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1.
Caffeine is one of the most researched food components, with the vast majority of dietary contributions coming from beverage consumption; however, there is little population-level data on caffeine intakes in the U.S. This study estimated the caffeine intakes of the U.S. population using a comprehensive beverage survey, the Kantar Worldpanel Beverage Consumption Panel. A nationally representative sample of 37,602 consumers (aged ⩾ 2 years) of caffeinated beverages completed 7-day diaries which facilitated the development of a detailed database of caffeine values to assess intakes. Results showed that 85% of the U.S. population consumes at least one caffeinated beverage per day. The mean (±SE) daily caffeine intake from all beverages was 165 ± 1 mg for all ages combined. Caffeine intake was highest in consumers aged 50–64 years (226 ± 2 mg/day). The 90th percentile intake was 380 mg/day for all ages combined. Coffee was the primary contributor to caffeine intakes in all age groups. Carbonated soft drinks and tea provided a greater percentage of caffeine in the younger (<18 years) age groups. The percentage of energy drink consumers across all age groups was low (⩽10%). These data provide a current perspective on caffeinated beverage consumption patterns and caffeine intakes in the U.S. population. 相似文献
2.
Caffeine is an adenosine receptor antagonist that may influence fertility by affecting ovulation, menstrual characteristics, or sperm quality. We studied the association between female and male preconception caffeine intake and fecundability in a North American prospective cohort study of 2135 pregnancy planners. Frequency of caffeinated beverage intake was self-reported at baseline. Outcome data were updated every 8 weeks until reported pregnancy; censoring occurred at 12 months. Adjusted fecundability ratios (FR) and 95% confidence intervals (CI) were estimated using proportional probabilities regression. Total caffeine intake among males, but not females, was associated with fecundability (FR for ≥300 vs. <100 mg/day caffeine among males = 0.72, 95% CI = 0.54–0.96), although the association was not monotonic. With respect to individual beverages, caffeinated tea intake was associated with slight reductions in fecundability among females, and caffeinated soda and energy drink intake were associated with reduced fecundability among males. 相似文献
3.
Karen J. Morgan Vala J. Stults Mary E. Zabik 《Regulatory toxicology and pharmacology : RTP》1982,2(4):296-307
A nationwide, 7-day food consumption survey was utilized to assess average daily consumption of saccharin and caffeine by individuals 5 to 18 years old. The total sample's average daily saccharin and caffeine intakes were 4.1 and 37.4 mg, respectively. Only 14% of the individuals consumed saccharin while 98% consumed caffeine. On days when these dietary components were consumed, average saccharin intake was 87.4 mg and average caffeine intake was 47.9 mg. In general, intake levels of both dietary components increased with increasing age. However, on a body weight basis (mg/kg) caffeine intakes did not increase with increasing age. When expressed as milligrams of caffeine intake per kilogram body weight per day, children 5 to 6 years old had significantly higher intakes (1.1 mg/kg/day) than 7 to 8 year olds. No other age differences were noted. Artificially sweetened carbonated beverages contributed the greatest number of milligrams of saccharin to total intake while tea, followed by carbonated beverages, made the most significant impact on caffeine consumption. Considerable variation was found for both saccharin and caffeine consumption levels among the sample members as well as for each individual during the 7 days surveyed. 相似文献
4.
Maaike Bilau Christophe Matthys Christine Vinkx Stefaan De Henauw 《Food and chemical toxicology》2008,46(2):717-723
An exposure assessment was performed to estimate the daily intake of benzoates for the Flemish population. Three age groups were considered: preschool children (n=697; age 2-6; 3-day estimated dietary record), adolescents (n=341; age 14-18; 7-day estimated dietary record) and women (n=641; age 18-40; 2-day estimated dietary record). In a first step in the risk evaluation process as proposed by the European Union, the individual food consumption data were multiplied with the maximum permitted use levels for benzoates per food group. The median (interquartile range) estimated daily intake is, respectively, 2.0 (1.0-3.2) mg/kg bw, 1.7 (1.1-2.7) mg/kg bw and 1.92 (1.3-3.0) mg/kg bw for preschool children, adolescents and adult women. In all age groups, the greatest potential contributor to the total estimated benzoate intake was the group of non-alcoholic flavoured drinks. At respectively the 92nd percentile (children), the 97th percentile (adolescents) and the 94th percentile (women), the accepted daily intake (ADI) of 5mg/kg bw/day is exceeded slightly. However, this approach, in which the maximum permitted use levels are used is known to overestimate the intake, since not all food items in which benzoates are allowed, contain (the maximum permitted use level of) benzoates. A more precise estimation, using actual levels, is recommended. 相似文献
5.
