Effects of caffeine on human health

Caffeine consumption and the risk of breast cancer in a large prospective cohort of women

BACKGROUND

Prospective data relating caffeine consumption to breast cancer risk are limited.

METHODS

We evaluated the association between caffeine consumption and breast cancer risk in women enrolled in a completed cancer prevention trial. Detailed dietary information was obtained at baseline (1992-1995) from 38 432 women 45 years or older and free of cancer. During a mean follow-up of 10 years, we identified 1188 invasive breast cancer cases.

RESULTS

Consumption of caffeine and caffeinated beverages and foods was not statistically significantly associated with overall risk of breast cancer. The multivariate relative risks (RRs) of breast cancer were 1.02 (95% confidence interval [CI], 0.84-1.22) for caffeine (top vs bottom quintile), 1.08 (0.89-1.30) for coffee (> or =4 cups daily vs almost never), and 1.03 (0.85-1.25) for tea (> or =2 cups daily vs almost never). However, in women with benign breast disease, a borderline significant positive association with breast cancer risk was observed for the highest quintile of caffeine consumption (RR, 1.32; 95% CI, 0.99-1.76) and for the highest category of coffee consumption (> or =4 cups daily) (1.35; 1.01-1.80); tests for interaction were marginally significant. Caffeine consumption was also significantly positively associated with risk of estrogen receptor-negative and progesterone receptor-negative breast cancer (RR, 1.68; 95% CI, 1.01-2.81) and breast tumors larger than 2 cm (1.79; 1.18-2.72).

CONCLUSIONS

These data show no overall association between caffeine consumption and breast cancer risk. The possibility of increased risk in women with benign breast disease or for tumors that are estrogen and progesterone receptor negative or larger than 2 cm warrants further study.

Review of the dietary reference intake for calcium: where do we go from here?

In this article the science relied on to establish the Dietary Reference Intakes (DRI) specifically for calcium was examined. The latest dietary recommendations for the essential nutrients significant with respect to their roles in bone metabolism and health were reported in the Dietary Reference Intakes for Calcium, Phosphorus, Magnesium, Vitamin D, and Fluoride (1997) (NIM, 1997). For calcium an adequate intake was recommended because insufficient data were available at the time to determine specific Recommended Dietary Allowances. Dietary intake data and the controversies regarding the role calcium may play in other chronic diseases have also been discussed. Advances and continued dilemmas regarding these topics reported since the publication of the DRI were also addressed in this review. A recent Dietary Reference Intake Research Synthesis Workshop report identified an extensive range of suggested future research directions needed to improve our understanding of calcium and bone and health.

Chemoprevention of dibenzo[a,l]pyrene transplacental carcinogenesis in mice born to mothers administered green tea: primary role of caffeine

Our laboratory recently developed a mouse model of transplacental induction of lymphoma, lung and liver cancer by the polycyclic aromatic hydrocarbon, dibenzo[a,l]pyrene (DBP). Pregnant B6129SF1 females, bred to 129S1/SvIm males, were treated on day 17 of gestation with an oral dose of 15 mg/kg DBP. Beginning on day 0 of gestation, dams were given (ad lib) buffered water, 0.5% green tea, 0.5% decaffeinated green tea, caffeine or epigallocatechin-3-gallate (EGCG) (both at equivalent concentrations found in tea). The concentration of the teas (and corresponding caffeine and EGCG) was increased to 1.0% upon entering the second trimester, 1.5% at onset of the third trimester and continued at 1.5% until pups were weaned at 21 days of age. Offspring were raised with normal drinking water and AIN93G diet. Beginning at 2 months of age, offspring experienced significant mortalities due to an aggressive T-cell lymphoma as seen in our previous studies. Ingestion of caffeinated, but not decaffeinated, green tea provided modest but significant protection (P = 0.03) against mortality. Caffeine provided a more robust (P = 0.006) protection, but EGCG was without effect. Offspring also developed DBP-dependent lung adenomas. All treatments significantly reduced lung tumor multiplicity relative to controls (P < 0.02). EGCG was most effective at decreasing tumor burden (P = 0.005) by on average over 40% compared with controls. Induction of Cytochrome P450 (Cyp)1b1 in maternal liver may reduce bioavailability of DBP to the fetus as a mechanism of chemoprevention. This is the first demonstration that maternal ingestion of green tea, during pregnancy and nursing, provides protection against transplacental carcinogenesis.

Protective effect of green tea polyphenols on bone loss in middle-aged female rats

Recent studies have suggested that green tea polyphenols (GTP) are promising agents for preventing bone loss in women. Findings that GTP supplementation resulted in increased urinary GTP concentrations and bone mass via an increase of antioxidant capacity and/or a decrease of oxidative stress damage suggest a significant role of GTP in bone health of women.

INTRODUCTION

Recent studies suggested that green tea polyphenols (GTP) are promising agents for preventing bone loss in women. However, the mechanism related to the possible protective role of GTP in bone loss is not well understood.

METHODS

This study evaluated bioavailability, mechanisms, bone mass, and safety of GTP in preventing bone loss in middle-aged rats without (sham, SH) and with ovariectomy (OVX). A 16-week study of 2 (SH vs. OVX) x 3 (no GTP, 0.1% GTP, and 0.5% GTP in drinking water) factorial design using 14-month-old female rats (n = 10/group) was performed. An additional 10 rats in baseline group were euthanized at the beginning of study to provide baseline parameters.

RESULTS

There was no difference in femur bone mineral density between baseline and the SH+0.5% GTP group. Ovariectomy resulted in lower values for liver glutathione peroxidase activity, serum estradiol, and bone mineral density. GTP supplementation resulted in increased urinary epigallocatechin and epicatechin concentrations, liver glutathione peroxidase activity and femur bone mineral density, decreased urinary 8-hydroxy-2'-deoxyguanosine and urinary calcium levels, but no effect on serum estradiol and blood chemistry levels.

CONCLUSION

We conclude that a bone-protective role of GTP may contribute to an increase of antioxidant capacity and/or a decrease of oxidative stress damage.

Comparing the benefits of caffeine, naps and placebo on verbal, motor and perceptual memory

Caffeine, the world's most common psychoactive substance, is used by approximately 90% of North Americans everyday. Little is known, however, about its benefits for memory. Napping has been shown to increase alertness and promote learning on some memory tasks. We directly compared caffeine (200mg) with napping (60-90min) and placebo on three distinct memory processes: declarative verbal memory, procedural motor skills, and perceptual learning. In the verbal task, recall and recognition for unassociated words were tested after a 7h retention period (with a between-session nap or drug intervention). A second, different, word list was administered post-intervention and memory was tested after a 20min retention period. The non-declarative tasks (finger tapping task (FTT) and texture discrimination task (TDT)) were trained before the intervention and then retested afterwards. Naps enhanced recall of words after a 7h and 20min retention interval relative to both caffeine and placebo. Caffeine significantly impaired motor learning compared to placebo and naps. Napping produced robust perceptual learning compared with placebo; however, naps and caffeine were not significantly different. These findings provide evidence of the limited benefits of caffeine for memory improvement compared with napping. We hypothesize that impairment from caffeine may be restricted to tasks that contain explicit information; whereas strictly implicit learning is less compromised.

