Background: Caffeine acts as an anorexic agent, increases energy expenditures, and decreases total body fat mass, and could be detrimental to people living with HIV (PLWH). The objective of this study was to explore the relationship between caffeine consumption, body composition measures (fat mass, body mass index [BMI], and lean body mass [LBM]), nutrient intakes, CD4 counts, and HIV viral load in PLWH. Methods: A convenience sample of 130 PLWH was recruited and followed for 3 months. Caffeine intake, body composition measures, and nutrient intakes were collected using Modified Caffeine Consumption Questionnaire, bioimpedance analyses, and 24-hour dietary recalls. Linear regressions were used to analyze the baseline data for relationships between these variables. Linear mixed models (LMMs) were used to determine the overtime changes. Results: In baseline, linear regression analysis, higher caffeine consumption was associated with lower fat mass (β = -0.994, p = 0.042). However, BMI and LBM did not show any significant association with caffeine intake. LMM analysis showed that the association between caffeine intake and fat mass strengthened overtime (β = -1.987, p = 0.035). Baseline linear regression analysis showed that higher caffeine intake was significantly associated with lower caloric intakes from fat (β = -1.902, p = 0.044) and lower total caloric intake (β = -1.643, p = 0.042). However, LMM analysis showed that these associations diminished and lost significance overtime. There were no associations between body composition measures, nutrient intakes, CD4 counts, and HIV viral load. Conclusions: Caffeine intake adversely affected dietary intakes of macronutrients and total fat mass. Therefore, caffeine, a known anorectic, should be regulated in PLWH.
A recent long-term prospective study has demonstrated that coffee consumption by patients with autosomal dominant polycystic kidney disease (ADPKD) does not have a detrimental effect on kidney size or estimated glomerular filtration rate. We suggest that caffeine may, however, have a hypertensive effect in some ADPKD patients. Further research is needed before we can definitively state that caffeinated coffee consumption is harmless in ADPKD patients.
Background: This study was conducted to compare the pharmacokinetics of caffeine delivered using caffeinated chewing gum to that delivered using a marketed caffeinated beverage (instant coffee) in 16 healthy adult volunteers. Materials and Methods: This was a controlled open-label, randomized, two-period crossover study. Caffeinated chewing gum and a serving of instant coffee, each containing ∼50 mg caffeine, were administered with blood samples collected before and up to 24 hours after administration starts. Plasma caffeine levels were analyzed using validated liquid chromatography coupled with tandem mass spectrometry methodology. Results: There were no statistical differences between the two caffeine products in tmax (p = 0.3308) and ka (p = 0.3894). Although formulated at ∼50 mg caffeine each, mean dose released from chewing gum was ∼18% less than beverage. Dose-normalized area under the concentration-time curve (AUC)0-t, AUC0-∞, and Cmax was similar between products. Although the criteria were not set a priori and the study was not powered for concluding bioequivalence, the 90% confidence intervals fell within the bioequivalence limit of 80% to 125%. Conclusions: Existing scientific literature on caffeine, based mostly on data from caffeinated beverages, can be leveraged to support the safety of caffeine delivered by chewing gum and current maximum safe caffeine dose advice should be applicable irrespective of delivery method.
Background: Energy drink consumption and sleep problems are both associated with alcohol use among adolescents. In addition, caffeine consumption (including energy drinks) is associated with sleep problems. However, information about how these three constructs may interact is limited. The goal of this study was to examine potential interactions between energy drink consumption and sleep problems in the concurrent prediction of alcohol use among young adolescents. Coffee and soda consumption were also examined for comparison. Methods: Participants from the Camden Youth Development Study were included (n = 127; mean age = 13.1; 68% Hispanic, 29% African American) and questionnaire measures of frequency of caffeinated beverage consumption (energy drinks, coffee, and soda), sleep (initial insomnia, sleep disturbances, daytime fatigue, and sleep duration), and alcohol consumption were used. Regression analyses were conducted to examine interactions between caffeinated beverage consumption and sleep in the concurrent prediction of alcohol use. Results: Energy drink consumption interacted with initial insomnia and daytime fatigue to concurrently predict particularly frequent alcohol use among those with either of these sleep-related problems and energy drink consumption. The pattern of results for coffee consumption was similar for insomnia but reached only a trend level of significance. Results of analyses examining soda consumption were nonsignificant. Conclusions: Young adolescents who both consume energy drinks and experience initial insomnia and/or daytime fatigue are at particularly high risk for alcohol use. Coffee consumption appears to be associated with similar patterns. Longitudinal research is needed to explain the developmental pathways by which these associations emerge, as well as mediators and moderators of these associations.