Tatsuya Yoshihara Masayoshi Zaitsu Fumie Shiraishi Hisatomi Arima Fumi Takahashi-Yanaga Masaki Arioka Shunichi Kajioka Toshiyuki Sasaguri 《Journal of pharmacological sciences》2019,139(3):209-214
The aim of this study was to investigate the contribution of gene polymorphisms, in combination with habitual caffeine consumption, to the effect of caffeine intake on hemodynamic and psychoactive parameters. A double-blind, prospective study was conducted with 201 healthy volunteers randomly allocated 2:1 to the caffeinated group (150 mL decaffeinated coffee with additional 200 mg caffeine) or decaffeinated group (150 mL decaffeinated coffee). We measured the changes in blood pressure (BP) and calculation speed upon coffee intake, stratifying with gene polymorphisms, e.g., those in adenosine A2A receptor (ADORA2A) and cytochrome P450 (CYP) 1A2, and daily caffeine consumption (≤90 mg/day and >90 mg/day). Overall, caffeine intake independently increased BP and calculation speed (p-values < 0.05), irrespective of the polymorphisms. In stratified analysis, a statistical significance within the caffeinated group was observed for the change in systolic BP in the stratum of CYP1A2 polymorphism with daily caffeine consumption ≤90 mg/day: change in systolic BP in the CYP1A2 rs762551 CC group (mean ± SD = 11.8 ± 5.9) was higher than that in the AA/CA group (4.1 ± 5.5). Gene polymorphisms may limitedly modify the effect of caffeine intake on hemodynamic parameters in combination with habitual caffeine consumption. 相似文献
6.
Rationale: The effects of caffeine, especially caffeinated coffee, on human performance have been extensively studied. However, few studies
have been naturalistic representations of how tea/coffee is normally consumed in terms of dose and time of consumption. Objectives: This study investigated the effects of day-long consumption of tea, coffee and water on cognitive and psychomotor performance,
and sleep quality at night. Methods: Thirty healthy volunteers received equal volume drinks equivalent to either 1 or 2 cups of tea (containing 37.5 mg or 75
mg caffeine), or coffee (75 mg or 150 mg caffeine), or water, in a randomised five-way crossover design. Drinks were administered
on four occasions during the day (0900, 1300, 1700 and 2300 hours). A psychometric battery consisting of critical flicker
fusion (CFF), choice reaction time (CRT) and subjective sedation (LARS) tests, was administered pre-dose and at frequent time
points post-dose. The Leeds Sleep Evaluation Questionnaire (LSEQ) was completed each morning and a wrist actigraph was worn
for the duration of the study. Results: Caffeinated beverages maintained CFF threshold over the whole day (P<0.05), independent of caffeine dose or beverage type. During the acute phase of beverage ingestion, caffeine significantly
sustained performance compared to water after the first beverage for CFF and subjective sedation (P<0.05), and after the second beverage for the Recognition component of the CRT task (P<0.05). Additionally, there were significant differences between tea and coffee at 75 mg caffeine after the first drink. Compared
to coffee, tea produced a significant increase in CFF threshold between 30 and 90 min post-consumption (P<0.01). However, following the second beverage caffeinated coffee at 75 mg significantly improved reaction time (P<0.05), compared to tea at the same dose, for the Recognition component of the CRT task. Caffeinated beverages had a dose
dependent negative effect on sleep onset (P<0.001), sleep time (P<0.001) and sleep quality (P<0.001). Conclusions: These results indicate that ingestion of caffeinated beverages may maintain aspects of cognitive and psychomotor performance
throughout the day and evening when caffeinated beverages are administered repeatedly. This study also demonstrates that day-long
tea consumption produces similar alerting effects to coffee, despite lower caffeine levels, but is less likely to disrupt
sleep. Other differences between tea and coffee were more subtle, and require further investigation.
