A combination of caffeine and taurine has no effect on short term memory but induces changes in heart rate and mean arterial blood pressure

Acute effects of energy drink consumption on cardiovascular parameters in healthy adults: a systematic review and meta-analysis of randomized clinical trials

CONTEXT

Energy drinks (EDs) are beverages that contain ingredients that may pose a risk to consumers' cardiovascular health. But current evidence is conflicting and warrants further investigation.

OBJECTIVE

A systematic review and meta-analysis was conducted on studies that examined the acute effects of ED consumption on systolic blood pressure (SBP), diastolic blood pressure (DBP), resting heart rate, cardiac output (CO), endothelial function, and QT/QTc interval in healthy adults.

DATA SOURCES

The databases PubMed, EMBASE, Cochrane, LILACS, Web of Science, SportDiscus, and the gray literature were searched to identify randomized controlled trials (RCTs).

DATA EXTRACTION

Two independent evaluators screened 2014 studies and extracted relevant data from those selected for the analysis. A risk of bias assessment was also performed with the RoB 2 tool and a strength of evidence assessment was performed with the Grading of Recommendations Assessment, Development and Evaluation (GRADE).

DATA ANALYSIS

A total of 17 RCTs were included in the meta-analysis. With regard to risk of bias, 11 studies were rated as having "some concerns" and 6 as "high risk of bias." The consumption of EDs increased SBP, DBP, and CO in different time frames. More pronounced effects were seen on SBP at 60-80 minutes (4.71 mmHg; 95% CI: 2.97-6.45; GRADE: moderate), DBP at 120 minutes (4.51 mmHg; 95% CI: 2.60-6.42; GRADE: low), and CO at 30-40 minutes after consumption (0.43 L; 95% CI: 0.08-0.77; GRADE: very low). The effects of ED consumption on resting heart rate and QT/QTc interval were not significant (P ≤ 0.05). The assessment of endothelial function effects was not performed due to the absence of any RCTs meeting the inclusion criteria.

CONCLUSIONS

Acute consumption of EDs increases SBP, DBP, and CO in healthy adults. However, no alterations were observed in other cardiovascular parameters. The results should be interpreted with caution due to the limited number of studies included in the analysis.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registration no. CRD42022295335.

Knowledge, attitude, and perception of energy drinks consumption among university students in Jordan

Energy drinks gained popularity after the launch of Red Bull in 1997. Different brands are now available and young adults mainly consume these drinks. This study assesses the knowledge, attitude, and perception of energy drink consumption among university students in Jordan. A validated online survey was used to collect the required data, extracted from Google Forms into an Excel spreadsheet and statistically analysed using Statistical Package for Social Sciences version 24.0. A nationally representative sample of university students with a mean age of 22⋅2 ± 3⋅9 years (n 749) was obtained. The participating students demonstrated a neutral level of knowledge about energy drinks, as the mean score of knowledge = 7⋅1 ± 2⋅2 (out of 12), with 66 % (n 498) of them having consumed energy drinks and experienced their effects. Generally, the study's participants demonstrated a neutral attitude towards energy drinks and 70⋅5 % (n 528) acknowledged that energy drinks increase activity, but more than 70 % of them believed that energy drinks have harmful side effects. It was found that there is a significant (P-value <0⋅5) positive correlation between knowledge score and female gender, studying a medical major, and monthly income. The main reasons for consuming energy drinks were reported to be: to stay awake for longer, help study, and become more energetic. There is a need for more structured awareness campaigns to warn students about the possible side effects of these products in order to reduce the consumption and popularity of these drinks among students.

Revealing the Acute Effects of Dietary Components on Mood and Cognition: The Role of Autonomic Nervous System Responses

A growing body of literature suggests dietary components can support mood and cognitive function through the impact of their bioactive or sensorial properties on neural pathways. Of interest, objective measures of the autonomic nervous system-such as those regulating bodily functions related to heartbeat and sweating-can be used to assess the acute effects of dietary components on mood and cognitive function. Technological advancements in the development of portable and wearable devices have made it possible to collect autonomic responses in real-world settings, creating an opportunity to study how the intake of dietary components impacts mood and cognitive function at an individual level, day-to-day. In this paper, we aimed to review the use of autonomic nervous system responses such as heart rate or skin galvanic response to investigate the acute effects of dietary components on mood and cognitive performance in healthy adult populations. In addition to examining the existing methodologies, we also propose new state-of-the-art techniques that use autonomic nervous system responses to detect changes in proxy patterns for the automatic detection of stress, alertness, and cognitive performance. These methodologies have potential applications for home-based nutrition interventions and personalized nutrition, enabling individuals to recognize the specific dietary components that impact their mental and cognitive health and tailor their nutrition accordingly.

