separately, BP elevations appeared to be larger for caffeine [systolic: 4.16 mmHg (2.13-6.20); diastolic: 2.41 mmHg (0.98-3.84)] than for coffee [systolic: 1.22 mmHg (0.52-1.92) and diastolic: 0.49 mmHg (-0.06-1.04)]. Effects on HR were negligible. CONCLUSIONS: Regular caffeine intake increases BP. When ingested through coffee, however, the blood pressure effect of caffeine is small.

Adult↗
PubMed1985

The Tromsø heart study: coffee consumption and serum lipid concentrations in men with hypercholesterolaemia: an randomised intervention study.

In a 10 week trial to assess the effects of coffee consumption and coffee brewing methods on serum cholesterol concentrations 33 men with hypercholesterolaemia were randomly assigned to: continue with their usual coffee intake; stop drinking coffee altogether; or stop drinking coffee for five weeks, thereafter drinking either boiled or filter coffee. Cholesterol concentrations fell significantly in all subjects abstaining for the first five weeks compared with subjects not giving up and continued to fall in those abstaining for 10 weeks. Cholesterol concentrations rose again in subjects returning to boiled coffee but remained the same in those returning to filter coffee. Abstention from heavy coffee drinking is an efficient way of reducing serum cholesterol concentrations in men with hypercholesterolaemia. The extent to which the brewing method affects this relation requires further study.

Adult↗
PubMed1999

The effect of chronic coffee drinking on blood pressure: a meta-analysis of controlled clinical trials.

We sought to assess the effect of coffee consumption on blood pressure in humans. Our data sources included a MEDLINE search of the literature published before December 1997, bibliography review, and expert consultation. We selected controlled trials in which coffee consumption was the only difference between the intervention and control groups, mean blood pressure change was reported for each group or period, and treatment lasted for >24 hours. Of 36 studies initially identified, 11 (522 participants) met these inclusion criteria. Information on sample size, study design, participant characteristics (gender, race, age, baseline blood pressure, and antihypertensive medications), and treatment results were abstracted by 3 reviewers using a standardized protocol. Treatment effect of coffee consumption on blood pressure was estimated with the use of a random-effects model. In the 11 trials, median duration was 56 days (range, 14 to 79 days), and median dose of coffee was 5 cups/d. Systolic and diastolic blood pressure increased by 2.4 (range, 1.0 to 3.7) mm Hg and 1.2 (range, 0.4 to 2.1) mm Hg, respectively, with coffee treatment compared with control. Multiple linear regression analysis identified an independent, positive relationship between cups of coffee consumed and subsequent change in systolic blood pressure, independent of age of study participants and study design characteristics. The effect of coffee drinking on systolic and diastolic blood pressure was greater in trials with younger participants. Our findings provide support for a relationship between coffee consumption and higher blood pressure. Trials of coffee cessation of longer duration and in persons with hypertension should be performed.

Adolescent↗
PubMed1993

A study of the impact of Arabic coffee consumption on serum cholesterol.

Consumption of Arabic coffee is commonly practised by Saudi citizens. The present study was conducted to explore the possible relationship between the serum total cholesterol levels and the intake of Arabic coffee. A total of 252 adult Saudi individuals were recruited, of whom 143 were coffee drinkers and 109 did not drink coffee. The study showed that in comparison to the non-coffee drinkers the serum total cholesterol concentration was significantly higher among the coffee drinkers. Furthermore, the level was higher among females than males who were coffee drinkers. The effect of the duration of coffee consumption on the serum total was significant for both sexes (P < 0.001). It is suggested that further studies should be generated in order to address questions related to the issues discussed. At the present time a reduction in coffee consumption by those groups found to be more liable to adverse influence on their serum total cholesterol levels to have a positive influence should be considered.

Adolescent↗
PubMed2002

Increased urinary hydrogen peroxide levels caused by coffee drinking.