Received: 16 February 1999 / Final version: 20 December 1999 相似文献
7.
Shahid Parvez Amanda M. Evans Matthew Lorber Belinda S. Hawkins Jeffery C. Swartout Linda K. Teuschler Glenn E. Rice 《Regulatory toxicology and pharmacology : RTP》2013
EPA recommends sensitivity analyses when applying the toxic equivalency factor (TEF) method to evaluate exposures to dioxin-like compounds (DLCs). Applying the World Health Organization’s (WHO) 2005 TEF values and estimating average U.S. daily dietary intakes of 25 DLCs from eight food categories, we estimate a toxic equivalency (TEQ) intake of 23 pg/day. Among DLCs, PCB 126 (26%) and 1,2,3,7,8-PeCDD (23%) dominate TEQ intakes. Among food categories, milk (14%), other dairy (28%), beef (25%), and seafood (18%) most influenced TEQ intakes. We develop two approaches to estimate alternative TEF values. Based on WHO’s assumption regarding TEF uncertainty, Approach1 estimates upper and lower TEFs for each DLC by multiplying and dividing, respectively, its individual TEF by ± half a log. Based on compiled empirical ranges of relative potency estimates, Approach2 uses percentile values for individual TEFs. Total TEQ intake estimates using the lower and upper TEFs based on Approach1 were 8 and 68 pg TEQ/day, respectively. The 25th and 75th percentile TEFs from Approach2 yielded 12 and 28 pg TEQ/day, respectively. The influential DLCs and food categories remained consistent across alternative TEFs, except at the 90th percentile using Approach2. We highlight the need for developing underlying TEF probability distributions. 相似文献
8.
Recent reports on caffeine intakes in the United States have highlighted the importance of obtaining accurate and valid measures of caffeine exposure. The objective of this study is to compare two methods of assigning caffeine values to beverages: brand-specific values versus an aggregate single value representing a broader range of products within a beverage category (i.e., category-specific). The two methods yielded some small, but statistically significant differences in the estimation of caffeine intake from coffee, tea, and carbonated soft drinks (CSDs) for all ages combined and within several of the adult age groups (i.e., 35–49, 50–64, and ≥65 years). These differences, while small, suggest that detailed brand-specific data, particularly for CSDs, commercially pre-packaged or bottled teas, coffee, and specialty coffee drinks, provide more accurate estimates of caffeine exposure for some age groups. Despite these differences, these data provide some assurance that studies using a single aggregate caffeine value provide reasonable measures of caffeine exposure, particularly for studies conducted over a decade ago when there were fewer caffeinated products and brand-specific data available. As the caffeinated beverage marketplace continues to evolve, the use of more detailed, brand-specific data will likely strengthen the assessment of caffeine exposure in the United States. 相似文献
9.
Acute caffeine administration has physiological, behavioral, and subjective effects. Despite its widespread use, few studies have described the impact of caffeine consumption in children and adolescents. The purpose of this study was to investigate the effects of acute caffeine administration in adolescents. We measured cardiovascular responses and snack food intake after acute administration of 0 mg, 50 mg, 100 mg, and 200 mg of caffeine. We also compared usual food intake and subjective effects of caffeine between high- and low-caffeine consumers. Finally, we conducted a detailed analysis of caffeine sources and consumption levels. We found main effects of caffeine dose on heart rate (HR) and diastolic blood pressure (DBP), with HR decreasing and DBP increasing with increasing caffeine dose. There were significant interactions among gender, caffeine use, and time on DBP. High caffeine consumers (>50 mg/day) reported using caffeine to stay awake and drinking coffee, tea, soda, and energy drinks more than low consumers (<50 mg/day). Boys were more likely than girls to report using getting a rush, more energy, or improved athletic performance from caffeine. Finally, when we examined energy and macronutrient intake, we found that caffeine consumption was positively associated with laboratory energy intake, specifically from high-sugar, low-fat foods and also positively associated with protein and fat consumption outside of the laboratory. When taken together, these data suggest that acute caffeine administration has a broad range of effects in adolescents and that the magnitude of these effects is moderated by gender and chronic caffeine consumption. 相似文献
10.
