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Ochratoxin A in Brazilian roasted and instant coffees.

Thirty-four samples of roast and ground coffee, 14 samples of instant coffee and two samples of decaffeinated instant coffee were collected in markets and supermarkets in the city of Campinas, Brazil, and analysed for ochratoxin A using immunoaffinity columns for clean-up and HPLC with fluorescence detection for quantification. The limit of detection was 0.2 ng/g ochratoxin A. Twenty-three samples of ground and roast coffee were found to be contaminated with the toxin at levels ranging between 0.3 and 6.5 ng/g. The average concentration in all 34 samples was 0.9 ng/g. All samples of instant coffee contained ochratoxin A at levels ranging from 0.5 to 5.1 ng/g, with an average figure of 2.2 ng/g. Roast and ground coffee is the type of coffee most used by Brazilians for the preparation of the beverage. Considering that an average Brazilian adult takes five cups of coffee per day, which corresponds to 30 g of roast and ground coffee, the probable daily intake of ochratoxin A by a 70 kg adult would be 0.4 ng/kg bw, which is far below the current Provisional Tolerable Daily Intake of 14 ng/kg bw for ochratoxin A as set by the Codex Alimentarius. To study the transfer of ochratoxin A into coffee brew, the beverage was prepared by two methods: (a) the drip method and (b) the Brazilian country style method. No significant difference was observed between the two methods in terms of extraction of the toxin using five contaminated samples containing between 0.8 and 6.5 ng/g ochratoxin A. The drip method extracted 86 +/- 15% and the Brazilian country style 74 +/- 20% of the ochratoxin A initially present in the roast and ground coffee.

Brazil↗

Research on the origin, and on the impact of post-harvest handling and manufacturing on the presence of ochratoxin A in coffee.

The major risk factors and processing steps that can lead to contamination of green coffee with ochratoxin A (OTA) have been identified. Surveys of the green coffee production chain indicate that Aspergillus ochraceus and A. carbonarius are the most potent OTA producers on coffee. Both have been successfully grown in vitro on green coffee and coffee cherries, respectively, producing high amounts of OTA (5-13 mg kg(-1)). The so-called dry processing of coffee, which is cherry drying, was identified as one of the steps during which OTA formation can take place, particularly under humid tropical conditions. Cherries contain sufficient amounts of water to support mould growth and OTA formation during the initial 3-5 days of drying on the outer part of the cherries. Not surprisingly, after dehulling, husks can be highly contaminated with OTA, as also indicated by its enhanced concentration in soluble coffees adulterated with husks and parchment. A minimum water activity of 0.80 (about 14% MC) is required for in vitro OTA production on green coffee, a fact that does not rule out the possibility of OTA contamination due to improper transportation and storage of green coffee. However, this appears not to be a major route for OTA contamination of coffee. OTA contamination can clearly be minimized by following good agricultural practice and a subsequent post-harvest handling consisting of appropriate techniques for drying, grading, transportation and storage of green coffee; these procedures are well established.

Coffee↗

A reproduction/teratology study of brewed and instant decaffeinated coffees.

Sprague-Dawley rats of both sexes were given, in place of their drinking water, full-strength or 50 or 25% dilutions of either brewed or instant decaffeinated coffees for about 6 mo from weaning. These levels are equivalent to the human consumption of about 50, 25, or 12 cups of coffee per day. Controls were given either distilled water, or full-strength or a 25% solution of regular brewed coffee. The rats were bred twice after 91 d to assess reproduction and teratogenicity. The parent animals given decaffeinated coffees and 100% regular coffee drank less than the rats given water, while the rats given 25% regular coffee drank more. No effects on body weight gain or feed efficiency were seen, except that the group given 100% regular coffee gained significantly less weight than the water controls. None of the coffee treatments had a significant effect on reproductive characteristics such as conception rate, number born, or number weaned. During the second pregnancy, no significant effects from the coffee treatments were seen on early embryotoxicity measured in dams sacrificed on d 13 of pregnancy or fetal toxicity in dams sacrificed on d 21. No significant fetal abnormalities due to any of the coffee treatments were observed in either soft-tissue or skeletal examinations, although there was a significant increase in unossified sternebrae in the fetuses from dams given the full-strength regular coffee.