Caffeinated coffee consumption impairs blood glucose homeostasis in response to high and low glycemic index meals in healthy men

BACKGROUND

The ingestion of caffeine (5 mg/kg body weight) and a 75-g oral glucose load has been shown to elicit an acute insulin-insensitive environment in healthy and obese individuals and in those with type 2 diabetes.

OBJECTIVE

In this study we investigated whether a similar impairment in blood glucose management exists when coffee and foods typical of a Western diet were used in a similar protocol.

DESIGN

Ten healthy men underwent 4 trials in a randomized order. They ingested caffeinated (5 mg/kg) coffee (CC) or the same volume of decaffeinated coffee (DC) followed 1 h later by either a high or low glycemic index (GI) cereal (providing 75 g of carbohydrate) mixed meal tolerance test.

RESULTS

CC with the high GI meal resulted in 147%, 29%, and 40% greater areas under the curve for glucose (P < 0.001), insulin (NS), and C-peptide (P < 0.001), respectively, compared with the values for DC. Similarly, with the low GI treatment, CC elicited 216%, 44%, and 36% greater areas under the curve for glucose (P < 0.001), insulin (P < 0.01), and C-peptide (P < 0.01), respectively. Insulin sensitivity was significantly reduced (40%) with the high GI treatment after CC was ingested compared with DC; with the low GI treatment, CC ingestion resulted in a 29% decrease in insulin sensitivity, although this difference was not significant.

CONCLUSION

The ingestion of CC with either a high or low GI meal significantly impairs acute blood glucose management and insulin sensitivity compared with ingestion of DC. Future investigations are warranted to determine whether CC is a risk factor for insulin resistance.

Tea or coffee? A case study on evidence for dietary advice

The present paper explores the level of evidence required to justify giving dietary advice to the public. There are important practical differences between the development of public health nutrition guidelines and guidelines for clinical practice. While the gold standard for evidence for clinical practice guidelines is a meta-analysis of a number of randomised controlled trials, this is often unrealistic and sometimes unethical for the evaluation of public health nutrition interventions. Hence, epidemiological studies make up the bulk of evidence for nutrition guidelines. Tea and coffee are an interesting case study in relation to this issue. They are two of the most commonly consumed beverages worldwide, yet there is little dietary advice on their use. The evidence for a relationship between coffee or tea consumption and several diseases is discussed. The available studies, predominantly epidemiological, together with animal and in vitro studies, indicate that coffee and tea are both safe beverages. However, tea is the healthier option because it has a possible role in the prevention of several cancers and CVD. While the evidence for such relationships is not strong, the public will continue to drink both tea and coffee, and will continue to ask nutritionists to make recommendations. It is therefore argued that advice should be given on the best available data, as waiting for complete data to become available could have severe consequences for public health.

Chemical composition of green tea (Camellia sinensis) infusions commercialized in Portugal

To evaluate the potential benefits and risks associated with tea consumption it is important to identify the constituents of this beverage. Levels of some minerals, caffeine and catechins in green tea samples commercialized in Portugal were evaluated. Potassium is the metal present in larger amount (92-151 mg/l). The content of sodium, calcium, fluoride, aluminium, manganese and iron were 35-69, 1.9-3.5, 0.80-2.0, 1.0-2.2, 0.52-1.9, 0.020-0.128 mg/l, respectively. Chromium and selenium were not detected. The resulting data showed considerable variability in catechins content. The levels of epigallocatechin gallate (EGCG) ranged from 117 to 442 mg/l, epicatechin 3-gallate (EGC) from 203 to 471 mg/l, epigallocatechin (ECG) from 16.9 to 150 mg/l, epicatechin (EC) from 25 to 81 mg/l and catechin (C) from 9.03 to 115 mg/l. Caffeine contents in the green tea infusions studied were between 141-338 mg/l. Green tea infusions provide significant amounts of catechins and could be an important source of some minerals.

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.

Shifts in patterns and consumption of beverages between 1965 and 2002

BACKGROUND

Beverage patterning may play a role in partially explaining the rising rates of obesity in the United States, yet little work on overall trends and patterns exits. Our objective was to examine trends and patterns of beverage consumption among U.S. adults.

METHODS

We used data from the nationally representative Nationwide Food Consumption Surveys (1965, 1977 to 1978) and the National Health and Nutrition Surveys (1988 to 1994, 1999 to 2002). To examine trends we determined percent consuming and per capita and per consumer caloric intake from all beverages. We used cluster analysis to determine year-specific beverage patterns in 1977 and 2002.

RESULTS

The percentage of calories from beverages significantly increased between 1965 (11.8%), 1977 (14.2%), 1988 (18.5%), and 2002 (21.0%); this represents an overall increase of 222 calories per person per day from beverages, resulting largely from increased intake of calorically sweetened beverages. Beverage patterns in 2002 were more complex than in 1977 and were dominated by a greater number of beverages, reflecting the increase in alcohol, soda, and diet beverages.

CONCLUSION

Calories from beverages increased substantially from 1965 to 2002, providing a considerable source of daily calories. Given the upward trends in calorically sweetened, nutrient-deficient beverages and the shifts in overall beverage patterns, addressing beverage intake is a salient issue for adults.

Long-term, moderate coffee consumption is associated with lower prevalence of diabetes mellitus among elderly non-tea drinkers from the Mediterranean Islands (MEDIS Study)

BACKGROUND

We evaluated the association between coffee drinking and the prevalence of type 2 diabetes mellitus in elderly people from the Mediterranean islands.

METHODS

During 2005-2007, 500 men and 437 women (aged 65 to 100 years) from the islands of Cyprus (n = 300), Mitilini (n = 142), Samothraki (n = 100), Cephalonia (n = 104), Corfu (n = 160) and Crete (n = 131) participated in the survey. Cardiovascular disease (CVD) risk factors (i.e. hypertension, diabetes, hypercholesterolemia and obesity), as well as behavioral, lifestyle and dietary characteristics were assessed using face-to-face interviews and standard procedures. Among various factors, fasting blood glucose was measured and prevalence of type 2 diabetes mellitus was estimated, according to the established American Diabetes Association (ADA) criteria, while all participants were asked about the frequency of any type of coffee consumption over the last year.