Tsuji JS Yost LJ Barraj LM Scrafford CG Mink PJ 《Regulatory toxicology and pharmacology : RTP》2007,48(1):59-68
Background exposures provide perspective for interpreting calculated health risks associated with naturally occurring substances such as arsenic. Background inorganic arsenic intake from diet and water for children (ages 1-6 years) and all ages of the U.S. population was modeled stochastically using consumption data from USDA, published data on inorganic arsenic in foods, and EPA data on arsenic in drinking water. Mean and 90th percentile intakes for the U.S. population were 5.6 and 10.5 microg/day, assuming nationwide compliance with the 10 microg/L U.S. drinking water standard. Intakes for children were slightly lower (3.5 and 5.9 microg/day). Based on the current EPA cancer slope factor for arsenic, estimated lifetime risks associated with background diet and water at the mean and 90th percentile are 1 per 10,000 and 2 per 10,000, respectively. By comparison, reasonable maximum risks for arsenic in soil at 20 (higher typical background level) and 100mg/kg are 4 per 100,000 and 2 per 10,000, using EPA default exposure assumptions. EPA reasonable maximum estimates of arsenic exposure from residential use of treated wood are likewise within background intakes. These examples provide context on how predicted risks compare to typical exposures within the U.S. population, thereby providing perspective for risk communication and regulatory decision-making on arsenic in the environment and in consumer products. 相似文献
11.
This report evaluates the scientific literature on caffeine with respect to potential cardiovascular outcomes, specifically relative risks of total cardiovascular disease (CVD), coronary heart disease (CHD) and acute myocardial infarction (AMI), effects on arrhythmia, heart failure, sudden cardiac arrest, stroke, blood pressure, hypertension, and other biomarkers of effect, including heart rate, cerebral blood flow, cardiac output, plasma homocysteine levels, serum cholesterol levels, electrocardiogram (EKG) parameters, heart rate variability, endothelial/platelet function and plasma/urine catecholamine levels.Caffeine intake has been associated with a range of reversible and transient physiological effects broadly and cardiovascular effects specifically. This report attempts to understand where the delineations exist in caffeine intake and corresponding cardiovascular effects among various subpopulations. The available literature suggests that cardiovascular effects experienced by caffeine consumers at levels up to 600 mg/day are in most cases mild, transient, and reversible, with no lasting adverse effect. The point at which caffeine intake may cause harm to the cardiovascular system is not readily identifiable in part because data on the effects of daily intakes greater than 600 mg is limited. However, the evidence considered within this review suggests that typical moderate caffeine intake is not associated with increased risks of total cardiovascular disease; arrhythmia; heart failure; blood pressure changes among regular coffee drinkers; or hypertension in baseline populations. 相似文献
12.
Caffeine is the world's most widely consumed drug with its main source found in coffee. We evaluated the caffeine content of caffeinated and decaffeinated specialty coffee samples obtained from coffee shops. Caffeine was isolated from the coffee by liquid-liquid extraction and analyzed by gas chromatography with nitrogen-phosphorus detection. In this study, the coffees sold as decaffeinated were found to have caffeine concentrations less than 17.7 mg/dose. There was a wide range in caffeine content present in caffeinated coffees ranging from 58 to 259 mg/dose. The mean (SD) caffeine content of the brewed specialty coffees was 188 (36) mg for a 16-oz cup. Another notable find is the wide range of caffeine concentrations (259-564 mg/dose) in the same coffee beverage obtained from the same outlet on six consecutive days. 相似文献
13.
Rationale. Previous studies have shown that caffeine can reinforce flavour liking in overnight deprived moderate caffeine consumers
(e.g. average of 250 mg/day) but not in low consumers (<120 mg/day). However, it is not possible to determine whether the
difference between moderate and low caffeine consumers results from pre-existing individual differences in response to caffeine,
or results directly from the different amounts of caffeine they habitually consume. If the former were true, then moderate
consumers who are completely withdrawn should still manifest the flavour conditioning effect. Conversely, if the latter were
true, consumers who are completely withdrawn should not manifest the effect.