Abnormalities, Drug-Induced↗

Coffee consumption and plasma total homocysteine: The Hordaland Homocysteine Study.

The health consequences of coffee drinking remain controversial. We report on an association between coffee consumption and the concentration of total homocysteine (tHcy) in plasma, a risk factor for cardiovascular disease and for adverse pregnancy outcome. The study population consisted of 7589 men and 8585 women 40-67 y of age and with no history of hypertension, diabetes, ischemic heart disease, or cerebrovascular disease. They were recruited from Hordaland county of western Norway in 1992-1993. Daily use of coffee was reported by 89.1% of the participants, of whom 94.9% used caffeinated filtered coffee. There was a marked positive dose-response relation between coffee consumption and plasma tHcy, which was stronger than the relation between coffee and total serum cholesterol. In 40-42-y-old men, mean tHcy was 10.1 mumol/L for nonusers and 12.0 mumol/L for drinkers of > or = 9 cups of coffee/d. Corresponding tHcy concentrations in 40-42-y-old women were 8.2 and 10.5 mumol/L, respectively. Although coffee drinking was associated with smoking and lower intake of vitamin supplements and fruit and vegetables, the coffee-tHcy association was only moderately reduced after these variables were adjusted for. The combination of cigarette smoking and high coffee intake was associated with particularly high tHcy concentrations. A strong inverse relation between tea and tHcy concentration in univariate analysis was substantially attenuated after smoking and coffee drinking were adjusted for. The results of the present report should promote future studies on tHcy as a possible mediator of adverse clinical effects related to heavy coffee consumption.

Adult↗

The acute effects of coffee and caffeine on human interdigestive exocrine pancreatic secretion.

The effects of coffee on exocrine pancreatic secretion are unknown but may be important, because a link between chronic stimulation of pancreatic secretion and experimental chemical carcinogenesis and an association between coffee drinking and human pancreatic adenocarcinoma have been reported. We measured exocrine pancreatic trypsin and gastric acid secretions collected through orogastroduodenal tubes and serum gastrin in eight non-coffee drinkers and eight coffee drinkers. During fasting, after one interdigestive cycle control period, one of four 250-ml samples [plain water, water plus caffeine (4.6 mg/kg), decaffeinated coffee (127.9 mg/kg), caffeinated coffee (127.9 mg/kg)] was administered through the orogastric tube. Caffeinated and decaffeinated coffee (p = 0.008), caffeine (p = 0.03), and an unidentified substance(s) in coffee other than caffeine (p = 0.008) were associated with increased interdigestive exocrine pancreatic trypsin secretion. In addition, we also confirmed that coffee and caffeine stimulated gastric acid secretion (p = 0.02) and decaffeinated coffee raised serum gastrin concentrations (p = 0.005). If an association between coffee and pancreatic carcinogenesis exists, chronic stimulation of the exocrine pancreas by secretagogues could result in a gland susceptible to carcinogenesis.

Adenocarcinoma↗

Coffee, caffeine, and coronary heart disease.

PURPOSE OF REVIEW: This review summarizes and highlights recent advances in current knowledge of the relationship between coffee and caffeine consumption and risk of coronary heart disease. Potential mechanisms and genetic modifiers of this relationship are also discussed. RECENT FINDINGS: Studies examining the association between coffee consumption and coronary heart disease have been inconclusive. Coffee is a complex mixture of compounds that may have either beneficial or harmful effects on the cardiovascular system. Randomized controlled trials have confirmed the cholesterol-raising effect of diterpenes present in boiled coffee, which may contribute to the risk of coronary heart disease associated with unfiltered coffee consumption. A recent study examining the relationship between coffee and risk of myocardial infarction incorporated a genetic polymorphism associated with a slower rate of caffeine metabolism and provides strong evidence that caffeine also affects risk of coronary heart disease. Several studies have reported a protective effect of moderate coffee consumption, which suggests that coffee contains other compounds that may be beneficial. SUMMARY: Diterpenes present in unfiltered coffee and caffeine each appear to increase risk of coronary heart disease. A lower risk of coronary heart disease among moderate coffee drinkers might be due to antioxidants found in coffee.