Experiments with volunteers in Singapore have demonstrated that coffee drinking increases urinary hydrogen peroxide levels (Long, Halliwell, Free Rad. Res., 32, 463-467 (2000)). We re-examined the effect of coffee drinking of healthy Japanese subjects on urinary hydrogen peroxide levels. A cup of brewed or canned coffee commercially available in Japan generated 120-420 micro mol hydrogen peroxide in incubation in a neutral medium at 37 degrees C for 6 h. The increased levels were higher than those obtained from a cup of green tea extract or a glass of red wine. After the subject drank a cup of coffee, apparent hydrogen peroxide levels (micro mol/g creatinine) in urine collected 1-2 h after coffee drinking increased 3-10-fold compared to the levels before coffee drinking. The increased urinary hydrogen peroxide levels are likely derived mainly from 1,2,4-benzenetriol excreted in urine, because the major component that generates hydrogen peroxide is found to be 1,2,4-benzenetriol, and storing urine collected after coffee drinking increased hydrogen peroxide levels in a time-dependent fashion. Total hydrogen peroxide equivalent levels excreted in 3 h-urine after coffee drinking were estimated to be 0.5-10% that of coffee consumed. A residual amount of hydrogen peroxide may be retained or consumed in human bodies.

Adult↗
PubMed1998

Effect of differently processed coffee on the gastric potential difference and intragastric pH in healthy volunteers.

The gastric irritation potential of orally administered coffee (150 ml) was investigated in four healthy volunteers by continuous measurement of gastric potential difference (GPD) and intragastric pH. Furthermore, serum gastrin concentrations were measured up to 45 min after administration of the coffee. One of the coffees, untreated, had to be compared with a pretreated coffee. The evaluation of the target parameters Reiz-Index, AUB, Pdmax and ttot revealed a significant difference between untreated coffee and specially treated coffee: the improved coffee processing produced significantly less mucosal irritation. Regarding the intragastric pH, no significant differences between the treatments were observed and no stimulation of gastric acid secretion following coffee was measurable. No consistent effect on serum gastrin concentration was seen: two of the four subjects had a steep increase in serum gastrin following administration with a clear difference between the differently processed coffees, whereas the other two subjects showed no change in serum gastrin. The results of this pilot study confirm the findings of former experiments on the reliability of continuous transmural GPD measurement when investigating the mucosal irritation potential of barrier breakers.

Coffee↗
PubMedDate not supplied

Effects of coffees before and after special treatment procedure on cell membrane potentials in stomach cells.

Coffee, one of the most excessively used beverages worldwide, commences the risk of gastroesophageal reflux (GER), which may lead to gastric ulcers and increase the risk of gastric cancer. Many attempts have been made by the coffee industry to diminish the irritating effect on mucosa by means of altering the extraction methods concerning gerbic acids and the roasting processes. This paper describes the effect of differently produced coffees involving two brands of Darboven and two brands of other coffee roasters. The aim of this study was to prove the results of gastric potential measurements we found in literature by using human AGS gastric epithelial cells (human adenocarcinoma). All four coffee extracts tested differentially affected the membrane resting potential of AGS cells. Coffees no. 1 and no. 2 depolarized the cells, presumably by increasing the cation entry into the cytosol. In marked contrast, coffee no. 4 hyperpolarizes the cells, possibly by H(+) extrusion and/or Cl(-) influx, suggesting that this coffee might increase acidity in the stomach, which might negatively affect the stomach, especially in people with gastroesophageal reflux symptoms. Overall, our data suggest that different roasting methods of coffees affect the membrane potentials of AGS stomach cells, resulting in increased influx of H+ possibly resulting in decreased stomach acidity and thus reducing GER. These results are in good accordance with clinical pharmacological results from potential difference measurements in healthy volunteers we found in the literature.

Adenocarcinoma↗
PubMed2006

Additive effects of vertebrate predators on insects in a Puerto Rican coffee plantation.