Background: Medical residencies are highly demanding and stressful and have been associated with mental and emotional problems. Studies that evaluated this relationship in Italian psychiatry residents are scarce. In this study, we examined sleep quality and its association with perceived stress and caffeinated beverages consumption in Italian psychiatry residents. Methods: Seventy-two PGY1–5 psychiatry residents at two University Hospitals in Italy were asked to complete an anonymous questionnaire. The Pittsburgh Sleep Quality Index and Epworth Sleepiness Scale were used to determine the sleep quality and the level of daytime sleepiness (EDS). In addition, we investigated perceived stress and caffeinated drinks consumption (coffee, tea, soda, energy drinks). Results: Seventy psychiatry residents responded to the survey (97.2% response rate) (M = 34.3%, F = 65.7%; mean age = 30.5 ± 4.2 SD years). 44.3% had poor sleep quality and 15.7% had abnormal EDS. 64.3% reported significant perceived stress. Perceived stress score and coffee consumption were associated with greater likelihood of poor sleep quality. Conclusions: Psychiatry residents have high prevalence of poor sleep quality. Future longitudinal studies are needed to investigate causality and identify appropriate coping strategies and lifestyle changes aimed to improve mental health in psychiatry trainees.
Background: Caffeine is widely consumed in pregnancy and used therapeutically in preterm babies. Moderately high maternal consumption of caffeine is associated with detrimental neurological effects in the newborn, but there is insufficient information on its effects on the cerebellum in relationship to neurobehavior. We hypothesize that maternal consumption of caffeine will delay the structural and functional development of the cerebellum in offsprings. This study investigates the effect of perinatal maternal caffeine consumption in rats on neurobehavior and the structure of the external granular layer (EGL) in neonates. Materials and Methods: Pregnant rats received 50 or 100 mg/(kg/day) of caffeine (designated as CAF 50, CAF 100) by gavage throughout pregnancy and for 3 weeks during lactation. Controls received sterile water. The pups were tested for sensorimotor reflex development, motor coordination, and muscular strength. By serial sacrifice from days 19 to 21, cerebellar development was assessed by measuring the thickness of the EGL and the cellular density in the molecular layer. Results: Sensorimotor reflexes and motor coordination appeared earlier in CAF 50 rats than in CAF 100 and controls. Muscular strength was similar to controls in CAF 50, but reduced in CAF 100 rats. The EGL was consistently thicker and number of cells migrating through the molecular layer was higher in the CAF 100 group. Conclusions: High maternal caffeine consumption delayed the migration of EGL cells and thus retarded the development of the internal granular layer. We propose that the migration delay and neurobehavioral retardation are related.
Background: When caffeine is added to beverages, it increases beverage liking and the relative reinforcing value (RRV) of these beverages after repeated exposure. The purpose of this study was to test the hypothesis that a single acute exposure to caffeine increases liking and motivation to consume sugar-sweetened beverages (SSBs) relative to placebo. Methods: Participants were children ages 8-9 years (n = 36) and adolescents ages 15-17 years (n = 41) with an approximately equal number of boys and girls. A double-blind, placebo-controlled crossover study was conducted where participants sampled a SSB containing caffeine (1 and 2 mg/kg) on one visit and placebo (quinine 0.01 and 0.02 mg/kg) on a second visit day and then, on a third visit, played a computer game to earn points for the beverages and rated liking and taste sensations. They returned to the laboratory after a 1-week washout and had the alternate dose combination. Results: Acute exposure to the higher dose of caffeine increased the RRV of the SSB relative to placebo, but only when that dose was presented in the first week and only in female participants. The liking of the caffeine-containing SSB at the higher dose was lower than the placebo at all time points. Conclusions: These data suggest that a single exposure to a caffeinated SSB can impact its RRV and liking, but only under certain conditions and only in females. This supports previous work suggesting that caffeine can increase desire to consume SSB.