Consumption patterns of energy drinks in university students: A systematic review and meta-analysis

OBJECTIVES

Energy drink (ED) use is promoted to stimulate mental and/or physical activity, and their popularity has increased over the years, especially among young people. However, the use of EDs is often improper, and can induce adverse effects for human health. The purpose of this systematic review and meta-analysis was to analyze the literature to characterize the prevalence of ED consumption and motivations for use among undergraduate students. Furthermore, adverse effects and health-related behaviors associated with ED consumption were explored.

METHODS

This systematic review was carried out according to the Preferred Reporting Items for Systematic Review and Meta-Analysis guidelines, and the PubMed, Scopus, and Web of Science databases were used for data research.

RESULTS

A total of 71 articles published between 2007 and 2021 met the inclusion criteria and were included in the review. The estimated overall prevalence of ED consumption was 42.9% in undergraduate students (95% confidence interval, 42.5%-43.3%), with significant heterogeneity among studies (Q test: P < 0.001; I² = 99.4%). The main reasons for use were engagement in study, projects or examinations, stay awake or alert, and physical activity/sport engagement. Sleep disturbance and increased heart rate or blood pressure were the most commonly reported adverse effects. ED consumption was frequently associated with alcohol use and smoking.

CONCLUSIONS

These findings suggest that the inappropriate use of EDs and related unhealthy behaviors should be identified early, and addressed through effective educational interventions.<END ABSTRACT>.

Energy drinks and alcohol in a binge drinking protocol in Wistar rats: Male and female behavioral and reproductive effects

The consumption of energy drinks is common among adolescents and young adults. The possible effects (mainly behavioral and reproductive) of ingestion in this population remain unknown. For this reason, this study aimed to evaluate the behavioral and reproductive effects of energy drinks and their main constituents (caffeine and taurine), as well as their combinations with alcohol, via a binge drinking protocol in male and female Wistar rats during puberty. In this study, 100 male and 100 female rats were treated with a binge drinking protocol 3 days a week over 4 weeks from postnatal day (PND) 28 to PND 60, which included 10 mL/kg by oral gavage of distilled water, energy drink, caffeine (3.2 mg/kg), taurine (40 mg/kg), and their combinations with alcohol (2 g/kg). The animals were evaluated by behavioral tests from PND 56 to PND 60 (open field, plus maze and object recognition) and reproductive parameters (estrous cycle regularity, weight of sexual organs, oocyte quality, spermatid and sperm count, sperm morphology and testosterone level). Locomotor activity was increased in females in the groups combined with alcohol (except alcohol + caffeine) and in the caffeine group. Long-term memory was increased in males in the caffeine and taurine groups even when combined with alcohol. The combination of energy drinks and alcohol did not have significant effects on the reproductive parameters of either sex of rats during puberty. We concluded that energy drinks (and their main constituents) and alcohol combinations did not cause alterations in reproductive profiles, and locomotor activity and long-term memory were increased in females and males, respectively.

Caffeinated energy drinks in the Canadian context: health risk assessment with a focus on cardiovascular effects

In Canada, caffeinated energy drinks (CEDs) currently sold under Temporary Marketing Authorizations must meet strict eligibility criteria. These criteria, which include compositional and labelling requirements, were developed based on the outcome of a health risk assessment conducted by Health Canada (HC) in 2013. HC updated its assessment by reviewing new information with the focus on potential cardiovascular effects associated with the consumption of CEDs available for sale in Canada. Due to limited data on CED consumption among Canadians to derive accurate exposure information, the composition of a typical CED was characterized to assess the potential effects of single ingredients and synergistic interactions between ingredients on the cardiovascular system. Surveillance data on potential adverse effects related to CED consumption was also analyzed. After extensive review, HC's updated assessment confirms the current risk management approach for CEDs is health protective for Canadian consumers, including the potential for cardiovascular effects. The available evidence supports that moderate consumption (up to 500 mL per day) of a typical CED authorized for sale in Canada is safe for the general population of healthy adults and adolescents. It also re-confirms that vulnerable sub-populations (i.e., children, pregnant and/or breastfeeding women, and caffeine-sensitive individuals) should not consume CEDs. Novelty: Consumption up to 500 mL per day of a typical CED is not associated with an increased risk of cardiovascular effects. Children, pregnant and/or breastfeeding women, and caffeine-sensitive individuals should not consume CEDs.