A variety of studies have established the value of shaded coffee plantations as habitat for birds. While the value of birds as biological controls in coffee has received some attention, the interactions between birds and other predators of insects have not been tested. We used exclosures to examine the effects of vertebrate predators on the arthropods associated with coffee, in particular the coffee leafminer (Leucoptera coffeella) and the flatid planthopper Petrusa epilepsis, in a shaded coffee plantation in Puerto Rico. We used a 2 x 2 factorial design with four treatments: exclusion of birds, lizards, birds and lizards, and control (no exclusion). Abundance of insects > 5 mm increased when birds or both birds and lizards were removed. Birds and lizards had an additive effect for insects < 5 mm and for all insects combined. Coffee leafminers showed a weak response to removal of predators while planthopper abundance increased significantly in the absence of avian predators. Arthropod predators and parasitoids did not differ significantly between treatments. Our findings suggest that vertebrate insectivores have an additive effect on insects in coffee and may help control abundances of some coffee pests. Equally important, we present evidence suggesting that they do not interfere with other known natural enemies of coffee pests.

Animals↗
PubMed1989

Reinforcing effects of caffeine in coffee and capsules.

In a residential research ward the reinforcing and subjective effects of caffeine were studied under double-blind conditions in volunteer subjects with histories of heavy coffee drinking. In Experiment 1, 6 subjects had 13 opportunities each day to self-administer either a caffeine (100 mg) or a placebo capsule for periods of 14 to 61 days. All subjects developed a clear preference for caffeine, with intake of caffeine becoming relatively stable after preference had been attained. Preference for caffeine was demonstrated whether or not preference testing was preceded by a period of 10 to 37 days of caffeine abstinence, suggesting that a recent history of heavy caffeine intake (tolerance/dependence) was not a necessary condition for caffeine to function as a reinforcer. In Experiment 2, 6 subjects had 10 opportunities each day to self-administer a cup of coffee or (on different days) a capsule, dependent upon completing a work requirement that progressively increased and then decreased over days. Each day, one of four conditions was studied: caffeinated coffee (100 mg/cup), decaffeinated coffee, caffeine capsules (100 mg/capsule), or placebo capsules. Caffeinated coffee maintained the most self-administration, significantly higher than decaffeinated coffee and placebo capsules but not different from caffeine capsules. Both decaffeinated coffee and caffeine capsules were significantly higher than placebo capsules but not different from each other. In both experiments, subject ratings of "linking" of coffee or capsules covaried with the self-administration measures. These experiments provide the clearest demonstrations to date of the reinforcing effects of caffeine in capsules and in coffee.

Adult↗
PubMed1989

Coffee drinking in patients with duodenal ulcer and a control population.

The ingestion of plain coffee was compared in 150 duodenal ulcer patients (DU) and 100 control subjects without digestive complaints (C). The DU and C groups were registered in accordance with their daily consumption of coffee: none, 1-100 ml, 101-300 ml, 301-500 ml, and more than 500 ml. Fifty millilitres of coffee as prepared in Brazil contain around 50 mg of a caffeine, which is 2.8 times more than in an equal volume of coffee in the United States. Patients with DU stopped drinking coffee or reduced the volume significantly after symptoms started. There was a significant change in coffee intake at all volume levels except at 1-100 ml. The main reason for the reduction of coffee ingestion was the relationship observed by the patients between the consumption of coffee and dyspeptic complaints. Our results suggest a close correlation between the ulcer-like symptoms and the amount of coffee ingested by patients with duodenal ulcer.

Adolescent↗
PubMed1999

Associations between maternal decaffeinated and caffeinated coffee consumption and fetal growth and gestational duration.