RESULTS

Coffee drinking was reported by 84% of the participants, the majority of whom drank boiled coffee. The participants reported that they had consumed coffee for at least 30 years of their life. Data analysis adjusted for various potential confounders, revealed that, compared to non-consumption, the multi-adjusted odds ratio for having diabetes was 0.47 (95%, CI 0.32 to 0.69) for 1-2 cups/day, while it was 1.05 (95%, CI 0.70 to 1.55) for >3 cups/day, after adjusting for various potential confounders. The association of coffee drinking with diabetes was significant only among non-tea drinkers. Increased coffee intake was not associated with diabetes prevalence.

CONCLUSION

The data presented suggest that moderate coffee drinking is associated with a lower likelihood of having diabetes, after adjusting for various potential confounders.

Maternal caffeine consumption and risk of cardiovascular malformations

BACKGROUND

The physiologic effects and common use of caffeine during pregnancy call for examination of maternal caffeine consumption and risk of birth defects. Epidemiologic studies have yielded mixed results, but such studies have grouped etiologically different defects and have not evaluated effect modification.

METHODS

The large sample size and precise case classification of the National Birth Defects Prevention Study allowed us to examine caffeine consumption and specific cardiovascular malformation (CVM) case groups. We studied consumption of caffeinated coffee, tea, soda, and chocolate to estimate total caffeine intake and separately examined exposure to each caffeinated beverage. Smoking, alcohol, vasoactive medications, folic acid supplement use, and infant gender were evaluated for effect modification. Maternal interview reports for 4,196 CVM case infants overall and 3,957 control infants were analyzed.

RESULTS

We did not identify any significant positive associations between maternal caffeine consumption and CVMs. For tetralogy of Fallot, nonsignificant elevations in risk were observed for moderate (but not high) caffeine intake overall and among nonsmokers (ORs of 1.3 to 1.5). Risk estimates for both smoking and consuming caffeine were less than the sum of the excess risks for each exposure. We observed an inverse trend between coffee intake and risk of atrial septal defect; however, this single significant pattern of association might have been a chance finding.

CONCLUSIONS

Our study found no evidence for an appreciable teratogenic effect of caffeine with regard to CVMs.

Strategies to improve sleep during extended search and rescue operations

OBJECTIVE

This study investigated strategies to improve sleeping conditions during search and rescue operations during disaster response.

METHODS

Forty members of the Montgomery County (Maryland) Urban Search and Rescue Team were surveyed for individual sleep habits and sleeping aids used during extended deployments. Team members were also asked to suggest methods to improve sleep on future deployments.

RESULTS

The average amount of sleep during field operations was 5.4 hours with a range of 4-8 hours. Eight percent surveyed would prefer another schedule besides the 12-hour work day, all of whom proposed three 8-hour shifts. Fifteen percent of participants were interested in a pharmacological sleeping aid. Fifty percent of search and rescue members interviewed would consider using nonpharmacological sleeping aids. Furthermore, 40% of participants stated they had successfully devised self-employed methods of sleep aids for previous deployments, such as ear plugs, massage, mental imagery, personal routines, music and headphones, reading, and blindfolds.

CONCLUSIONS

This study suggests that availability of both pharmacological and nonpharmacological sleeping aids to search and rescue workers via the team cache could impact the quantity of sleep. Further investigation into methods of optimizing sleep during field missions could theoretically show enhanced performance through various aspects of missions including mitigation of errors, improved productivity, and improved overall physiological and emotional well-being of search and rescue personnel.

The antimutagenic activity of the major flavonoids of rooibos (Aspalathus linearis): some dose-response effects on mutagen activation-flavonoid interactions

The antimutagenic properties of the most prevalent flavonoids in rooibos (Aspalathus linearis) were compared in the Salmonella typhimurium mutagenicity assay using tester strains TA98 and TA100 with, respectively, 2-acetamido-fluorene (2-AAF) and aflatoxin B(1) (AFB(1)) as mutagens in the presence of metabolic activation. The flavonoids included the dihydrochalcones aspalathin and nothofagin and their flavone analogues, orientin and isoorientin, and vitexin and isovitexin, respectively, as well as luteolin, chrysoeriol, (+)-catechin, quercetin, isoquercitrin, hyperoside and rutin. Flavonoid-mutagen interactions ranged from antimutagenic, comutagenic and promutagenic to mutagenic, while dose-response effects were mutagen-specific and ranged from typical to atypical including biphasic and threshold effects. Aspalathin and nothofagin and their structural flavonoid analogues displayed moderate antimutagenic properties while luteolin and to some extent, chrysoeriol, showed activities comparable to those of the green tea flavonoid (-) epigallocatechin gallate (EGCG). Apart from their mutagenic and promutagenic properties, quercetin and isoquercitrin exhibited concentration-dependent comutagenic and/or antimutagenic effects against 2-AAF- and AFB(1)-induced mutagenesis. Different structural parameters known to affect the antimutagenic properties of flavonoids include their hydrophilic or lipophilic nature due to the extent of hydroxylation and O-methylation, glycosylation on the A and B rings, the C4-keto group and the C2-C3 double bond. The C ring does not appear to be a prerequisite when comparing for the antimutagenic activity of the dihydrochalcones when compared of the dihydrochalcones with the structural flavone analogues.

Is coffee a functional food?

Definitions of functional food vary but are essentially based on foods' ability to enhance the quality of life, or physical and mental performance, of regular consumers. The worldwide use of coffee for social engagement, leisure, enhancement of work performance and well-being is widely recognised. Depending on the quantities consumed, it can affect the intake of some minerals (K, Mg, Mn, Cr), niacin and antioxidant substances. Epidemiological and experimental studies have shown positive effects of regular coffee-drinking on various aspects of health, such as psychoactive responses (alertness, mood change), neurological (infant hyperactivity, Alzheimer's and Parkinson's diseases) and metabolic disorders (diabetes, gallstones, liver cirrhosis), and gonad and liver function. Despite this, most reviews do not mention coffee as fulfilling the criteria for a functional food. Unlike other functional foods that act on a defined population with a special effect, the wide use of coffee-drinking impacts a broad demographic (from children to the elderly), with a wide spectrum of health benefits. The present paper discusses coffee-drinking and health benefits that support the concept of coffee as a functional food.

Dietary fiber in brewed coffee

Coffee beans are rich in nondigestible polysaccharides (dietary fiber), which may partially pass into brewed coffee; however, to the authors' knowledge, there is not enough literature on dietary fiber in brewed coffee. A specific method to determine dietary fiber in beverages (enzymatic treatment plus dialysis) was applied to the coffees brewed by the most common methods (espresso, filter, soluble); results showed that brewed coffee contained a significantly higher amount of soluble dietary fiber (0.47-0.75 g/100 mL of coffee) than other common beverages. Coffee dietary fiber contains a large amount of associated antioxidant phenolics (8.7-10.5 mg/100 mL of brewed coffee).