Background: Apnea of prematurity often occurs during and following caffeine therapy. We hypothesized that number of apnea events would be impacted by adjustments in caffeine therapy. Materials and Methods: An automated algorithm was used in all infants ≤32 weeks gestation admitted to a level IV Neonatal Intensive Care Unit from 2009 to 2014 to analyze chest impedance, electrocardiogram, and oxygen saturation data around the time of serum caffeine levels, caffeine boluses while on maintenance therapy, and caffeine discontinuation. Episodes of central apnea/bradycardia/desaturation (ABDs), and percent time with SpO2 <88% and <75% were measured. Results: ABDs were analyzed in 302 preterm infants (mean gestational age 27.6 weeks) around the time of 485 serum caffeine levels, 90 caffeine boluses, and 273 episodes of caffeine discontinuation. Higher serum caffeine levels were not associated with fewer ABDs or higher heart rate. For caffeine boluses given due to clinically recognized spells, hypoxemia and algorithm-detected ABDs decreased day 1-2 after the bolus compared to the day before and day of the bolus (mean 4.4 events/day after vs. 6.6 before, p = 0.004). After caffeine discontinuation, there was no change in hypoxemia and a small increase in ABDs (2 events/day 3-5 days after discontinuation vs. 1 event/day before and >5 days after, p < 0.01). This increase in ABDs occurred irrespective of gestational age, respiratory support, or postmenstrual age at the time caffeine was stopped. Conclusions: In this retrospective analysis, caffeine boluses and caffeine discontinuation were associated with a small change in the number of ABD events in preterm infants.
Many people avidly consume foods and drinks containing caffeine, despite its bitter taste. Here, we review what is known about caffeine as a bitter taste stimulus. Topics include caffeine's action on the canonical bitter taste receptor pathway and caffeine's action on noncanonical receptor-dependent and -independent pathways in taste cells. Two conclusions are that (1) caffeine is a poor prototypical bitter taste stimulus because it acts on bitter taste receptor-independent pathways, and (2) caffeinated products most likely stimulate "taste" receptors in nongustatory cells. This review is relevant for taste researchers, manufacturers of caffeinated products, and caffeine consumers.
Journal of Caffeine ResearchVol. 7, No. 3 Letter to the EditorRe: Effects of Caffeine on Heart Rate Variability in Boys by Turley et al. (J Caffeine Res 2017;7:71–77)Linda WassonLinda WassonSearch for more papers by this authorPublished Online:1 Sep 2017https://doi.org/10.1089/jcr.2017.0019AboutSectionsView articleView Full TextPDF/EPUB Permissions & CitationsPermissionsDownload CitationsTrack CitationsAdd to favorites Back To Publication ShareShare onFacebookTwitterLinked InRedditEmail View article"Re: Effects of Caffeine on Heart Rate Variability in Boys by Turley et al. (J Caffeine Res 2017;7:71–77)." Journal of Caffeine Research, 7(3), pp. 120–121FiguresReferencesRelatedDetails Volume 7Issue 3Sep 2017 InformationCopyright 2017, Mary Ann Liebert, Inc.To cite this article:Linda Wasson.Re: Effects of Caffeine on Heart Rate Variability in Boys by Turley et al. (J Caffeine Res 2017;7:71–77).Journal of Caffeine Research.Sep 2017.120-121.http://doi.org/10.1089/jcr.2017.0019Published in Volume: 7 Issue 3: September 1, 2017Online Ahead of Print:August 3, 2017PDF download
Pharmacokinetic and pharmacodynamic properties of caffeine as the most and widely consumed beverage in the globe were examined. Forty-three articles published between 1980 and 2016 were selected with a list of keywords that represent the most relevant pharmacokinetic and pharmacodynamic properties of caffeine. Findings show that the oral route is the most common route of administration of caffeine. The complete caffeine absorption takes place in the small intestine and it needs around 45 minutes to get 99% bioavailability with no significant first pass effect of caffeine. Caffeine absorption rate constant K01 is around 0.33 minute−1, volume of distribution is ranging between 0.5 and 0.75 L/kg, plasma-protein binding about 10–30%, half-life is around 4 hours, clearance is ranging between 1 and 3 mg/kg/min, and elimination rate constant is ranging between 0.09 and 0.33 hour−1. Caffeine elimination takes place by first-order kinetics and is effectively explained by a one-compartment open model system. Ninety-five percent of the caffeine primary metabolism is done in the liver by CYP1A2, and 3% or less is excreted unchanged in urine. Caffeine is metabolized through phase I oxidation reactions mainly to paraxanthine, theobromine, and theophylline followed by phase II conjugation. 1-Methylxanthine, 1-methyluric acid, 5-acetylamino-6-formylamino-3-methyluracil, and 1,7-dimethyluric acid are the main caffeine metabolites in the urine. Caffeine fatal dose ranges between 5 and 10 g/day.