Beverages↗

The genetics of tea and coffee drinking and preference for source of caffeine in a large community sample of Australian twins.

AIMS: To investigate the genetic and environmental influences on tea consumption and their commonalities with coffee consumption; and to further examine the genetic and environmental aetiology of preference for tea/coffee. DESIGN: A classical twin design was used in which the similarity of identical and non-identical twins is compared, enabling estimates of genetic, common environmental and unique environmental influence on the trait. SETTING AND PARTICIPANTS: An Australian population-based sample of 1796 identical (i.e. monozygotic) and 2013 non-identical (i.e. dizygotic) twin pairs aged 16-87 years was studied, roughly three-fifths of whom were female. The sample represented approximately 70% of those approached for study participation. MEASUREMENTS: As part of a Health and Lifestyle Questionnaire, respondents were asked how many cups of each tea and coffee they consumed per day. Additional measures of 'total tea and coffee consumption' and 'preference for coffee' were calculated. FINDINGS: Age was positively associated with tea consumption but negatively associated with coffee preference; women consumed more beverages than men, but showed a lower preference for coffee. An inverse relation between tea and coffee consumption--larger in females (-0.41) than males (-0.34)--was supported. This association was mediated entirely by the unique environment in males, and by both the unique environment (68.3%) and genes (31.7%) in females. Tea and coffee drinking were shown to have similar heritabilities (0.46) in males, but tea consumption was influenced by common environmental factors whereas coffee consumption was not. Coffee preference was shown to be influenced by genes (0.42) and the unique environment (0.58). CONCLUSIONS: As the patterns of genetic and environmental variation were shown to differ for tea and coffee consumption it may be more informative to retain them as separate measures of caffeine intake in future studies of stimulant use and taste perception.

Adolescent↗

Extraction and analysis of coffee bean allergens.

Workers in the coffee industry can develop occupational allergic disease upon exposure to dust associated with coffee manufacturing. Since controversy exists as to the source or chemical nature of these allergens, the mouse model of reaginic antibody production was used to assess the potential sources of allergens in samples obtained from a local coffee manufacturing plant. Mice were immunized with extracts of coffee dust and beans and the resulting reaginic antibody response determined by the passive cutaneous anaphylaxis reaction. Cross-reacting allergens were detected in samples of coffee dust, cleaner can debris and green coffee beans, but not in chaff or roasted coffee beans. None of the allergens detected in coffee samples cross-reacted with extract of castor beans, although these extracts contained the potent castor bean allergen. Green coffee bean allergens partially purified by gel filtration were heterogeneous with respect to molecular size, although quite similar in their reactivity with reaginic antiserum. These results suggest that the green coffee bean is the major source of allergen in coffee manufacturing plants. This allergen is heterogeneous with respect to size and heat lability, and is immunochemically different from the castor bean allergen.

Allergens↗

Comparison of effect of cafetière and filtered coffee on serum concentrations of liver aminotransferases and lipids: six month randomised controlled trial.