Effect of caffeine on the risk of coronary heart disease- A re-evaluation

The effect of caffeine intake on the risk of coronary heart disease was studied. Twenty-one rats used were randomly divided into three experimental groups, the first group served as the control while the second and third groups were administered caffeine orally at doses of 10mg/kg body weight and 20mg/kg body weight respectively for fourteen days. Caffeine, at 10mg/kg body weight, significantly increased (P<0.05) serum LDL- cholesterol concentration and coronary heart disease risk ratio while it significantly reduced (P<0.05) serum triacylglycerol concentration when compared with controls. At 20mg/kg body weight, caffeine significantly increased (P<0.05) coronary heart disease risk ratio while it significantly reduced (P<0.05) serum HDL-cholesterol concentration and serum triacylgycerol concentration when compared with controls. No dose response effect was observed possibly suggestive of a threshold effect. These results suggest that caffeine predisposes consumers of caffeine containing beverages to coronary heart disease.

Green tea and stroke prevention: Emerging evidence

BACKGROUND

Stroke is a leading cause of morbidity and mortality in many countries. Green tea is a simple and inexpensive beverage that is showing promise in the prevention of several diseases, including stroke. However, epidemiological studies examining the preventive effects of tea on stroke have generated inconsistent results.

OBJECTIVE

To review the emerging evidence for green tea in stroke prevention.

METHODS

Published articles were located by searching the PubMed, ProQuest, CINAHL and other databases, using the keywords 'tea' and 'stroke' with no restriction on publication date. Reference lists of identified articles were also searched for relevant publications.

RESULTS

Two published epidemiological studies on green tea reported positive findings. A large number of studies have also proposed biological mechanisms by which tea or tea components may reduce the stroke risk. Additional studies are required from a variety of populations, assessing duration and different types of tea consumption on subtypes of stroke to provide further evidence.

CONCLUSION

Green tea is a safe and cheap beverage. Its consumption should be encouraged because it could potentially serve as a practical method for stroke prevention.

Effect of reducing caffeine intake on birth weight and length of gestation: randomised controlled trial

OBJECTIVE

To estimate the effect of reducing caffeine intake during pregnancy on birth weight and length of gestation.

DESIGN

Randomised double blind controlled trial.

SETTING

Denmark.

PARTICIPANTS

1207 pregnant women drinking at least three cups of coffee a day, recruited before 20 weeks' gestation.

INTERVENTIONS

Caffeinated instant coffee (568 women) or decaffeinated instant coffee (629 women).

MAIN OUTCOME MEASURES

Birth weight and length of gestation.

RESULTS

Data on birth weight were obtained for 1150 liveborn singletons and on length of gestation for 1153 liveborn singletons. No significant differences were found for mean birth weight or mean length of gestation between women in the decaffeinated coffee group (whose mean caffeine intake was 182 mg lower than that of the other group) and women in the caffeinated coffee group. After adjustment for length of gestation, parity, prepregnancy body mass index, and smoking at entry to the study the mean birth weight of babies born to women in the decaffeinated group was 16 g (95% confidence interval -40 to 73) higher than those born to women in the caffeinated group. The adjusted difference (decaffeinated group-caffeinated group) of length of gestation was -1.31 days (-2.87 to 0.25).

CONCLUSION

A moderate reduction in caffeine intake in the second half of pregnancy has no effect on birth weight or length of gestation.

TRIAL REGISTRATION

Clinical Trials NCT00131690 [ClinicalTrials.gov].

An examination of consumer exposure to caffeine from retail coffee outlets

OBJECTIVE

To analyse the distribution of caffeine doses obtainable from espresso coffee sold by a sample of commercial coffee vendors located on the Gold Coast, Qld, Australia.

DESIGN

A cross section of "Espresso/short black" coffee samples were purchased and analysed for their caffeine content using micellar electrokinetic capillary chromatography (MEKC). Coffees were collected using systematic cluster sampling across five major retail centres.

RESULTS

Ninety-seven espresso samples were analysed. The mean (+/-SD) quantity of caffeine was 106+/-38 mg/serve with a concentration of 2473+/-1092 mg/l. There was considerable variation in caffeine content. The range per serve was 25-214 mg whilst the concentration range was 580-7000 mg/l. Twenty-four samples (24.7%) contained 120 mg of caffeine or higher and 12 samples (12.3%) exceeded 167 mg per serve.

CONCLUSIONS AND IMPLICATIONS

The number of heavily caffeinated samples differentiates these findings from frequently cited caffeine values and supports similar data recently collected throughout the United Kingdom. As a result, the accuracy of any previous intake modelling regarding caffeine use in the Australian population is in doubt. The present data suggests that the probability of consumer exposure to high caffeine doses is greater than previously anticipated. Greater sample numbers from a broader selection of venues is required to confirm the extent of caffeine content variance within retail ground coffees.

Survey of caffeine levels in retail beverages in Portugal

The caffeine content of 85 retail beverage samples purchased from local supermarkets between 1995 and 2004 was determined. The potential intake of caffeine through the consumption of these beverages (but excluding coffee) was estimated for students of the University of Coimbra, Portugal. The caffeine content of the beverages ranged from 47.5 to 282.5 mg l(-1) for teas, from 20.1 to 47.2 mg l(-1) for tea extracts samples, and from 80.7 to 168.7 mg l(-1) for cola soft drinks. Caffeine was not completely absent from caffeine-free colas, and energy drinks had a far greater caffeine content than regular drinks, ranging from 21 to 2175 mg l(-1). Soft drinks were consumed by 72% of the individuals, although 14% of the survey participants did not drink any of the different types of the beverages studied. Contrary to expectations for this age group, no consumptions of energy drinks was reported. Daily caffeine intake was estimated to range from 4.7 to 200 mg day(-1), but with only 5% reporting a daily intake around 200 mg caffeine. Cola-type beverages were an important dietary source of caffeine for the population studied. Statistical differences in the caffeine intake between the male and female populations were found, with p = 0.014, being higher for the male population. Of the beverages studied, cola-type drinks showed statistical differences for the male population, p = 0.03, and tea showed statistical differences for female population p = 0.013, respectively.

