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1.
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   

2.
The caffeine content of 10 energy drinks, 19 carbonated sodas, and 7 other beverages was determined. In addition, the variability of the caffeine content of Coca-Cola fountain soda was evaluated. Caffeine was isolated from the samples by liquid-liquid extraction and analyzed by gas chromatography with nitrogen-phosphorus detection. The caffeine concentration of the caffeinated energy drinks ranged from none detected to 141.1 mg/serving. The caffeine content of the carbonated sodas ranged from none detected to 48.2 mg/serving, and the content of the other beverages ranged from < 2.7 to 105.7 mg/serving. The intra-assay mean, standard deviation, and % coefficient of variation for the Coca-Cola fountain samples were 44.5, 2.95, and 6.64 mg/serving, respectively.  相似文献   

3.
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   

4.
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   

5.

Objective

The mixing of alcoholic beverages with caffeine has been identified as a public health problem among college students; however, little is known about the consumption of such drinks among younger adolescents. We estimated the prevalence of caffeinated alcoholic beverage (CAB) use among a wide age range of underage drinkers, examined differences in traditional (i.e. self-mixed alcoholic beverages with soda, coffee and tea) and non-traditional CAB use (pre-mixed caffeinated alcoholic beverages or self-mixed alcoholic beverages with energy drinks or energy shots) among underage drinkers by age and other demographic characteristics, and examined differences in hazardous drinking behavior between CAB and non-CAB users.

Methods

We used an existing Internet panel maintained by Knowledge Networks, Inc. to assess the use of pre-mixed and self-mixed CABs in the past 30 days among a national sample of 1031 youth drinkers age 13–20. We conducted logistic regression analyses to estimate the relationship between traditional and non-traditional CAB use and risky drinking behavior as well as adverse outcomes of drinking, while controlling for age, gender, race/ethnicity, income, and general risk-taking (seat belt use).

Results

The overall prevalence of CAB use in the sample of underage drinkers was 52.4% (95% confidence interval [CI], 47.4%–57.4%). CAB prevalence was 48.4% among 13–15 year-old drinkers, 45.3% among 16–18 year-old drinkers, and 58.4% among 19–20 year-old drinkers. After controlling for other variables, we found a continuum of risk with non-traditional CAB use most significantly associated with binge drinking (odds ratio [OR] = 6.3), fighting (OR = 4.4), and alcohol-related injuries (OR = 5.6).

Conclusions

The problem of caffeinated alcoholic beverage use is not restricted to college-aged youth. The prevalence of CAB use among underage drinkers is higher than previously thought and begins in early adolescence. Adolescents who consume CABs, and particularly non-traditional CABs, are at increased risk of adverse outcomes.  相似文献   

6.

Background

Soda manufacturers claim that caffeine is added to soda as a flavor enhancer, but many researchers have speculated that caffeine is added to increase the hedonic and reinforcing properties of the soda. Studies in adults have demonstrated that caffeine can condition flavor preferences when added to novel-flavored beverages.

Objectives

The purpose of this study was to test the hypothesis that caffeine added to novel-flavored drinks would increase liking and preference in adolescents.

Methods

Adolescents (n?=?99) between the ages of 12 and 17 rated and ranked seven novel soda drinks. They were then randomly assigned to consume one of these beverages paired with either caffeine (1 or 2 mg/kg) or placebo over four consecutive days and rate liking. On the final visit, participants retasted the seven beverages and provided hedonic ratings and rankings.

Results

Participants in the 2-mg/kg caffeine group increased the liking of the beverage over the exposure period after an initial decrease, but there was no change in liking for those in the placebo group or in the 1-mg/kg group. The increase in liking in the 2-mg/kg group was accompanied by a decrease in perceived bitterness, but no change in beverage ranking or consumption during the post-test.