Background: Caffeine has come to play a part in the day-to-day routine of most New Zealanders. Despite dynamic market growth of caffeinated foods and beverages, targeting adolescents and young adults, there is a lack of information on dietary exposure and current consumption patterns. Excess caffeine results in overstimulation of the central nervous system, and adverse caffeine-related health incidents have escalated in New Zealand over the last two decades. Factors that influence the consumption of caffeinated foods and beverages among adolescents and adults are unknown. The aim of this study was to undertake an in-depth exploration to understand factors that influence the consumption of caffeinated products among young New Zealanders. These data will inform the development of a caffeine consumption habit questionnaire to examine caffeine intakes among New Zealand adults and to determine subgroups at risk. Method: Seven focus groups with young adults in community settings (n = 43) were conducted to investigate cultural perspectives and diverse views and to provide a collective perspective of caffeinated product influences. A guide for planning the question route facilitated discussion and search for explanation and meaning. Focus groups were audio-recorded, transcribed, and text coded by inductive analysis using the thematic framework approach. Results: Four themes were identified that influenced the intake of caffeinated products among the focus group participants: the social and cultural context; environmental conditions; physical, psychological, and emotional expectations, and individual knowledge and perceptions. Conclusions: A complex interplay of factors influences caffeinated product consumption with interactions at the social, cultural, environmental, psychological, and physiological levels.
The relationship between caffeine use and risky behaviors was studied because of unavailable data in Nigeria. A sample of 465 randomly selected secondary school students completed questionnaires that assessed sociodemographic, personality traits, seven risky behaviors (sexual intercourse, suicide attempt, bullying, physical fighting, alcohol, cigarette, and marijuana use), and caffeine use. Analysis showed that 106 students (22.8%) consumed caffeine in the past 30 days. Current caffeine use was significantly associated with current alcohol use (adjusted odds ratio = 6.78; 95% confidence interval: 3.61–12.75) after adjusting for gender, age, personality traits, and other risky behaviors (p < 0.05). Further exploration is recommended to understand this association.
Background: We examined the effects of ingesting two preworkout supplements (PWSs) on selective attention and response inhibition, perceived exercise readiness (herein, readiness), and exercise performance-related parameters. Methods: Resistance-trained participants (N = 19) were randomized to a double-blind, crossover (7-day washout) placebo (PLA)-controlled study supplementing with (1) PLA; (2) PWS [beta-alanine (3.2 g), arginine alpha ketoglutarate (2.0 g), creatine nitrate (2.0 g), ascorbic acid (500 mg), N-acetyl tyrosine (300 mg), caffeine (300 mg), tetramethyluric acid (10 mg), Mucuna pruriens extract standardized for 15% l-Dopa (1.0 g), theacrine (10 mg), pyridoxal 5-phosphate (1.48 mg), folic acid (0.50 mg), and methylcobalamin (1.8 mg)]; and (3) PWS150 at ∼150% the PWS dose. Primary outcomes were Stroop test responses for congruent, incongruent, and interference tasks. Secondary outcomes were readiness and exercise performance (bench and leg press/Wingate). Data were analyzed by general linear models and presented as mean (standard deviation) or mean change [95% confidence interval, CI]. Results: Significant improvements in Stroop word testing were observed for PWS (6.57, 95% CI [1.36–11.8]) and PWS150 (11.5, 95% CI [6.26–16.6]), but not PLA (1.31, 95% CI [−3.89 to 6.52]). Significant changes in Stroop color testing were observed for PWS150 (8.1, 95% CI [4.52–11.6]) and PLA (4.47, 95% CI [0.89–8.05]), but not PWS (2.31, 95% CI [−1.26 to 5.89]). Similar results were observed for word–color. When all domains were summed, PWS150 (27.42 counts, 95% CI [16.08–38.76]) and PWS (12.26 counts, 95% CI [0.92–23.60]) showed significant improvements, but not PLA (11.26 counts, 95% CI [−0.077 to 22.60]). No significant changes in readiness, exercise performance, or adverse changes were otherwise observed. Conclusion: Consistent improvements in selective attention and response inhibition were observed with PWS150, but not readiness or exercise performance.