Because of concern about the potential adverse effects of consuming caffeinated beverages during pregnancy, pregnant women may choose to replace caffeinated with decaffeinated coffee. In a population-based study of 7,855 livebirths in California's San Joaquin Valley, we examined the relation of maternal decaffeinated and caffeinated coffee consumption during pregnancy to measures of fetal growth and gestational duration. Mothers answered a questionnaire in the hospital at the time of completing the birth certificate. Compared with women who drank neither decaffeinated nor caffeinated coffee, those who consumed only decaffeinated coffee showed no increased odds of small-for-gestational age birth, low birth weight, or preterm delivery, nor lowered mean birth weight or shortened mean gestational age. Women who consumed caffeinated coffee alone had an adjusted odds ratio of 1.3 [95% confidence limits (CL) = 1.0, 1.7] for preterm delivery, whereas those who consumed both caffeinated and decaffeinated coffee had an adjusted odds of 2.3 (95% CL = 1.3, 4.0). When caffeinated and decaffeinated coffee were considered as continuous variables, we found a reduction in adjusted mean birth weight of -3.0 gm per cup per week (95% CL = -5.9, -0.6) for caffeinated coffee and an increase of +0.4 gm per cup per week (95% CL = -3.7, 4.5) for decaffeinated coffee.

Adult↗
PubMed1992

Coffee and coronary heart disease.

OBJECTIVE: We determined if coffee consumption is associated with an increased risk of developing coronary heart disease. DATA IDENTIFICATION: Articles published between 1966 and August 1991 examining a possible link between coffee and coronary heart disease were identified by a computer-aided literature search (Medline) and by standard bibliographic searches. STUDY SELECTION: All prospective cohort studies providing data on daily coffee consumption and coronary events (acute myocardial infarction and/or coronary death) were included. DATA EXTRACTION: Data from each published article were extracted. Additional unpublished data augmenting those published for one study were also included. Each cohort was categorized by reported daily coffee consumption. Incidence of coronary events at each level of coffee consumption was the primary outcome. RESULTS: Eleven prospective studies were included. The coronary events for subjects consuming little or no coffee (less than or equal to 1 cup per day) were compared with event rates for those consuming greater amounts of coffee. The studies exhibited heterogeneity of results. The typical odds ratios and 95% confidence intervals across studies were estimated by logistic regression analysis. Coffee intake from 1 to 4 cups per day was not associated with any increase in coronary heart disease occurrence compared with 1 cup or less per day (odds ratio, 1.01; confidence interval [0.93, 1.11]). The odds ratios for 4 to 6 and 6 cups or more per day compared with up to 1 cup per day were 1.01 (0.90, 1.12) and 1.09 (0.97, 1.22), respectively. CONCLUSIONS: There is no association between coffee consumption and the occurrence of coronary heart disease. This conclusion holds in the absence of adjustment for other coronary risk factors.

Adult↗
PubMed2004

[Does coffee drinking influence serum uric acid concentration?].

The drinking of coffee, a commonly used beverage, was a subject of many studies, mainly regarded to coffee influence on cardiovascular system. However, only one study indicates that coffee drinking in male adults may lead to decrease in serum uric acid level. Hyperuricaemia is a risk factor of many diseases. The aim of this study was to examine the influence of coffee drinking on serum uric acid concentration. 1955 working persons aged from 18 to 65 years were included into research. There were 571 women among them. We determined energy expenditure during professional work, blood pressure, body mass index, and measured serum levels of uric acid, glucose and creatinine. The amount of coffee and ethanol consumption was evaluated on the ground of an interview. It was showed that persons drinking coffee have lower serum uric acid concentration than non-drinkers, especially among women, who drank more coffee then men. Uricaemia was correlated negatively with number of cups of coffee consumed and positively with body mass index, ethanol consumption and diastolic blood pressure. The author conclude that: 1) among women drinking on an average 10 cups of coffee per week appeared a decrease in serum uric acid concentration and a lower risk of development of hyperuricaemia, 2) elevated serum uric acid concentration is accompanied by elevated blood pressure and increased body mass index.

Adult↗