Conclusions

Caffeine added to novel beverages results in a decrease in liking followed by an increase in liking with repeated exposures that may result from habituation to the bitterness of caffeine. Change in bitter perception may be the mechanism by which adolescents establish regular caffeine use.  相似文献   

7.
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   

8.
ABSTRACT

Background: Previous research has consistently shown the negative impact that peers can have on adolescent substance use patterns. Few studies have examined the positive influence adolescents can have on their peers. This study aimed to examine the relationship of positive peer influence with indices of substance use and also to compare abstinent adolescents and substance-using adolescents on positive peer influence. Method: One hundred fifty-four adolescents (age range 12–20 years) completed a questionnaire on positive peer influence and other correlates of adolescent substance use including mental health, family functioning, and social support. Results: Positive peer influence was a significant predictor of lower substance use behaviors in adolescents, with positive influence from close friends being the strongest predictor. Substance-using adolescents' scores were significantly different from abstinent adolescents' scores for positive peer support, mental health functioning, impulsivity, and social support. Conclusions: These results indicate that positive influence from adolescents' peers may act as a protective factor in substance use. This influence should be utilized to aid the design of prevention and intervention initiatives in adolescent substance use.  相似文献   

9.
Rationale: A neutral stimulus repeatedly paired with administration of a drug may elicit a conditioned response. This process, termed pharmacological classical conditioning, may be important in the understanding of placebo effects. Objective: The unconditioned response to caffeine is increased physiological and psychological arousal. The present study investigated whether stimuli associated with the use of caffeine, i.e. the smell and taste of coffee, elicited a conditioned increase in arousal. It was also investigated whether conditioned arousal modulated the unconditioned arousal induced by caffeine. Methods: Twenty subjects who drank at least two cups of coffee per day were exposed to four conditions in a within-subjects design, where the subjects received coffee or orange juice crossed with placebo or 2 mg/kg caffeine. Dependent variables were skin conductance responses and startle reflexes to 85 dB noise bursts, skin conductance levels, blood pressure, heart rate, and subjective measures of arousal. Results: Both caffeine (caffeinated juice) and caffeine-associated stimuli (decaffeinated coffee) increased subjective and physiological arousal. When caffeine and caffeine-associated stimuli were presented together (caffeinated coffee), a non-significant tendency towards an additive effect of the conditioned arousal on the unconditioned arousal to caffeine was seen in some dependent variables. Conclusions: Presentation of caffeine-associated stimuli to caffeine-users elicited conditioned responses similar to the unconditioned drug response. Thus, presentation of caffeine-associated stimuli could be used as an experimental model of placebo effects. Received: 23 November 1998/Final version: 16 February 1999  相似文献   

10.
Background: Adolescent substance use is a significant public health concern due to its prevalence and associated negative consequences. Although many adolescents use substances, there is substantial heterogeneity in their use patterns. Identifying risk and protective factors that differentiate adolescents with different substance use profiles is important for preventing negative consequences for those at risk. Objective: This study identified distinct latent profiles of substance use by considering adolescents' involvement in multiple common and illicit substances as well as related problems and examined the extent to which individual and contextual factors in the family, peer, school, and neighborhood environments were related to adolescents' membership of substance use profiles. Method: Data came from 9,155 high school students (51% female; 74% European American) who completed electronic surveys in the 2009 Dane County Youth Assessment (DCYA). Latent class analysis (LCA) was conducted to identify profiles of adolescent substance involvement and related problems. Multinomial logistic regression was conducted to examine associations between individual and contextual factors and latent class membership. Results: LCA identified four distinct profiles of adolescent substance use characterized by both licit and illicit substance use and related problems: Abstainers (56.3%), Alcohol-only users (25.6%), Alcohol-cigarette-marijuana users (13.8%), and Problem polysubstance users (4.3%). Controlling for demographics, individual and contextual factors were associated with adolescents' likelihoods of membership in substance use profiles; notably, the associations varied to some extent across substance use profiles. Conclusions: Substance use is heterogeneous among adolescents. Effects of risk and protective factors on substance use vary depending on adolescents' substance use patterns.  相似文献   

11.
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   

12.
Objectives: This research explores the relationship between parental immigration-related trauma and second-generation adolescent substance abuse. To examine this relationship, we focused on Ethiopian adolescents in Israel who are at risk for substance abuse. Many immigrants from Ethiopia experienced severe immigration trauma and research indicates the existence of transgenerational trauma transmission. The current research focuses on the connection between Ethiopian adolescents' perceptions of their parents' immigration trauma and their readiness to use psychoactive substances. Design: Five hundred and ten second-generation Ethiopian adolescents (Israeli-born children of Ethiopian immigrants) filled out questionnaires examining socio-demographic characteristics, immigration impact and readiness to consume alcoholic beverages and use illegal drugs. Results: Our findings show that readiness levels among Ethiopian adolescents to use psychoactive substances are relatively low, and that parental trauma only affects the readiness to consume alcohol. The levels of readiness to consume drugs were partially related to parental trauma. Conclusions/Importance: Transgenerational trauma transmission should be considered when implementing alcohol and substance abuse treatment and prevention policies among second generation immigrants. This should be done on all levels including personal, interpersonal and community levels.  相似文献   