Objective: The study sought to measure the effects of caffeinated and decaffeinated coffee on affective mood, sleep, and health-related quality of life (HRQL). Methods: Forty-nine healthy participants between the ages of 18 and 45 took part in a randomized, double-blind, longitudinal study with decaffeinated coffee as the control. The participants began with a 5-day washout period, followed by a 5-day treatment phase, and concluded with a 5-day washout phase. Data were analyzed with repeated-measures analysis of covariance and ordinary least-squares mediational analysis. Results: The caffeinated coffee treatment group showed significant direct effects on sleep, anxiety, and stress-based domains of HRQL. In addition, mediational analysis showed that the more global domains of HRQL were affected indirectly through reduced sleep quality/quantity and through increases in anxiety. No significant changes were noted in the decaffeinated treatment group. Conclusions: Given the strong effect of caffeine on sleep and anxiety, as well as the indirect effect on HRQL in this study, it might be beneficial for individuals with stress responsive illnesses to refrain from high doses of caffeine. Further studies should examine the effects of caffeine in individuals with various stress-related illnesses. The results of caffeine on depression are contrary to previous studies, and further evaluations should examine variations of effects based on dosages and different populations (major depression diagnoses as well as healthy populations).
Background: Physical activity and caffeine consumption induce adaptations to the cardiovascular system, which can change basal and postcaffeine blood pressure (BP) and heart rate (HR) parameters. We hypothesized that physical activity would attenuate the pressor effects of acute caffeine ingestion regardless of caffeine consumption level. Methods: We evaluated the influence of regular physical activity and chronic caffeine consumption on basal and post-caffeine ingestion BP and HR. Sixty subjects (19–50 years old) participated in an interventional study. To evaluate the influence of regular physical activity and caffeine consumption, the participants were divided into four groups: sedentary nonhabitual caffeine consumers (S), sedentary habitual heavy caffeine consumers (SC), physically active nonhabitual caffeine consumers (A), and physically active habitual heavy caffeine consumers (AC). All groups had BP and HR assessed before (basal) and one hour after (post) caffeine ingestion (6 mg.kg−1 of body mass). Results: We found that group A had an increased systolic blood pressure (SBP) from 119.2 ± 11.3 to 124.2 ± 14.3 mmHg after acute caffeine ingestion. Lack of regular physical activity was associated with a significant increase in diastolic BP after caffeine ingestion (group S; 69.1 ± 7.7 vs. 73.8 ± 8.3 and group SC; 71.6 ± 9.5 vs. 75.3 ± 8.4). Group AC showed lower basal DBP than group SC (64.61 ± 8.1 and 71.5 ± 7.8 mmHg, respectively). Conclusion: Acute caffeine ingestion increases the SBP in physically active nonhabitual caffeine consumers.
Background: Experimental studies suggest that caffeine benefits cognitive function, including cognitive control processes such as response inhibition. However, recent cross-sectional studies purport that caffeine is, alternatively, associated with reduced response inhibition and associated concepts such as increased impulsivity, risk-taking, and aggression. However, such correlational designs, by definition, cannot conclude causal relationships. Thus, the present research employed a quasi-experimental design to explore whether caffeine influences response inhibition, impulsivity, risk-taking, and aggression in both high and low habitual caffeine consumers. Methods: Forty-one participants, including 15 high habitual caffeine consumers (caffeine intake >300 mg/day) and 26 low habitual caffeine consumers (caffeine intake <100 mg/day), consumed 0 mg, 100 mg, 200 mg, 400 mg, and their normal caffeine on each of five separate mornings. They completed trait measures of aggression, impulsivity, and anger, as well as cognitive tasks probing response inhibition, impulsivity, risk-taking, and aggression. Results: High habitual caffeine consumers reported greater trait motor impulsivity, that is, acting before carefully deliberating, compared with low habitual consumers. Acute caffeine intake enhanced nonaggressive responding to monetary rewards. However, acute caffeine intake did not influence response inhibition or impulsive, risky, or aggressive behavior in high or low habitual caffeine consumers. Conclusions: Thus, while habitual caffeine consumption was associated with greater impulsive behavior, acute caffeine consumption showed no evidence of influencing impulsivity, risk-taking, or aggression.