Energy Drink Doses of Caffeine and Taurine Have a Null or Negative Effect on Sprint Performance

Jeffries, O, Hill, J, Patterson, SD, and Waldron, M. Energy drink doses of caffeine and taurine have a null or negative effect on sprint performance. J Strength Cond Res 34(12): 3475-3481, 2020-This study investigated the effects of caffeine and taurine coingestion on repeat-sprint cycling performance and associated physiological and perceptual responses. In a double-blind, cross-over, repeated measures study, 11 male subjects (age 21 ± 2 years; stature 178 ± 7 cm; body mass 80 ± 13 kg) completed 10 × 6-second sprints on a cycle ergometer, each separated by 24 seconds, one hour after ingesting: caffeine (80 mg) and taurine (1 g), equivalent to the amount observed in popular commercial energy drinks, or placebo (maltodextrin ∼1 g) in a gelatine capsule. Performance was measured on a cycle ergometer, whereas blood lactate concentration (B[la]), rating of perceived exertion (RPE), and heart rate (HR) were measured at baseline (pre-exercise) and after sprints 5 and 10. Magnitude-based inferences revealed likely, trivial differences in peak power and unclear, trivial intersprint fatigue index after ingestion of the caffeine and taurine supplement. Intrasprint fatigue was greater in the caffeine and taurine condition at sprint 10 (likely, small) and possibly smaller in sprints 6-9. The caffeine and taurine supplement had a likely large effect on HR at baseline (effect size = 0.94) and increases in B[la] after sprints 5 (likely small) and 10 (possibly small). There was no effect of the supplement on RPE (unclear, trivial). Administration of caffeine and taurine at doses equivalent to commercial energy drinks did not improve repeat-sprint cycling performance and seemed to induce greater fatigue within selected sprints, particularly at the end of the trial. This undesirable performance effect occurs in parallel with increased HR and glycolytic metabolic bi-products.

A Pilot Study on the Effect of an Energy Drink on Interoception in High vs. Low Anxiety Sensitivity Individuals

Abstract. Background: The market for energy drinks has grown quickly over the past 20 years. While the physiological and psychological effects of different ingredients have been studied, the influence of energy drinks on interoceptive processes is unclear. Anxiety has been associated with amplified interoceptive functioning, suggesting potentially exaggerated reactions to energy drinks. Aims: Investigate the effect of energy drink consumption and anxiety sensitivity (AS) as well as their possible interactions on cardiorespiratory dimensions of interoception. Method: Thirty-nine healthy students consumed an energy drink via a placebo-controlled, counterbalanced, crossover design. Cardiac and respiratory interoceptive accuracy (IAcc), interoceptive sensibility (IS), and interoceptive evaluation (IE) were assessed. Heartbeat-evoked potentials (HEPs) were analyzed to evaluate neural processing of the heartbeat. Results: Consumption of one energy drink did not influence IAcc, IS, or IE. However, high AS subjects reported reduced interoceptive confidence after energy drink intake. While HEP amplitudes did not differ depending on the type of drink, high AS subjects showed reduced HEPs overall compared to low AS subjects. Heart rate was significantly lower following energy drink consumption as compared to the placebo condition. Limitations: The sample size was small, energy dosages low, and physiological parameters should be assessed in more detail. Conclusion: Energy drink consumption was associated with an interoceptive bias in high AS individuals suggesting possible interaction effects between changes in physical state, interoception, and anxiety.

Red Bull Increases Heart Rate at Near Sea Level and Pulmonary Shunt Fraction at High Altitude in a Porcine Model