Oral clefts and life style factors — A case-cohort study based on prospective Danish data

This study examines the association between oral clefts and first trimester maternal lifestyle factors based on prospective data from the Danish National Birth Cohort. The cohort includes approximately 100,000 pregnancies. In total 192 mothers gave birth to child with an oral cleft during 1997-2003. Information on risk factors such as smoking, alcohol consumption, tea, coffee, cola, and food supplements was obtained during pregnancy for these and 828 randomly selected controls. We found that first trimester maternal smoking was associated with an increased risk of oral clefts (odds ratio (OR): 1.50; 95% confidence interval (CIs): 1.05, 2.14). Although not statistically significant, we also saw associations with first trimester consumption of alcohol (OR: 1.11; CIs: 0.79, 1.55), tea (OR: 1.31; CIs: 0.93, 1.86), and drinking more than 1 l of cola per week (OR: 1.40; CIs: 0.92, 2.12). Furthermore supplementation with > or =400 mcg folic acid daily during the entire first trimester (OR: 0.75; CIs: 0.46, 1.22) suggested an inverse associated with oral clefts, similar to our results on coffee drinking. No effects were found for smaller doses of folic acid, vitamin A, B6 or B12 in this study. The present study found an association between oral clefts and smoking and, although not conclusive, supports an association of oral cleft with alcohol.

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.

Catechol-o-methyltransferase gene polymorphism modifies the effect of coffee intake on incidence of acute coronary events

Background

The role of coffee intake as a risk factor for coronary heart disease (CHD) has been debated for decades. We examined whether the relationship between coffee intake and incidence of CHD events is dependent on the metabolism of circulating catecholamines, as determined by functional polymorphism of the catechol-O-methyltransferase (COMT) gene.

Methodology/Principal Findings

In a cohort of 773 men who were 42 to 60 years old and free of symptomatic CHD at baseline in 1984–89, 78 participants experienced an acute coronary event during an average follow-up of 13 years. In logistic regression adjusting for age, smoking, family history of CHD, vitamin C deficiency, blood pressure, plasma cholesterol concentration, and diabetes, the odds ratio (90% confidence interval) comparing heavy coffee drinkers with the low activity COMT genotype with those with the high activity or heterozygotic genotypes was 3.2 (1.2–8.4). Urinary adrenaline excretion increased with increasing coffee intake, being over two-fold in heavy drinkers compared with nondrinkers (p = 0.008 for trend).

Conclusions/Significance

Heavy coffee consumption increases the incidence of acute coronary events in men with low but not high COMT activity. Further studies are required to determine to which extent circulating catecholamines mediate the relationship between coffee intake and CHD.

Neonatal caffeine administration causes a permanent increase in the dendritic length of prefrontal cortical neurons of rats

We studied the morphological changes of the dendritic length of the pyramidal neurons of the prefrontal cortex (PFC) induced by the effect of chronic administration of caffeine in the neonatal rat. The caffeine (50 mg/kg, s.c.) was injected from day 1 after birth (P1) to day 12 (P12). The morphology of the pyramidal neurons of layer 3 of the PFC was investigated in these animals at two different ages, before puberty (P35) and after puberty (P70). Before the animals were sacrificed by using overdoses of sodium pentobarbital and being perfused intracardially with 0.9% saline, the locomotor activity in a novel environment was measured. The brains were then removed, processed by the Golgi-Cox stain, and analyzed by the Sholl method. The dendritic morphology clearly showed that the neonatal animals administered caffeine showed an increase in the dendritic length of the pyramidal neurons of the PFC when compared with the control animals at both ages. The present results suggest that neonatal administration of caffeine may in part affect the dendritic morphology of the pyramidal cells of this limbic structure and this effect persists after puberty and may be implicated in several brain processes.

Coffee and health: a review of recent human research

Coffee is a complex mixture of chemicals that provides significant amounts of chlorogenic acid and caffeine. Unfiltered coffee is a significant source of cafestol and kahweol, which are diterpenes that have been implicated in the cholesterol-raising effects of coffee. The results of epidemiological research suggest that coffee consumption may help prevent several chronic diseases, including type 2 diabetes mellitus, Parkinson's disease and liver disease (cirrhosis and hepatocellular carcinoma). Most prospective cohort studies have not found coffee consumption to be associated with significantly increased cardiovascular disease risk. However, coffee consumption is associated with increases in several cardiovascular disease risk factors, including blood pressure and plasma homocysteine. At present, there is little evidence that coffee consumption increases the risk of cancer. For adults consuming moderate amounts of coffee (3-4 cups/d providing 300-400 mg/d of caffeine), there is little evidence of health risks and some evidence of health benefits. However, some groups, including people with hypertension, children, adolescents, and the elderly, may be more vulnerable to the adverse effects of caffeine. In addition, currently available evidence suggests that it may be prudent for pregnant women to limit coffee consumption to 3 cups/d providing no more than 300 mg/d of caffeine to exclude any increased probability of spontaneous abortion or impaired fetal growth.

Beverage caffeine intakes in young children in Canada and the US

PURPOSE

Throughout childhood there is a shift from predominantly milk-based beverage consumption to other types of beverages, including those containing caffeine. Although a variety of health effects in children and adults have been attributed to caffeine, few data exist on caffeine intake in children aged one to five years.

METHODS

Because beverages provide about 80% of total caffeine consumed in children of this age group, beverage consumption patterns and caffeine intakes were evaluated from two beverage marketing surveys: the 2001 Canadian Facts study and the 1999 United States Share of Intake Panel study.

RESULTS

Considerably fewer Canadian children than American children consume caffeinated beverages (36% versus 56%); Canadian children consume approximately half the amount of caffeine (7 versus 14 mg/day in American children). Differences were largely because of higher intakes of carbonated soft drinks in the US.

CONCLUSIONS

Caffeine intakes from caffeinated beverages remain well within safe levels for consumption by young children.

Black tea--helpful or harmful? A review of the evidence

OBJECTIVE

To consider whether consumption of black tea has a positive or negative impact on health.

DESIGN

Databases were searched for relevant epidemiological and clinical studies published between 1990 and 2004.

RESULTS

Clear evidence was found for coronary heart disease (CHD), where an intake of > or = 3 cups per day related to risk reduction. The mechanism could involve the antioxidant action of tea polyphenols. While experimental models have suggested that flavonoids attenuated cancer risk, epidemiological studies failed to demonstrate a clear effect for tea, although there is moderate evidence for a slightly positive or no effect of black tea consumption on colorectal cancer. Studies on cancer were limited by sample sizes and insufficient control of confounders. There is moderate evidence suggestive of a positive effect of black tea consumption on bone mineral density although studies were few. There is little evidence to support the effect of tea on dental plaque inhibition but evidence to support the contribution of tea to fluoride intakes and thus theoretical protection against caries. There was no credible evidence that black tea (in amounts typically consumed) was harmful. Normal hydration was consistent with tea consumption when the caffeine content was < 250 mg per cup. A moderate caffeine intake from tea appeared to improve mental performance, although sample sizes were small. There was no evidence that iron status could be harmed by tea drinking unless populations were already at risk from anaemia.