OBJECTIVE: To study the effects of prolonged intake of cafetière coffee, which is rich in the diterpenes cafestol and kahweol, on serum aminotransferase and lipid concentrations. DESIGN: Randomised parallel controlled trial. SUBJECTS: 46 healthy men and women aged 19 to 69. INTERVENTION: Consumption of five to six strong cups (0.9 litres) a day of either cafetière (22 subjects) or filtered coffee (24 subjects) for 24 weeks. MAIN OUTCOME MEASURES: Mean changes in serum aminotransferase and lipid concentrations. RESULTS: Cafetière coffee raised alanine aminotransferase concentration by up to 80% above baseline values relative to filtered coffee. After 24 weeks the rise was still 45% (9 U/l (95% confidence interval 3 to 15 U/l), P = 0.007). Alanine aminotransferase concentration exceeded the upper limit of normal in eight of the 22 subjects drinking cafetière coffee, being twice the upper limit of normal in three of them. Cafetière coffee raised low density lipoprotein cholesterol concentrations by 9-14%. After 24 weeks the rise was 0.26 mmol/l (0.04 to 0.47 mmol/l) (P = 0.03) relative to filtered coffee. Triglyceride concentrations initially rose by 26% with cafetière coffee but returned close to baseline values within six months. All increases were reversible after the intervention was stopped. CONCLUSIONS: Daily consumption of five to six cups of strong cafetière coffee affects the integrity of liver cells as suggested by small increases in serum alanine aminotransferase concentration. The effect does not subside with prolonged intake. High intakes of coffee brews rich in cafestol and kahweol may thus be responsible for unexplained increases in this enzyme activity in apparently healthy subjects. Cafetière coffee also raises low density lipoprotein cholesterol concentration and thus the risk of coronary heart disease.

Adult↗

The effects of coffee and napping on nighttime highway driving: a randomized trial.

BACKGROUND: Sleep-related accidents often involve healthy young persons who are driving at night. Coffee and napping restore alertness, but no study has compared their effects on real nighttime driving performances. OBJECTIVE: To test the effects of 125 mL of coffee (half a cup) containing 200 mg of caffeine, placebo (decaffeinated coffee containing 15 mg of caffeine), or a 30-minute nap (at 1:00 a.m.) in a car on nighttime driving performance. DESIGN: Double-blind, randomized, crossover study. SETTING: Sleep laboratory and open highway. PARTICIPANTS: 12 young men (mean age, 21.3 years [SD, 1.8]). MEASUREMENTS: Self-rated fatigue and sleepiness, inappropriate line crossings from video recordings during highway driving, and polysomnographic recordings during the nap and subsequent sleep. INTERVENTION: Participants drove 200 km (125 miles) between 6:00 p.m. and 7:30 p.m. (daytime reference condition) or between 2:00 a.m. and 3:30 a.m. (coffee, decaffeinated coffee, or nap condition). After intervention, participants returned to the laboratory to sleep. RESULTS: Nighttime driving performance was similar to daytime performance (0 to 1 line crossing) for 75% of participants after coffee (0 or 1 line crossing), for 66% after the nap (P = 0.66 vs. coffee), and for only 13% after placebo (P = 0.041 vs. nap; P = 0.014 vs. coffee). The incidence rate ratios for having a line crossing after placebo were 3.7 (95% CI, 1.2 to 11.0; P = 0.001) compared with coffee and 2.9 (CI, 1.7 to 5.1; P = 0.021) compared with nap. A statistically significant interindividual variability was observed in response to sleep deprivation and countermeasures. Sleep latencies and efficiency during sleep after nighttime driving were similar in the 3 conditions. LIMITATIONS: Only 1 dose of coffee and 1 nap duration were tested. Effects may differ in other patient or age groups. CONCLUSIONS: Drinking coffee or napping at night statistically significantly reduces driving impairment without altering subsequent sleep.

Adult↗

Woody plant diversity and structure of shade-grown-coffee plantations in northern Chiapas, Mexico.

Shade-grown coffee is an agricultural system that contains some forest-like characteristics. However, structure and diversity are poorly known in shade coffee systems. In 61 coffee-growers' plots of Chiapas, Mexico, structural variables of shade vegetation and coffee yields were measured, recording species and their use. Coffee stands had five vegetation strata. Seventy seven woody species mostly used as wood were found (mean density 371.4 trees per hectare). Ninety percent were native species (40% of the local flora), the remaining were introduced species, mainly fruit trees/shrubs. Diametric distribution resembles that of a secondary forest. Principal Coordinates Analysis grouped plots in four classes by the presence of Inga, however the majority of plots are diverse. There was no difference in equitability among groups or coffee yields. Coffee yield was 835 g clean coffee per shrub, or ca. 1,668 kg ha-1. There is a significant role of shade-grown coffee as diversity refuge for woody plants and presumably associated fauna as well as an opportunity for shade-coffee growers to participate in the new biodiversity-friendly-coffee market.