Red Bull energy drink is popular among athletes, students and drivers for stimulating effects or enhancing physical performance. In previous work, Red Bull has been shown to exert manifold cardiovascular effects at rest and during exercise. Red Bull with caffeine as the main ingredient increases blood pressure in resting individuals, probably due to an increased release of (nor)-epinephrine. Red Bull has been shown to alter heart rate or leaving it unchanged. Little is known about possible effects of caffeinated energy drinks on pulmonary ventilation/perfusion distribution at sea level or at altitude. Here, we hypothesized a possible alteration of pulmonary blood flow in ambient air and in hypoxia after Red Bull consumption. We subjected eight anesthetized piglets in normoxia (FiO₂ = 0.21) and in hypoxia (FiO₂ = 0.13), respectively, to 10 mL/kg Red Bull ingestion. Another eight animals served as controls receiving an equivalent amount of saline. In addition to cardiovascular data, ventilation/perfusion distribution of the lung was assessed by using the multiple inert gas elimination technique (MIGET). Heart rate increased in normoxic conditions but was not different from controls in acute short-term hypoxia after oral Red Bull ingestion in piglets. For the first time, we demonstrate an increased fraction of pulmonary shunt with unchanged distribution of pulmonary blood flow after Red Bull administration in acute short-term hypoxia. In summary, these findings do not oppose moderate consumption of caffeinated energy drinks even at altitude at rest and during exercise.

Anxiety-like behavior and whole-body cortisol responses to components of energy drinks in zebrafish (Danio rerio)

The current study investigated the independent and combined effects of caffeine and taurine on anxiety-like behavior and neuroendocrine responses in adult zebrafish (Danio rerio). Caffeine (1,3,7-trimethylpurine-2,6-dione), the world’s most commonly used psychoactive drug, acts as an adenosine receptor blocker and a mild central nervous system stimulant. However, excessive use of caffeine is associated with heightened anxiety levels. Taurine (2-aminoethanesulfonic acid), a semi-essential amino acid synthesized within the human brain, has been hypothesized to play a role in regulating anxiolytic behavior. Caffeine and taurine are two common additives in energy drinks and are often found in high concentrations in these beverages. However, few studies have investigated the interaction of these two chemicals with regards to anxiety measures. A suitable vertebrate to examine anxiety-like behavior and physiological stress responses is the zebrafish, which has shown promise due to substantial physiological and genetic homology with humans. Anxiety-like behavior in zebrafish can be determined by analyzing habituation to novelty when fish are placed into a novel tank and scototaxis (light avoidance) behavior in the light-dark test. Stress-related neuroendocrine responses can be measured in zebrafish by analyzing whole-body cortisol levels. The goal of this study was to determine if exposure to caffeine, taurine, or a combination of the two compounds altered anxiety-like behavior and whole-body cortisol levels in zebrafish relative to control. Zebrafish were individually exposed to either caffeine (100 mg/L), taurine (400 mg/L), or both for 15 min. Zebrafish in the control group were handled in the same manner but were only exposed to system tank water. After treatment, fish were transferred to the novel tank test or the light-dark test. Behavior was tracked for the first 6 min in the novel tank and 15 min in the light-tark test. Fifteen min after introduction to the behavioral task, fish were euthanized for the analysis of whole-body cortisol levels. The results demonstrate that caffeine treatment decreased the amount of exploration in the top of the novel tank and increased scototaxis behavior in the light-dark test, which supports the established anxiogenic effect of acute exposure to caffeine. Taurine alone did not alter basal levels of anxiety-like behavioral responses nor ameliorated the anxiogenic effects of caffeine on behavior when the two compounds were administered concurrently. None of the drug treatments altered basal levels of whole-body cortisol. The current results of this study suggest that, at least at this dose and time of exposure, taurine does not mitigate the anxiety-producing effects of caffeine when administered in combination, such as with energy drink consumption.

Energy Drinks Induce Acute Cardiovascular and Metabolic Changes Pointing to Potential Risks for Young Adults: A Randomized Controlled Trial

BACKGROUND

Case reports suggest a link between energy drinks (EDs) and adverse events, including deaths.

OBJECTIVES

We examined cardiovascular and metabolic effects of EDs and mixtures providing relevant ingredients of EDs compared to a similarly composed control product (CP) without these components.

METHODS

This randomized, crossover trial comprised 38 adults (19 women, mean BMI 23 kg/m2, mean age 22 y). We examined effects of a single administration of a commercial ED, the CP, and the CP supplemented with major ED-ingredients at the same concentrations as in the ED. The study products were administered at 2 volumes, 750 or 1000 mL.