Background: This study aimed to examine the association between caffeine intake and postpartum depression in a group of Iranian women. Methods: This population-based cross-sectional study was performed on a representative sample of 360 women attending healthcare centers in Ardabil, Iran. Dietary intakes were assessed using a validated 106-item dish-based semiquantitative food frequency questionnaire. Caffeine intake was calculated through considering caffeine from all foods and beverages. The Edinburgh Postnatal Depression Scale was used to examine postpartum depression. Women with a score of 13 or more were considered as depressed. Results: Point prevalence of postpartum depression was 34.8 per 100 subjects. After controlling for potential confounders, we observed a significant association between caffeine intake and postpartum depression, controlling for some possible confounding variables (odds ratios [ORs] and corresponding 95% confidence interval [CI] for quartiles 1, 3, and 4 of caffeine intake were 1.8 [.9–3.6], 1.2 [.63–2.4], and 2.1 [1.1–4.1]), respectively. Furthermore, tea consumption was not related to the odds of postpartum depression (ORs and corresponding 95% CI for quartiles 1, 3, and 4 of tea intake were 1.1 [.59–2.2], 1.1 [.6–2.1], and 1.2 [.63–2.3]), respectively. The second quartile was considered as the reference group. Conclusion: No significant association was observed between caffeine or tea intake and odds of postpartum depression except for last quartile of caffeine in an adjusted model. Further investigations are needed to determine whether usual caffeine consumption can contribute to the risk of postpartum depression.
Background: Despite human exposition to environmental agents such as cadmium (Cd) and use of recreational beverages such as caffeine (Caf), it lacks investigations about their interactions on the central nervous system. This work investigates the effects of Cd+Caf intake on aggression behavior. Methods: Adult male Wistar rats received during 4 weeks: water (Ct), Cd solution-50 ppm, and Caf solution-5 ppm. At the end of the treatments, aggression behavior was evaluated using resident–intruder paradigm, and blood and brain were collected for measurement of Cd concentration. Results: No differences were observed between groups in water and food intake, and in animal weight gain. Cd levels increased in blood and in brain of animals exposed to Cd and Cd+Caf. Animals exposed to Cd and Caf alone showed no alterations in aggression behavior, while when together showed a significant increase of aggression behavior indicating clearly an effect of interaction due to coexposure. Conclusion: The interaction here observed is very worrying and major consequences of this type of coexposure should receive new toxicological considerations.
Rationale: Epidemiological research is yet to ascertain if caffeine consumption contributes to the development of cardiovascular disease. Consequently, there is a need for further experimental research to investigate the etiology of caffeine's effects on the cardiovascular system. Objectives: To examine the relationship between autonomic regulatory capacity and the cardiovascular response to caffeine ingestion. Methods: A block-randomized, double-blind, placebo-controlled, crossover experiment investigated the cardiovascular responses of 20 participants (n = 10 males) to acute caffeine ingestion. In a novel approach within caffeine research, the underlying autonomic regulatory capacity of the participants was indexed by measuring resting heart rate variability (HRV) and used to guide the analyses of the cardiovascular responses. Results: Results indicated that at rest, caffeine exerted a significant increase on the blood pressure of participants with higher, but not lower, resting HRV. Placebo elicited no cardiovascular differences. This suggests that individuals with greater autonomic regulatory capacity are more responsive to the pharmacological effects of caffeine. Conclusion: Overall, the findings suggest that autonomic regulatory capacity may represent an interindividual difference that predicts differential cardiovascular responsivity to caffeine ingestion. Further research is required to replicate this novel finding.