Coffee↗

Inhibitory effect of coffee on lower esophageal sphincter pressure.

We examined the effect of 150 ml of caffeinated instant coffee at two pHs, 4.5 and 7.0, on lower esophageal sphincter pressure in 20 normal volunteers and 16 patients with reflux esophagitis. When ingested alone coffee at pH 4.5 and 7.0 caused a decrease in basal sphincter pressure in normal volunteers from 19.4 +/- 1.5 to 13.7 +/- 1.0 mmHg (P ¿ 0.01) and from 18.7 +/- 1.5 to 16.0 +/- 0.8 mmHg (P < 0.05) respectively. When coffee at pH 4.5 was drunk with a mixed nutrient test meal, the resting sphincter pressure in normal subjects fell after 30-60 min with the nadir, 11.2 +/- 1.0 mmHg, being recorded at 60 min (P < 0.01). Coffee at pH 7.0 with the test meal resulted in a fall in pressure to 14.3 +/- 1.5 mmHg (P < 0.02) at 60 min. In patients with reflux esophagitis, coffee at pH 4.5 lowered lower esophageal sphincter pressure from 9.1 +/- 1.0 to 5.5 +/- 0.6 mmHg (P < 0.005); coffee at pH 7.0 decreased lower esophageal sphincter pressure from 8.5 +/- 1.1 to 6.9 +/- 0.7 mmHg (P < 0.05). In these patients, mean basal pressure, 9.2 +/- 0.8 mmHg, decreased to 5.2 +/- 0.7 mmHg (P < 0.001) 45 min after drinking coffee at pH 4.5 with the test meal. Coffee at the neutral pH caused a fall in pressure from 8.8 +/- 1.1 to 6.5 +/- 0.7 mmHg at 60 min after the test meal. Thus, coffee at either pH 4.5 or 7.0 caused a decrease in fasting and postcibal lower esophageal sphincter pressure in normal volunteers and patients with reflux esophagitis. The magnitude and the duration of the effect were greater after coffee at the lower pH. These data support the clinical belief that coffee may cause or aggravate heartburn by decreasing lower esophageal sphincter pressure.

Adult↗

Assessment the Effects of Roasted and Non-Roasted Coffee Extracts on Colon Cancer Cells.

Coffee extracts contain numerous bioactive compounds. Given the dietary link between coffee consumption and colorectal cancer, this study compared the effects of roasted and green (unroasted) coffee extracts on human colorectal cancer cells (HCT116) and non-cancerous fibroblasts (BJ-5ta) to evaluate how processing influences proliferation and molecular signaling. Real-time cell analysis (RTCA), qRT-PCR, and label-free quantitative proteomic analysis were performed to assess cellular responses. MTS and RTCA showed that in BJ-5Ta fibroblasts, coffee extracts increased proliferation in the order CNR < CAR < CAU < CNU, whereas the trend was reversed in HCT116 cancer cells. Proteomic analysis revealed that in BJ-5Ta cells, unroasted coffee extract caused downregulation of the ribosome pathway, and natural coffee extract caused downregulation of the gap junction pathway, indicating reduced protein synthesis and cell-cell communication as a potential stress-adaptive response. In contrast, in HCT116 cells, unroasted coffee extract upregulated the ribosome pathway. Also, natural coffee extract upregulated the pentose phosphate pathway in HCT116 cells, which may enhance NADPH production and reduce oxidative stress. Current evidence suggests coffee's bioactive compounds may have different effects varying by coffee extract type and their preparation.

Humans↗

Coffee consumption and risk of type 2 diabetes mellitus among middle-aged Finnish men and women.