Objectives. To examine whether moderate caffeine consumers who have been fully withdrawn from caffeine manifest the flavour conditioning
effect.
Methods. In a double-blind study, 48 moderate caffeine consumers refrained from consuming caffeine for 4 weeks and were given replacement
drinks to consume, which were either caffeinated (maintained group) or decaffeinated (withdrawn group). In the final 2 weeks,
all subjects evaluated a novel drink containing either 100 mg caffeine or placebo on four non-consecutive days.
Results. The rated pleasantness of the novel drink containing caffeine increased over the four test days in the group maintained on
caffeine, but pleasantness of the same drink fell significantly in the withdrawn group.
Conclusions. These data suggest that the ability of caffeine to reinforce changes in flavour liking are driven by the alleviation of withdrawal
symptoms among habitual caffeine consumers and provide further support for the negative reinforcement theory.
Electronic Publication 相似文献
14.
Behavioral dependence on caffeine and phencyclidine in rhesus monkeys: interactive effects 总被引:1,自引:0,他引:1
M E Carroll E W Hagen M Asencio L H Brauer 《Pharmacology, biochemistry, and behavior》1988,31(4):927-932
Five rhesus monkeys were trained to self-administer orally-delivered phencyclidine (PCP) and water under concurrent fixed-ratio (FR) 8 schedules. Liquid deliveries were contingent upon lip-contact responses on solenoid-operated drinking spouts, and food pellet delivery was contingent upon responses on a centrally-located lever. Food was available during three 1-hr periods each day under an FR 64 or FR 80 schedule. The liquids were available during three 6.5-hr periods after each food component. In the first experiment caffeine (4 or 8 mg) was added to each 6-g food pellet, and after responding stabilized, noncaffeinated pellets were substituted for the caffeinated pellets for eight days. There were no differences in food-, water- or PCP-maintained behavior due to caffeine concentration (4 vs. 8 mg/pellet) although the monkeys consumed twice as much caffeine at the higher concentration. Food-maintained responding was reliably reduced by 25-50 percent the first day of caffeine removal, and there was a recovery of responding characterized by intermittent cycles of low response rates over the next 7 days. Water and PCP intake were not systematically disrupted when caffeine access was terminated. In the second experiment the monkeys were tested with caffeinated (6 mg/pellet) and noncaffeinated pellets under conditions of PCP removal (water substitution) and reinstatement. Under both food conditions, when PCP access was terminated, pellet deliveries decreased by about 50 percent and gradually recovered over the 8-day water substitution phase. However, behavioral disruptions were more severe under conditions in which monkeys received caffeinated pellets, suggesting an interactive effect due to termination of PCP access and decreased caffeine intake. These results indicate that disruptions in operant baselines are sensitive indicators of the effects of discontinuing caffeine access; however, the severity and time course of behavioral disruptions due to caffeine removal are considerably less than after termination of PCP access. 相似文献
15.
Peter J Rogers Christa Hohoff Susan V Heatherley Emma L Mullings Peter J Maxfield Richard P Evershed J��rgen Deckert David J Nutt 《Neuropsychopharmacology》2010,35(9):1973-1983
Caffeine, a widely consumed adenosine A1 and A2A receptor antagonist, is valued as a psychostimulant, but it is also anxiogenic. An association between a variant within the ADORA2A gene (rs5751876) and caffeine-induced anxiety has been reported for individuals who habitually consume little caffeine. This study investigated whether this single nucleotide polymorphism (SNP) might also affect habitual caffeine intake, and whether habitual intake might moderate the anxiogenic effect of caffeine. Participants were 162 non-/low (NL) and 217 medium/high (MH) caffeine consumers. In a randomized, double-blind, parallel groups design they rated anxiety, alertness, and headache before and after 100 mg caffeine and again after another 150 mg caffeine given 90 min later, or after placebo on both occasions. Caffeine intake was prohibited for 16 h before the first dose of caffeine/placebo. Results showed greater susceptibility to caffeine-induced anxiety, but not lower habitual caffeine intake (indeed coffee intake was higher), in the rs5751876 TT genotype group, and a reduced anxiety response in MH vs NL participants irrespective of genotype. Apart from the almost completely linked ADORA2A SNP rs3761422, no other of eight ADORA2A and seven ADORA1 SNPs studied were found to be clearly associated with effects of caffeine on anxiety, alertness, or headache. Placebo administration in MH participants decreased alertness and increased headache. Caffeine did not increase alertness in NL participants. With frequent consumption, substantial tolerance develops to the anxiogenic effect of caffeine, even in genetically susceptible individuals, but no net benefit for alertness is gained, as caffeine abstinence reduces alertness and consumption merely returns it to baseline. 相似文献
16.