13.
RATIONALE: Caffeine is present in a wide variety of beverages, often together with a number of other ingredients, such as sugars, taurine, glucuronolactone and vitamins. However, the majority of psychopharmacological studies have used pure caffeine tablets or drinks with doses in excess of those normally consumed in daily life. In addition, all the participants are usually deprived of caffeine for 10 h or more before the study. Consequently, it has been argued that any improvement in performance is only due to a reversal of caffeine withdrawal. OBJECTIVE: The present two studies tested participants who had minimal deprivation from caffeine (an hour or less) with an 80-mg caffeinated (80 mg/250 ml), taurine-containing beverage (commercially available) verum, which also contained sugars, glucuronolactone and vitamins. The placebos in the two studies were a sugar-free and a sugar-containing drink, in order to examine the effects of the sugar. METHODS: In total, 42 participants were tested with a rapid visual information test, a verbal reasoning test, a verbal and non-verbal memory test and a set of mood measures. Prior to testing, they were allowed ad libitum caffeinated beverages until 1 h before testing (study 1) and unrestricted caffeine use before testing (study 2). RESULTS: In both studies, the caffeinated, taurine-containing beverage produced improved attention and verbal reasoning, in comparison with a sugar-free and the sugar-containing drinks. The improvement with the verum drink was manifested in terms of both the mean number correct and the reaction times. Another important finding was the reduction in the variability of attentional performance between participants. No effects on memory were found. There were no differences in performance between the glucose and sugar-free drinks. CONCLUSIONS: Moderate doses of caffeine and taurine can improve information processing in individuals who could not have been in caffeine withdrawal.  相似文献   

14.
Abstract

The present study examined the potentially mediating effect of alcohol expectancies and moderating effect of acculturation on the relationship between peer alcohol use and Latino adolescent alcohol use. Participants were 115 adolescents recruited through alternative schools, community events, a community psychologist, and Latino groups at a midwestern university. Questionnaires in this study assessed adolescents' perceptions about both their own and their peers' alcohol use in addition to their expectancies about the effects of alcohol, and their level of acculturation. Demographic characteristics of the sample were also assessed in order to control for their possible effects (e.g., age, gender). Results from the present study indicated that a higher level of peer alcohol use was associated with a higher level of adolescent alcohol use. Additionally, adolescents' expectancies about the effect of alcohol on their social behavior mediated the relationship between peer alcohol use and adolescent alcohol use. Results support previous research suggesting the importance of peers as role models for Latino adolescent alcohol use. Acculturation did not moderate the relationship between peer and adolescent alcohol use. The present study adds understanding as to how Latino adolescents' beliefs regarding alcohol use may influence the relationship between peer alcohol use and adolescent alcohol use.  相似文献   

15.
Background: Growing moves in the U.S. toward relaxed laws surrounding adult use of marijuana raise concerns about concurrent increases in adolescent use of marijuana. Objectives: This study collected and analyzed primary data on the relationship between marijuana legalization status in U.S. states and adolescents' marijuana use. Methods: Recruited through social networking sites and youth-services community agencies, a sample of 1,310 adolescents from 48 U.S. states and the District of Columbia reported their use of marijuana. Youths' use rates were compared with the marijuana legalization status of youths' states of residence. Results: Study findings failed to show a relationship between adolescents' use of marijuana and state laws regarding marijuana use. Relationships were found for increased marijuana use by older youths, females, and non-Hispanic youths. Youths whose parents completed 2 or more years of college were less likely to report marijuana use than those whose parents completed fewer than 2 years of college. Conclusions: Albeit study findings do not support predictions of growing marijuana use by adolescents in states with liberalized adult use laws, further monitoring of adolescents' use with larger and more representative samples is needed.  相似文献   