RESULTS

Both volumes of the study products were acceptably tolerated with no dose-dependent effects on blood pressure (BP, primary outcome), heart rate, heart rate corrected duration of QT-segment in electrocardiography (QTc interval), and glucose metabolism. After ED consumption, 11% of the participants reported symptoms, in contrast to 0-3% caused by other study products. After 1 h, administration of an ED caused an increase in systolic BP (116.9 ± 10.4 to 120.7 ± 10.7 mmHg, mean ± SD, P < 0.01) and a QTc prolongation (393.3 ± 20.6 to 400.8 ± 24.1 ms, P < 0.01). Also caffeine, but not taurine or glucuronolactone, caused an increase in BP, but no QTc prolongation. The BP effects were most pronounced after 1 h and returned to normal after a few hours. All study products caused a decrease in serum glucose and an increase in insulin concentrations after 1 h compared to baseline values, corresponding to an elevation in the HOMA-IR (ED + 4.0, other products + 1.0-2.8, all P < 0.001).

CONCLUSION

A single high-volume intake of ED caused adverse changes in BP, QTc, and insulin sensitivity in young, healthy individuals. These effects of EDs cannot be easily attributed to the single components caffeine, taurine, or glucuronolactone. This trial was registered at clinicaltrials.gov as NCT01421979.

Perinatal exposure to energy drink induces oxidative damage in the liver, kidney and brain, and behavioral alterations in mice offspring

The worldwide consumption of energy drinks (EDs) has increased in recent years. EDs have several side effects and can be linked to liver injury, kidney damage and risk-seeking behavior. The impact of perinatal consumption of EDs on the newborns has not been previously investigated. In this study, we evaluated the effects of perinatal exposure to a caffeinated ED on the liver, kidney, brain, locomotor activity and anxiety in mice newborns. Pregnant mice received 2.5 or 5 ml ED by oral gavage from the first day of pregnancy until day 15 after birth. Perinatal exposure to the ED induced a significant increase in lipid peroxidation and declined antioxidant defenses in the liver, kidney, cerebrum, cerebellum and medulla oblongata of the newborns at days 21 and 35 after birth. ED induced several histological alterations, including vacuolations and lipid infiltration of hepatocytes, developing and degenerated glomeruli and dilated urinary spaces in the renal cortex, pyknosis and chromatolysis of the cerebral and medullary neurons, and degenerated and abnormal Purkinje cells in the cerebellum. In addition, ED increased the locomotion and induced anxiety-like behavior in mice newborns. In conclusion, perinatal exposure to EDs induces oxidative stress, tissue injury and behavioral alterations in the mice newborns. Therefore, the consumption of EDs during pregnancy and lactation has a negative impact on the newborns and should be treated as a significant health problem that warrants attention.

Exposure and perceptions of marketing for caffeinated energy drinks among young Canadians

OBJECTIVE

To examine exposure to energy drink marketing among youth and young adults, and test perceptions of energy drink advertisements (ads) regarding target audience age and promoting energy drink use during sports.

DESIGN

A between-group experiment randomly assigned respondents to view one of four energy drink ads (sport-themed or control) and assessed perceptions of the ad. Regression models examined marketing exposure and perceptions.

SETTING

Online survey (2014).

SUBJECTS

Canadians aged 12-24 years (n 2040) from a commercial panel.

RESULTS

Overall, 83 % reported ever seeing energy drink ads through at least one channel, including on television (60 %), posters/signs in stores (49 %) and online (44 %). Across experimental conditions, most respondents (70·1 %) thought the ad they viewed targeted people their age or younger, including 42·2 % of those aged 12-14 years. Two sport-themed ads were more likely to be perceived as targeting a younger audience (adjusted OR (95 % CI): 'X Games' 36·5 %, 4·16 (3·00, 5·77); 'snowboard' 19·2 %, 1·50 (1·06, 2·13)) v. control (13·3 %). Participants were more likely to believe an ad promoted energy drink use during sports if they viewed any sport-themed ad ('X Games' 69·9 %, 8·29 (6·24, 11·02); 'snowboard' 76·7 %, 11·85 (8·82, 15·92); 'gym' 66·8 %, 7·29 (5·52, 9·64)) v. control (22·0 %). Greater reported exposure to energy drink marketing was associated with perceiving study ads as promoting energy drink use during sports.

CONCLUSIONS

Energy drink marketing has a high reach among young people. Ads for energy drinks were perceived as targeting youth and promoting use during sports. Such ads may be perceived as making physical performance claims, counter to Canadian regulations.