Ofir Turel 《Substance use & misuse》2018,53(12):2089-2092
Background: Energy drinks have been repeatedly blamed for contributing to caffeine intake among teenagers. Objectives: This study aimed to estimate and compare the caffeine intake of US teenagers from soda drinks versus energy drinks and shots. Methods: Data were taken from a 2015 nationally representative survey (Monitoring the Future) of 8th and 10th graders in the US (47.2% 8th grade; 51.1% female). Participants reported their numbers of consumed sodas, diet sodas, energy drinks, and energy shots per day. These were converted into mg caffeine/day and were contrasted with common guidelines for healthy caffeine intake, stratified by age group and sex. Error-bar charts, ANOVA and ROC curves were used for contrasting caffeine intake from soda drinks and energy drinks, as well as their contribution to exceeding recommended caffeine intake cutoffs. Results: First, in both sexes and grades the intake from soda drinks was significantly higher than the intake from energy drinks. The soda and energy drink intake for males was higher than the intake for females; intake for 8th graders was higher than this of 10th graders. Second, caffeine intake from soda drinks was significantly higher even in those who exceeded the recommended maximum caffeine intake. Third, caffeine intakes from soda and energy drinks were efficacious in explaining the exceeding of the recommended threshold for daily caffeine intake, but the explanatory power of soda drinks was larger. Conclusions: From a caffeine consumption standpoint, health professionals should emphasize reduction in both soda and energy drinks. 相似文献
17.
T. F. X. Collins J. J. Welsh T. N. Black D. I. Ruggles 《Food and chemical toxicology》1983,21(6):763-777
Caffeine dissolved in drinking-water was available ad lib. to Osborne Mendel rats at dose levels of 0, 0.007, 0.018, 0.036, 0.07, 0.10, 0.15 or 0.20% during days 0–20 of gestation. The corresponding daily caffeine intakes were 0, 10.1, 27.4, 50.7, 86.6, 115.8, 160.9 and 204.5 mg/kg body weight. Dosages of 160.9 and 204.5 mg/kg were associated with decreased implantation efficiency, increased resorptions and decreased mean numbers of viable foetuses. Numbers of runts were significantly increased after dosages of 115.8–204.5 mg/kg/day. Foetal body weight and length were decreased and oedematous foetuses were increased at dosages of 86.6–204.5 mg/kg/day. Contrary to results seen after gavage studies, caffeine available ad lib. in drinking-water produced no dose-related gross anomalies. Only two animals with missing or hypoplastic nails were produced, both in the 160.9-mg/kg group. Sternebral ossification deficiencies were increased at all dose levels except 10.1 mg/kg/day. Skeletal ossification deficiencies were increased in a dose-related manner at the four highest dose levels. Caffeine given by water bottle produced ossification deficiencies similar to those seen after intubation, but at higher dosages. 相似文献
18.
Nineteen healthy volunteers ingested 400 ml black tea, coffee, caffeinated water, decaffeinated tea or plain water on three
occasions through the day (0900, 1400 and 1900 hours). A 2 × 2 factorial design with caffeine (0, 100 mg) and beverage type
(water, tea) was employed, with coffee (100 mg caffeine) as a positive internal control, based on a five-way crossover. A
psychometric test battery comprising critical flicker fusion (CFF), choice reaction time (CRT), short-term memory (STM) and
subjective sedation (LARS) was performed at regular intervals throughout the day, and intensively so immediately following
each beverage. Consumption of tea compared to water was associated with transient improvements in performance (CFF) within
10 min of ingestion and was not affected by the time of day. Caffeine ingestion was associated with a rapid (10 min) and persistent
reduction in subjective sedation values (LARS), again independent of time of day, but did not acutely alter CFF threshold.