CONCLUSIONS

There was sufficient evidence to show risk reduction for CHD at intakes of > or = 3 cups per day and for improved antioxidant status at intakes of one to six cups per day. A maximum intake of eight cups per day would minimise any risk relating to excess caffeine consumption. Black tea generally had a positive effect on health.

Modifiable risk factors for impaired fertility in women: What nurse practitioners need to know

PURPOSE

To provide an overview of impaired fertility in childbearing-aged women, to review the current research on modifiable lifestyle risk factors implicated in its development, and to suggest strategies for nurse practitioners (NPs) to assist women in behavioral changes that will allow them to protect their fertility.

DATA SOURCES

Original research articles and comprehensive review articles identified through Medline, CINAHL, and OVID databases.

CONCLUSIONS

Research has shown that advancing age, a history of a sexually transmitted infection and/or pelvic inflammatory disease, extremes of body weight, and tobacco and caffeine use are potentially modifiable risk factors in the development of impaired fertility.

IMPLICATIONS FOR PRACTICE

NPs must be aware of the link between these behaviors and the development of impaired fertility in order to assist women in preserving their fertility. Individual counseling, education, and community-wide education strategies are discussed.

Consumption of coffee is associated with reduced risk of death attributed to inflammatory and cardiovascular diseases in the Iowa Women's Health Study

BACKGROUND

Coffee is the major source of dietary antioxidants. The association between coffee consumption and risk of death from diseases associated with inflammatory or oxidative stress has not been studied.

OBJECTIVE

We studied the relation of coffee drinking with total mortality and mortality attributed to cardiovascular disease, cancer, and other diseases with a major inflammatory component.

DESIGN

A total of 41,836 postmenopausal women aged 55-69 y at baseline were followed for 15 y. After exclusions for cardiovascular disease, cancer, diabetes, colitis, and liver cirrhosis at baseline, 27,312 participants remained, resulting in 410,235 person-years of follow-up and 4265 deaths. The major outcome measure was disease-specific mortality.

RESULTS

In the fully adjusted model, similar to the relation of coffee intake to total mortality, the hazard ratio of death attributed to cardiovascular disease was 0.76 (95% CI: 0.64, 0.91) for consumption of 1-3 cups/d, 0.81 (95% CI: 0.66, 0.99) for 4-5 cups/d, and 0.87 (95% CI: 0.69, 1.09) for > or =6 cups/d. The hazard ratio for death from other inflammatory diseases was 0.72 (95% CI: 0.55, 0.93) for consumption of 1-3 cups/d, 0.67 (95% CI: 0.50, 0.90) for 4-5 cups/d, and 0.68 (95% CI: 0.49, 0.94) for > or =6 cups/d.

CONCLUSIONS

Consumption of coffee, a major source of dietary antioxidants, may inhibit inflammation and thereby reduce the risk of cardiovascular and other inflammatory diseases in postmenopausal women.

Maternal Exposure to Caffeine and Risk of Congenital Anomalies

BACKGROUND

Caffeine is teratogenic in animal studies when administered at high concentrations. Previous review articles have concluded that maternal caffeine consumption does not influence the risk of congenital anomalies. These reviews were narrative rather than systematic. The objective of the current systematic review is to provide a critical appraisal of epidemiologic evidence.

METHODS

A search of the MEDLINE/PUBMED database (1966-October 2004) was conducted for all published epidemiologic studies with maternal intake of caffeine as an exposure and major malformations as an outcome. Study characteristics were abstracted, internal validity evaluated, and study findings summarized.

RESULTS

Twenty-five papers met the initial criteria for inclusion, of which 18 were subsequently excluded as a result of other limitations. Effect estimates for the remaining 7 studies were generally close to null. Specific subgroup analyses were summarized across studies (associations between coffee and cardiovascular malformations, coffee and oral clefts, and tea and cardiovascular malformations). Summary point estimates ranged from 1.0 to 1.2; the upper limits of all confidence intervals were less than 1.7.

CONCLUSIONS

There is no evidence to support a teratogenic effect of caffeine in humans. Current epidemiologic evidence is not adequate to assess the possibility of a small change in risk of congenital anomalies resulting from maternal caffeine consumption.

Chronic intake of caffeine during gestation down regulates metabotropic glutamate receptors in maternal and fetal rat heart

Caffeine is the most widely consumed substance in the world which antagonizes adenosine effects. Adenosine acting through A(1) receptors inhibits glutamate release which binds to metabotropic glutamate receptors (mGluRs). Recently, we have shown that maternal caffeine intake during gestation causes down-regulation of A(1) and metabotropic glutamate receptors in the brain of both rat mothers and fetuses. In the present work we provide evidence that caffeine also affects receptors in hearts, causing a decrease in mGluRs from both maternal and fetal hearts. A decrease in G(q/11) and PLC beta(1) proteins level was also observed in both tissues. However, phospholipase C activity was only affected in fetal heart, being significantly decreased. These results suggest an in vivo cross-talk mechanism between adenosine and glutamate receptors in peripheral tissues. Therefore, special attention should be paid to caffeine ingestion during gestation.

Maternal caffeine consumption and fetal death: a case-control study in Uruguay

The objective of this study was to examine the association between caffeine intake during pregnancy and fetal mortality in Montevideo, the capital city of Uruguay, taking into account several potential confounding factors. A population-based case-control study was conducted between 1 August 2002 and 31 December 2003. A total of 382 cases and 792 controls were recruited. Cases consisted of women hospitalised with a medically confirmed diagnosis of spontaneous antepartum fetal death, in all maternity hospitals during the study period. Antepartum fetal death was defined as a fetal death in which the attending doctor certified that the death occurred prior to the onset of labour. Fetal deaths were included if they were of at least 20 weeks' gestational age or weighed >350 g. Controls were women who had a live, vigorous and term adequate-for-gestational-age newborn. Multiple gestations and fetuses/newborns with evident congenital malformations were excluded. Only a small proportion of the mothers (8.1% of the cases and 9.5% of the controls) did not consume caffeine during pregnancy. Among consumers, mate drinking was the most frequent source of caffeine in both cases and controls. After controlling for mother's and her partner's education, history of abortions and/or fetal deaths, vomiting/nausea during the first trimester of gestation and attendance for prenatal care, the category of mean caffeine intake of > or = 300 mg/day showed a significantly increased risk of fetal death (OR 2.33 [1.23; 4.41]) compared with no caffeine consumption during pregnancy. The study also found that less-educated women, mothers who did not attend for prenatal care and women with a history of abortions and fetal death were at an increased risk of fetal death. As mate drinking is highly consumed among pregnant women in Uruguay, the association found with fetal death makes it a preventable risk factor.