The Effects of Caffeine, Taurine, or Caffeine-Taurine Coingestion on Repeat-Sprint Cycling Performance and Physiological Responses

Purpose: To investigate the effects of caffeine (C), taurine (T), caffeine and taurine coingestion (C +T), or placebo (P) on repeated Wingate cycling performance and associated physiological responses. Methods: Seven male team-sport players participated in a randomized, single-blind, crossover study, where they completed 3 Wingate tests, each separated by 2 min, an hour after ingesting: C (5 mg/kg body mass [BM]), T (50 mg/kg BM), C +T (5 mg/kg BM + 50 mg/kg BM), or P (5 mg/kg BM) in a gelatin capsule. Performance was measured on an ergometer, and blood lactate, perceived exertion, heart rate (HR), mean arterial pressure (MAP), and rate pressure product (RPP) were measured at rest (presupplement), baseline (1 h postsupplement), and during and after exercise. Results: Magnitude-based inferences revealed that all of the supplements increased (small to moderate, likely to very likely) mean peak power (MPP), peak power (PP), and mean power (MP) compared to P, with greater MPP, PP, and MP in T compared to C (small, possible). Intrasprint fatigue index (%FIIntra) was greater in T compared to P and C (moderate, likely), and %FIInter was lower in T compared to C (small, possible). C and C +T increased HR, MAP, and RPP compared to P and T at baseline (moderate to very large, likely to most likely); however, these only remained higher in C compared to all conditions in the final sprint. Conclusions: T elicited greater improvements in performance compared to P, C, or C +T while reducing the typical chronotropic and pressor effects of C.

Effects of caffeine intake prior to stress cardiac magnetic resonance perfusion imaging on regadenoson- versus adenosine-induced hyperemia as measured by T1 mapping

The antagonistic effects of caffeine on adenosine receptors are a possible cause of false-negative stress perfusion imaging. The purpose of this study was to determine the effects of coffee intake <4 h prior to stress perfusion cardiac magnetic resonance imaging (CMR) in regadenoson- versus adenosine-induced hyperemia as measured with T1-mapping. 98 consecutive patients with suspected coronary artery disease referred for either adenosine or regadenoson perfusion CMR were included in this analysis. Twenty-four patients reported coffee consumption <4 h before CMR (15 patients with adenosine, and 9 patients with regadenoson); 74 patients reported no coffee intake (50 patients with adenosine, and 24 patients with regadenoson). T1 mapping was performed using a modified look-locker inversion recovery sequence. T1 reactivity was determined by subtracting T1_rest from T1_stress. T1_rest, T1_stress, and T1 reactivity in patients referred for regadenoson perfusion CMR were not significantly different when comparing patients with <4 h coffee intake and patients who reported no coffee intake (976 ± 4 ms, 1019 ± 48 ms, and 4.4 ± 3.2% vs 971 ± 33 ms, 1023 ± 43 ms, and 5.4 ± 2.4%) (p = 0.70, 0.79, and 0.40), and similar to values in patients without coffee intake undergoing adenosine CMR. In patients with <4 h coffee intake, T1_stress, and T1 reactivity were significantly lower for adenosine (898 ± 51 ms, and −7.8 ± 5.0%) compared to regadenoson perfusion CMR (p < 0.001). Coffee intake <4 h prior to regadenoson perfusion CMR has no effect on stress-induced hyperemia as measured with T1 mapping.

Effects of Energy Drinks on Economy and Cardiovascular Measures

Peveler, WW, Sanders, GJ, Marczinski, CA, and Holmer, B. Effects of energy drinks on economy and cardiovascular measures. J Strength Cond Res 31(4): 882-887, 2017-The use of energy drinks among athletes has risen greatly. Caffeine and taurine are the 2 primary performance enhancing ingredients found in energy drinks. The number of emergency department visits involving energy drinks doubled over the past 5 years. Reviews of the health complications have highlighted adverse cardiovascular events. The literature reveals that caffeine is known to moderately increase blood pressure (BP) and heart rate (HR). The purpose of this study was to determine the effect of 3 different energy drinks on cardiovascular and performance measures. Fifteen recreational runners completed 5 trials. The first trial consisted of a graded exercise protocol. The 4 remaining trials consisted of 15-minute economy trials at a treadmill speed consistent with 70% of subject's V[Combining Dot Above]O2max. An hour before subjects ingested 1 of the 3 energy drinks or a placebo. HR, BP, V[Combining Dot Above]O2, and rating of perceived exertion (RPE) were recorded during the 15-minute trial. Mean values for dependent measures were compared using repeated-measures analysis of variance. Fifteen-minute systolic BP readings were significantly lower in the placebo trials (156.93 ± 15.50) in relation to the 3 energy drink trials (163.87 ± 13.30, 166.47 ± 13.71, and 165.00 ± 15.23). There were no significant differences in diastolic BP and HR. There were no significant differences found in V[Combining Dot Above]O2 or RPE measures. Ingestion of energy drinks demonstrated no change in V[Combining Dot Above]O2 or RPE during the economy trials. The findings show no performance benefits under the conditions of this study. However, there does appear to be a significant increase in systolic BP.