16.
Previous research has demonstrated that caffeinated beverage consumption predicts alcohol consumption among early adolescents. This study aimed to investigate this association in two ways: (1) by examining if this association remained significant once other established risk factors for alcohol were adjusted for statistically; and (2) by considering three possible moderators of this association: gender, sensation-seeking, and parental monitoring. Data from the Camden Youth Development Study, a longitudinal, community-based study of middle-school students, were used. Youth were initially assessed in 6th and 7th grade and followed-up 16 months later. Self-reports of frequency of energy drink, coffee, and alcohol consumption, as well as sensation-seeking, perceived peer and best friend alcohol use, alcohol expectancies, and parental monitoring, were used. Results indicated that both energy drink and coffee consumption predicted later alcohol consumption, even after adjusting for other risk factors for alcohol consumption. Parental monitoring was a significant moderator of this link, such that youth who consumed energy drinks and reported low parental monitoring were particularly at risk for later alcohol consumption. These findings indicate that the link between earlier caffeine consumption and later alcohol consumption is not simply due to the co-occurrence of caffeine consumption with other risk factors for alcohol use. In addition, risk associated with early energy drink consumption appears to be particularly pronounced for youth in families characterized by low parental monitoring.  相似文献   

17.
Background: Scientists have established that social networks influence adolescents' substance use behavior, an influence that varies by gender. However, the role of gender in this mechanism of influence remains poorly understood. Particularly, the role an adolescent's gender, alongside the gender composition of his/her network, plays in facilitating or constraining alcohol use is still unclear. Objectives: This study examined the associations among the gender composition of adolescents' networks, select network characteristics, intrapersonal and interpersonal factors, and alcohol use among a sample of adolescents in the United States. Methods: We assessed cross-sectional data from a 2010 study of 1,523 high school students from a school district in Los Angeles. Analyses of adolescents' network characteristics were conducted using UCINET 6; and logistic regression analyses testing the associations between gender composition of the network and alcohol use were conducted using SPSS 20. Results: Our results indicate that the gender composition of adolescents' networks in our sample is associated with alcohol use. Adolescents in predominantly female or predominantly male friendship networks were less likely to report alcohol use compared to adolescents in an equal/balanced network. In addition, depending upon the context/type of network, intrapersonal and interpersonal factors varied in their association with alcohol use. Conclusions/Importance: Based on these findings, we make several recommendations for the future research. We call for researchers to further examine gender as a risk factor for alcohol abuse, particularly within the complex interplay between gender and network contexts.  相似文献   

18.
An experiment was conducted to examine the effects of caffeine and noise on mood, mental performance and cardiovascular function. One hundred and six young adults (mean age 21·2 years) took part in the study. Subjects were assigned to one of six groups formed by combining noise/quiet and drink (caffeinated coffee, decaffeinated coffee and fruit juice) conditions. Subjects were familiarized with the tasks and then completed a pre-drink baseline session (conducted in the quiet). Subjects were then given either caffeinated coffee (1·5 mg/kg caffeine), decaffeinated coffee or fruit juice. Following consumption of the drink subjects were re-tested 1 h later, either in noise (75 dBA conglomerate noise, consisting of speech, music and machinery noise) or in quiet. The subjects exposed to noise felt more anxious and showed an increase in blood pressure. Their performance of a cognitive vigilance task also declined over time. There were no significant main effects of caffeine, although simple reaction time was quickest in the caffeinated coffee group. Caffeine did not modify the effects of noise on mood, cardiovascular functioning or sustained attention. Indeed, the only interaction between drinks and noise was found in recall and recognition memory tasks, with the caffeine/noise group having better memory performance than the decaffeinated/noise subjects. Overall, the results show that low levels of caffeine do not increase the behavioural and physiological changes observed in a stressful situation. © 1997 John Wiley & Sons, Ltd.  相似文献   

19.
The following hypothesis has been tested: sensation seeking, A-state and A-trait, and depressive mood should positively affect adolescent substance use. The personality variables and alcohol and drug use were assessed among 1,900 Israel adolescents, 14 to 19 years old. The major findings were as follows: (a) Sensation seeking and availability significantly affected the “ever” and “current” substance use among adolescents. On the other hand, contrary to our hypothesis, neither A-trait nor depressive mood significantly affected substance use. (b) A-State affected the use of alcoholic beverages and nonprescribed medications. (c) The data emphasized the significant role of availability of drugs in the understanding of adolescent' substance use. The implications of these findings for interventions among adolescents are discussed.  相似文献   

20.
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