A new proposed guidance system for beverage consumption in the United States

The Beverage Guidance Panel was assembled to provide guidance on the relative health and nutritional benefits and risks of various beverage categories. The beverage panel was initiated by the first author. The Panel's purpose is to attempt to systematically review the literature on beverages and health and provide guidance to the consumer. An additional purpose of the Panel is to develop a deeper dialog among the scientific community on overall beverage consumption patterns in the United States and on the great potential to change this pattern as a way to improve health. Over the past several decades, levels of overweight and obesity have increased across all population groups in the United States. Concurrently, an increased daily intake of 150-300 kcal (for different age-sex groups) has occurred, with approximately 50% of the increased calories coming from the consumption of calorically sweetened beverages. The panel ranked beverages from the lowest to the highest value based on caloric and nutrient contents and related health benefits and risks. Drinking water was ranked as the preferred beverage to fulfill daily water needs and was followed in decreasing value by tea and coffee, low-fat (1.5% or 1%) and skim (nonfat) milk and soy beverages, noncalorically sweetened beverages, beverages with some nutritional benefits (fruit and vegetable juices, whole milk, alcohol, and sports drinks), and calorically sweetened, nutrient-poor beverages. The Panel recommends that the consumption of beverages with no or few calories should take precedence over the consumption of beverages with more calories.

Effects of caffeine on olfactory and visual learning in the honey bee (Apis mellifera)

Although caffeine is known to improve alertness and arousal in humans and other mammals, its impacts on specific behaviours, including complex cognitive processes, remain controversial. We reasoned that the availability of an easily manipulable, but behaviourally complex invertebrate organism with a simpler nervous system would be beneficial to this field of research. We used a popular behavioural model, the honeybee, to evaluate the effects of caffeine on (1) the development of olfactory learning and (2) the performance in complex learning paradigms, including a 'delayed-match-to-sample' task and visual associative learning. To evaluate the efficacy of caffeine treatment, a variety of doses (0.4-400 ng/1 mg of body mass) were applied topically to tethered individuals. Behavioural testing was performed with either tethered or free-flying adult honeybees. We show that caffeine has marked cognitive effects in this species. In young honeybees, it reduces the age at which restrained individuals are able to learn an olfactory associative task, whereas in older, free-flying bees, caffeine improves both motivation and cognitive performance in complex learning tasks. Our results suggest that the honeybee model may be useful in explaining caffeine-related behavioural changes not only in this species, but also in mammalian systems.

Does caffeine consumption during pregnancy increase the risk of fetal mortality? A literature review

The aim of this study was to evaluate the available epidemiological evidence of the effect of caffeine consumption during pregnancy on fetal mortality. A systematic qualitative review of observational studies that referred to any source of exposure to caffeine from food in pregnancy and to fetal mortality as the outcome was conducted in the databases MEDLINE and LILACS. Studies published between January 1966 and September 2004 were searched. The following descriptors were used: "caffeine", "coffee", "tea", "cola", and "cacao" to define the exposure and "fetal death", "stillbirth", "fetal demise", and "fetal loss" to define the outcome. The search strategy retrieved 32 publications, but only six met the inclusion criteria and three were included. One more article was found using "see related articles" feature in PubMed. A total of four publications were included in the review. The small number of publications addressing this subject, methodological limitations, inaccurate exposure assessment in all the studies, overall risks only marginally significant in most cases, and the possibility of publication bias preclude stating with certainty that caffeine consumption is actually associated with fetal death.

Influence of caffeine on frequency of hypoglycemia detected by continuous interstitial glucose monitoring system in patients with long-standing type 1 diabetes

OBJECTIVE

The aim of this study was to investigate the effect of caffeine (in doses equivalent to normal daily ingestion) on rates and severity of hypoglycemia in patients with long-standing type 1 diabetes to determine the relationship between caffeine, autonomic function, and hypoglycemia.

RESEARCH DESIGN AND METHODS

Using a double-blinded randomized study, we investigated the effect of caffeine versus placebo in 19 patients with long-standing type 1 diabetes using continuous glucose sensing technology and simultaneous assessment of autonomic function using Holter monitoring.

RESULTS

Caffeine reduced the duration of nocturnal hypoglycemia with a mean duration of 49 minutes (range 0-235) versus 132 (0-468) minutes (P = 0.035). The reduction in duration of nighttime hypoglycemia was due to a decline in the number of episodes of moderate hypoglycemia at the expense of mild hypoglycemic episodes (P = 0.04). There was no overall correlation between reduced heart rate variability (a marker of autonomic dysfunction) and hypoglycemic events (r(s) = 0.12, P = 0.62).

CONCLUSIONS

Our results suggest that caffeine is associated with a significant reduction in nocturnal hypoglycemia. The reduction in nocturnal hypoglycemia was not linked to the concomitant rise in parasympathetic activity associated with caffeine.

Coffee consumption and human health--beneficial or detrimental?--Mechanisms for effects of coffee consumption on different risk factors for cardiovascular disease and type 2 diabetes mellitus

Coffee is probably the most frequently ingested beverage worldwide. Especially Scandinavia has a high prevalence of coffee-drinkers, and they traditionally make their coffee by boiling ground coffee beans and water. Because of its consumption in most countries in the world, it is interesting, from both a public and a scientific perspective, to discuss its potential benefits or adverse aspects in relation to especially two main health problems, namely cardiovascular disease and type 2 diabetes mellitus. Epidemiological studies suggest that consumption of boiled coffee is associated with elevated risk for cardiovascular disease. This is mainly due to the two diterpenes identified in the lipid fraction of coffee grounds, cafestol and kahweol. These compounds promote increased plasma concentration of cholesterol in humans. Coffee is also a rich source of many other ingredients that may contribute to its biological activity, like heterocyclic compounds that exhibit strong antioxidant activity. Based on the literature reviewed, it is apparent that moderate daily filtered, coffee intake is not associated with any adverse effects on cardiovascular outcome. On the contrary, the data shows that coffee has a significant antioxidant activity, and may have an inverse association with the risk of type 2 diabetes mellitus.