CONTEXT: Only a few studies of coffee consumption and diabetes mellitus (DM) have been reported, even though coffee is the most consumed beverage in the world. OBJECTIVE: To determine the relationship between coffee consumption and the incidence of type 2 DM among Finnish individuals, who have the highest coffee consumption in the world. DESIGN, SETTING, AND PARTICIPANTS: A prospective study from combined surveys conducted in 1982, 1987, and 1992 of 6974 Finnish men and 7655 women aged 35 to 64 years without history of stroke, coronary heart disease, or DM at baseline, with 175 682 person-years of follow-up. Coffee consumption and other study parameters were determined at baseline using standardized measurements. MAIN OUTCOME MEASURES: Hazard ratios (HRs) for the incidence of type 2 DM were estimated for different levels of daily coffee consumption. RESULTS: During a mean follow-up of 12 years, there were 381 incident cases of type 2 DM. After adjustment for confounding factors (age, study year, body mass index, systolic blood pressure, education, occupational, commuting and leisure-time physical activity, alcohol and tea consumption, and smoking), the HRs of DM associated with the amount of coffee consumed daily (0-2, 3-4, 5-6, 7-9, > or =10 cups) were 1.00, 0.71 (95% confidence interval [CI], 0.48-1.05), 0.39 (95% CI, 0.25-0.60), 0.39 (95% CI, 0.20-0.74), and 0.21 (95% CI, 0.06-0.69) (P for trend<.001) in women, and 1.00, 0.73 (95% CI, 0.47-1.13), 0.70 (95% CI, 0.45-1.05), 0.67 (95% CI, 0.40-1.12), and 0.45 (95% CI, 0.25-0.81) (P for trend =.12) in men, respectively. In both sexes combined, the multivariate-adjusted inverse association was significant (P for trend <.001) and persisted when stratified by younger and older than 50 years; smokers and never smokers; healthy weight, overweight, and obese participants; alcohol drinker and nondrinker; and participants drinking filtered and nonfiltered coffee. CONCLUSION: Coffee drinking has a graded inverse association with the risk of type 2 DM; however, the reasons for this risk reduction associated with coffee remain unclear.

Adult↗

Coffee consumption not associated with risk of pancreas cancer in Finland.

BACKGROUND: Coffee consumption has been brought to focus as a possible risk factor for pancreas cancer. After having reviewed the available evidence, an International Agency for Research on Cancer working group concluded in 1991 that the evidence in humans that coffee drinking is carcinogenic in the pancreas is "inadequate," since the available data were considered suggestive of a weak relationship with high levels of coffee consumption, but the possibility that this was due to bias or confounding was judged tenable. METHODS: The association between coffee consumption and pancreas cancer risk was examined in a case-referent study in Finland. Data on coffee consumption 20 years prior to the diagnosis of cancer were obtained from the next of kin of 662 cases of pancreas cancer and 1,770 referent (stomach, colon, and rectum) cancers. The results were expressed as crude and age-, gender-, and tobacco smoking-adjusted odds ratios and 95% confidence intervals for three daily coffee dose categories 20 years prior to cancer diagnosis. RESULTS: The data failed to demonstrate any association between coffee consumption and risk for pancreas cancer. The crude odds ratios varied between 0.7 (95% confidence interval 0.3-1.5) and 1.3 (0.7-2.6), the adjusted ones between 0.5 (0.2-1.2) and 1.1 (0.6-2.1) in the different daily dose categories of coffee and between contrasts with the three referent cancers. The highest odds ratios were associated with the contrast between pancreas and colon cancer, the lowest between pancreas and rectum cancer. Adjustment for gender, age, and tobacco smoking slightly decreased the values of the odds ratios. The power of the study was low, however, to detect possible weak increases associated with coffee consumption. CONCLUSIONS: The results are unlikely to be negatively biased, and are compatible with the majority of epidemiologic results advanced, suggesting no positive association between coffee consumption and the risk of pancreas cancer.

Case-Control Studies↗

Coffee consumption and blood pressure: a randomized, crossover clinical trial.