Over the whole day, consumption of tea rather than water, and of caffeinated compared to decaffeinated beverages, largely
prevented the steady decline in alertness (LARS) and cognitive capacity observed with water ingestion. The effects of tea
and coffee were similar on all measures, except that tea consumption was associated with less variation in CFF over the whole
day. No significant treatment effects were apparent in the data for the STM. Tea ingestion is associated with rapid increases
in alertness and information processing capacity and tea drinking throughout the day largely prevents the diurnal pattern
of performance decrements found with the placebo (no caffeine) condition. It appears that the effects of tea and coffee were
not entirely due to caffeine per se; other factors either intrinsic to the beverage (e.g. sensory attributes or the presence
of other biologically active substances) or of a psychological nature (e.g. expectancy) are likely to play a significant role
in mediating the responses observed in this study.
Received: 18 September 1997/Final version: 16 February 1998 相似文献
19.
Psychopharmacological studies using caffeinated beverages or caffeine have rarely considered temporal effects on psychological
and physiological function or the specific contribution of caffeine, hot water, or beverage type to the observed effects.
The effect of 400 ml hot tea, coffee, and water consumption on systolic and diastolic blood pressure (SBP and DBP), heart
rate, skin conductance (a measure of sympathetic nervous system activation), skin temperature, salivary cortisol, and mood
were monitored in 16 healthy caffeine-withdrawn (14 h) subjects in a complete crossover design. Beverages were ingested with/without
100 mg caffeine and milk (tea/coffee only). Hot beverage ingestion rapidly increased skin conductance and temperature (+1.7°C) with peak effects observed only 10–30 min post-consumption. Caffeine
in the beverage rapidly augmented skin conductance responses but, in contrast to the effect of hot water, reduced the skin
temperature response and increased SBP (+2.8 mmHg) and DBP (+2.1 mmHg) 30–60 min post-consumption. Both caffeine and milk
addition to beverages independently improved mood and reduced anxiety 30 and 60 min post-consumption. Milk addition had no
other effects apart from attenuating the transient increase in physiological responses associated with the drinking phase.
There were no effects of beverage consumption on salivary cortisol or of beverage vehicle on salivary caffeine levels, the
latter indicating that caffeine pharmacokinetics was similar in both tea and coffee, and not different from caffeinated water.
In keeping with this, the responses to tea and coffee ingestion were similar and largely accounted for by the effects of hot
water and caffeine. However, tea potentiated the increase in skin temperature compared to coffee and water indicative of a
greater vasodilatory response plausibly related to the presence of flavonoids in tea. We conclude that ingestion of hot caffeinated
beverages stimulates physiological processes faster than hitherto described, primarily via the effects of hot water and caffeine,
but with beverage type and milk playing important modulatory roles.
Received: 15 March 1997/Final version: 23 May 1997 相似文献
20.
In 1998 and 1999, wheat contained high levels of deoxynivalenol (DON) in The Netherlands. Eighty percent of the 1-year-old children exceeded the TDI (20% exceeded 2TDI). Assuming a long-term intake a negative effect on body weight might be possible. In 1999 the Dutch government took several risk management measures. We performed a probabilistic exposure and effect assessment and compared current and previous DON exposure and potential health effects for young children. The DON contamination of wheat was reduced for 50%. The estimated DON-intake was reduced to one-third of the previous levels. One-year-old children showed the highest DON-intake with a median of 0.46 microg/kgbw/day (95th percentile: 1.00 microg/kgbw/day). The probabilistic effect assessment showed that at the 95th percentile of DON-intake a reduced body weight was unlikely to exceed 9%. Taking into account the possible (partly) reversibility of this effect we conclude that no clear adverse health effects will be associated to the exposure (February 2000-December 2002) to DON in The Netherlands. 相似文献