Chronic caffeine or theophylline intake during pregnancy inhibits A1 receptor function in the rat brain

The aim of this work was to study whether caffeine or theophylline chronically consumed during pregnancy affect inhibitory adenylyl cyclase pathway mediated by adenosine, in rat brain of both mothers and full-term fetuses. Immunoblotting analysis revealed a significant decrease in alphaGi(1,2) subunit level (27-29% in mothers, 15-18% in fetuses), associated with a significant increase in the mRNA level coding alphaGi(1) in both maternal and fetal rat brain (12-22%) after methylxanthine intake. No significant differences in alphaGi(3) level were detected in any case. On the other hand, forskolin- and forskolin plus guanosine-5'-O(3-thiotriphosphate) tetralithium salt-stimulated adenylyl cyclase activity was significantly decreased (30-36%) in maternal brain. Moreover, adenylyl cyclase inhibition elicited by N(6)-cyclohexyladenosine, specific adenosine A(1) receptor agonist, was also significantly decreased in caffeine- (40.5%) and theophylline- (55.0%) treated mothers, suggesting a desensitization of adenosine A(1) receptor/adenylyl cyclase pathway in maternal brain. However, no significant differences were detected in fetal brain between control and treated animals. Therefore, caffeine or theophylline chronic intake during pregnancy differently modulates inhibitory adenylyl cyclase pathway mediated by adenosine in maternal and fetal brain causing a loss of the system responsiveness only in maternal brain but down-regulating Gi(1) protein in both mother and fetus brain.

Beverage caffeine intake in US consumers and subpopulations of interest: estimates from the Share of Intake Panel survey

Concerns exist about the potential adverse health effects of high consumption of dietary caffeine, especially in children and pregnant women. Recommended caffeine intakes corresponding to no adverse health effects have been suggested recently for healthy adults (400-450 mg/day), for women contemplating pregnancy (300 mg/day), and for young children age 4-6 years (45 mg/day). To determine whether current caffeine intake approaches these levels, intake from major dietary sources (coffee, tea and carbonated soft drinks) were measured in 10,712 caffeinated beverage consumers in the 1999 US Share of Intake Panel, a targeted beverage survey. Mean caffeine intakes in adult caffeinated beverage consumers ranged from 106 to 170 mg/day (90th percentile intake was 227-382 mg/day). In children 1-5 and 6-9 years, mean caffeine intakes were 14 and 22 mg/day, respectively; corresponding 90th percentile intakes were 37 and 45 mg/day. Pregnant women consumed an average of 58 mg/day (157 mg/day at the 90th percentile), and women of reproductive age ingested 91-109 mg/day (229-247 mg/day at the 90th percentile). These data show that while mean caffeine intakes are within recommended safe levels, heavy consumers of certain subpopulations, including young children and women contemplating pregnancy, might benefit from dietary advice.

Associations between coffee consumption and inflammatory markers in healthy persons: the ATTICA study

BACKGROUND

The effect of coffee consumption on the cardiovascular system is conflicting. Inflammation is important to the development of cardiovascular disease (CVD), and several dietary factors are thought to exert significant effects on inflammation and thus on the risk of CVD.

OBJECTIVE

We aimed to investigate the associations between coffee consumption and inflammatory markers.

DESIGN

The cross-sectional survey enrolled 1514 men (x +/- SD age: 46 +/- 13 y; range: 18-87 y) and 1528 women (aged 45 +/- 13 y; range: 18-89 y). Five percent of men and 3% of women were excluded for history of CVD. Fasting blood samples were collected. Dietary habits (including consumption of various types of coffee) were evaluated by using a validated food-frequency questionnaire.

RESULTS

Compared with coffee nondrinkers, men who consumed >200 mL coffee/d had 50% higher interleukin 6 (IL-6), 30% higher C-reactive protein (CRP), 12% higher serum amyloid-A (SAA), and 28% higher tumor necrosis factor alpha (TNF-alpha) concentrations and 3% higher white blood cell (WBC) counts (all: P < 0.05). Women who consumed >200 mL coffee/d had 54% higher IL-6, 38% higher CRP, 28% higher SAA, and 28% higher TNF-alpha concentrations and 4% higher WBC counts (all: P < 0.05) than did coffee nondrinkers. The findings were significant even after control for the interactions between coffee consumption and age, sex, smoking, body mass index, physical activity status, and other covariates.

CONCLUSIONS

A relation exists between moderate-to-high coffee consumption and increased inflammation process. This relation could explain, in part, the effect of increased coffee intake on the cardiovascular system.

Pharmacotherapy for excessive daytime sleepiness

Excessive daytime sleepiness (EDS) has recognized detrimental consequences such as road traffic accidents, impaired psychological functioning and reduced work performance. EDS can result from multiple causes such as sleep deprivation, sleep fragmentation, neurological, psychiatric and circadian rhythm disorders. Treating the underlying cause of EDS remains the mainstay of therapy but in those who continue to be excessively sleepy, further treatment may be warranted. Traditionally, the amphetamine derivatives, methylphenidate and pemoline (collectively sympathomimetic) psychostimulants were the commonest form of therapy for EDS, particularly in conditions such as narcolepsy. More recently, the advent of modafinil has broadened the range of therapeutic options. Modafinil has a safer side-effect profile and as a result, interest in this drug for the management of EDS in other disorders, as well as narcolepsy, has increased considerably. There is a growing school of thought that modafinil may have a role to play in other indications such as obstructive sleep apnea/hypopnea syndrome already treated by nasal continuous positive airway pressure but persisting EDS, shift work sleep disorders, neurological causes of sleepiness, and healthy adults performing sustained operations, particularly those in the military. However, until adequately powered randomised-controlled trials confirm long-term efficacy and safety, the recommendation of wakefulness promoters in healthy adults cannot be justified.

Caffeine ingestion before an oral glucose tolerance test impairs blood glucose management in men with type 2 diabetes

Caffeine ingestion negatively affects insulin sensitivity during an oral glucose tolerance test (OGTT) in lean and obese men, but this has not been studied in individuals with type 2 diabetes. We examined the effects of caffeine ingestion on insulin and glucose homeostasis in obese men with type 2 diabetes. Men (n = 12) with type 2 diabetes (age = 49 +/- 2 y, BMI = 32 +/- 1 kg/m(2)) underwent 2 trials, 1 wk apart, in a randomized, double-blind design. Each trial was conducted after withdrawal from caffeine, alcohol, exercise, and oral hypoglycemic agents for 48 h and an overnight fast. Subjects randomly ingested caffeine (5 mg/kg body weight) or placebo capsules and 1 h later began a 3 h 75 g OGTT. Caffeine increased (P < 0.05) serum insulin, proinsulin, and C-peptide concentrations during the OGTT relative to placebo. Insulin area under the curve was 25% greater (P < 0.05) after caffeine than after placebo ingestion. Despite this, blood glucose concentration was also increased (P < 0.01) in the caffeine trial. After caffeine ingestion, blood glucose remained elevated (P < 0.01) at 3 h postglucose load (8.9 +/- 0.7 mmol/L) compared with baseline (6.7 +/- 0.4 mmol/L). The insulin sensitivity index was lower (14%, P = 0.02) after caffeine than after placebo ingestion. Overall, despite elevated and prolonged proinsulin, C-peptide, and insulin responses after caffeine ingestion, blood glucose was also increased, suggesting an acute caffeine-induced impairment in blood glucose management in men with type 2 diabetes.