OBJECTIVE: To examine the effect of moderate coffee consumption on blood pressure over a prolonged period of time. Previous work in this area has used primarily purified caffeine. DESIGN: A prospective, randomized, crossover clinical trial. SETTING: A hypertension specialty outpatient clinic at the University of Tennessee, Memphis. PATIENTS: Healthy, young, white men who were moderate coffee drinkers (less than 6 cups/day) were recruited. Twenty-four subjects were randomized and 21 (average age 35.5 years) completed the trial. INTERVENTIONS: Subjects were randomized to one of two groups: Group A drank three or more cups of coffee/day for two months, then crossed over to abstaining from coffee for two months; group B abstained from coffee first, then crossed over to drinking coffee. Only filter-brewed coffee was used. Subjects were seen at monthly intervals for blood pressure measurements. MEASUREMENTS AND MAIN RESULTS: The average coffee consumption was 3.6 cups/day during the coffee-drinking phases. There was no difference between the coffee-drinking phase and the abstention phase in either systolic blood pressure (110.1 mmHg vs. 108.0 mmHg, respectively; 95% CI of difference -7.3, 2.5) or diastolic blood pressure (67.2 mmHg vs. 69.6 mmHg, respectively; 95% CI of difference -2.2, 6.4). CONCLUSIONS: Moderate daily consumption of coffee does not elevate blood pressure.

Adult↗

Coffee and coronary heart disease: a review.

Since the early 1900s, coffee has been implicated as having adverse effects on human health. Recent attention has focused on coffee's relation to CHD, but because of conflicting results of epidemiologic studies on coffee and CHD mortality, attention has turned to the effects of coffee and caffeine on individual CHD risk factors. Coffee's effect on serum lipids does not appear to be due to caffeine. If in fact an adverse effect on lipids exists, it may be related to other factors including biochemical constituents other than caffeine, hardness of the water used in preparation, and the method of preparation, filtered coffee having no effect. The data are fairly convincing that chronic coffee ingestion does not induce hypertension, although acute consumption produces a small, short-lived increase in BP. The least well understood effect of coffee is its potential to induce cardiac arrhythmias, including potentially lethal ventricular ectopy in certain individuals. More work is needed in this area of arrhythmias before any concrete recommendations can be made. Until more convincing evidence against coffee is compiled, it appears that, at least in moderate amounts in otherwise healthy persons, coffee is a safe beverage.

Animals↗

Potential genotoxic, mutagenic and antimutagenic effects of coffee: a review.

Coffee and caffeine are mutagenic to bacteria and fungi, and in high concentrations they are also mutagenic to mammalian cells in culture. However, the mutagenic effects of coffee disappear when bacteria or mammalian cells are cultured in the presence of liver extracts which contain detoxifying enzymes. In vivo, coffee and caffeine are devoid of mutagenic effects. Coffee and caffeine are able to interact with many other mutagens and their effects are synergistic with X-rays, ultraviolet light and some chemical agents. Caffeine seems to potentiate rather than to induce chromosomal aberrations and also to transform sublethal damage of mutagenic agents into lethal damage. Conversely, coffee and caffeine are also able to inhibit the mutagenic effects of numerous chemicals. These antimutagenic effects depend on the time of administration of coffee as compared to the acting time of the mutagenic agent. In that case, caffeine seems to be able to restore the normal cycle of mitosis and phosphorylation in irradiated cells. Finally, the potential genotoxic and mutagenic effects of the most important constituents of coffee are reviewed. Mutagenicity of caffeine is mainly attributed to chemically reactive components such as aliphatic dicarbonyls. The latter compounds, formed during the roasting process, are mutagenic to bacteria but less to mammalian cells. Hydrogen peroxide is not very active but seems to considerably enhance mutagenic properties of methylglyoxal. Phenolic compounds are not mutagenic but rather anticarcinogenic. Benzopyrene and mutagens formed during pyrolysis are not mutagenic whereas roasting of coffee beans at high temperature generates mutagenic heterocyclic amines. In conclusion, the mutagenic potential of coffee and caffeine has been demonstrated in lower organisms, but usually at doses several orders of magnitude greater than the estimated lethal dose for caffeine in humans. Therefore, the chances of coffee and caffeine consumption in moderate to normal amounts to induce mutagenic effects in humans are almost nonexistent.

Animals↗