Energy Drinks and Their Impact on the Cardiovascular System: Potential Mechanisms

Globally, the popularity of energy drinks is steadily increasing. Scientific interest in their effects on cardiovascular and cerebrovascular systems in humans is also expanding and with it comes a growing number of case reports of adverse events associated with energy drinks. The vast majority of studies carried out in the general population report effects on blood pressure and heart rate. However, inconsistencies in the current literature render it difficult to draw firm conclusions with regard to the effects of energy drinks on cardiovascular and cerebrovascular variables. These inconsistencies are due, in part, to differences in methodologies, volume of drink ingested, and duration of postconsumption measurements, as well as subject variables during the test. Recent well-controlled, randomized crossover studies that used continuous beat-to-beat measurements provide evidence that cardiovascular responses to the ingestion of energy drinks are best explained by the actions of caffeine and sugar, with little influence from other ingredients. However, a role for other active constituents, such as taurine and glucuronolactone, cannot be ruled out. This article reviews the potentially adverse hemodynamic effects of energy drinks, particularly on blood pressure and heart rate, and discusses the mechanisms by which their active ingredients may interact to adversely affect the cardiovascular system. Research areas and gaps in the literature are discussed with particular reference to the use of energy drinks among high-risk individuals.

Energy drinks consumption in Italian adolescents: preliminary data of social, psychological and behavioral features

BACKGROUND

The aim of this study was to investigate the prevalence of energy drink (ED) consumption and the associations with social, psychological and behavioral features among an Italian adolescent sample.

METHODS

A cross-sectional prevalence study of 450 Italian adolescents attending middle school was conducted. The Italian versions of the European Food Safety Authority's adolescent Energy Drinks Questionnaire and of the Depression and Anxiety in Youth Scale (DAYS) were administered to evaluate ED use and its psychological correlates. Odds ratios (OR) with 95% confidence intervals (CI) were calculated using a logistic model to estimate the associations between ED consumption and socio-demographic characteristics, psychological factors and risky behaviors.

RESULTS

The prevalence of ED consumers was 57%, of whom 49% used alcohol mixed with ED. A total of 9% exhibited high chronic consumption, 31% average chronic consumption and 8% high acute consumption. Males were significantly more likely to use ED (OR=2.7, 95% CI: 1.8-4.0, P=0.00) and to engage in high acute consumption (OR=4.0, 95% CI: 1.1-13.8, P=0.03). Regular smoking was associated with ED use (OR=3.4, 95% CI: 1.2-9.1, P=0.02). No relationship was observed between ED use and depression (OR=1.6, 95% CI: 0.9-3.0, P=0.10) and anxiety (OR=0.8, 95% CI: 0.5-1.4, P=0.44), although those who were depressed with a suggestive but not statistically significant increased risk of acute ED use (OR=2.7, 95% CI: 1.0-7.4, P=0.06).

CONCLUSIONS

The prevalence of ED consumption among middle school Italian students was high and it was associated with another risky behavior, smoking, but not with anxiety or depression. About half of ED consumers used alcohol mixed with ED.

Evaluation of the Effects of Different Energy Drinks and Coffee on Endothelial Function

Endothelial function plays an important role in circulatory physiology. There has been differing reports on the effect of energy drink on endothelial function. We set out to evaluate the effect of 3 energy drinks and coffee on endothelial function. Endothelial function was evaluated in healthy volunteers using a device that uses digital peripheral arterial tonometry measuring endothelial function as the reactive hyperemia index (RHI). Six volunteers (25 ± 7 years) received energy drink in a random order at least 2 days apart. Drinks studied were 250 ml "Red Bull" containing 80 mg caffeine, 57 ml "5-hour Energy" containing 230 mg caffeine, and a can of 355 ml "NOS" energy drink containing 120 mg caffeine. Sixteen volunteers (25 ± 5 years) received a cup of 473 ml coffee containing 240 mg caffeine. Studies were performed before drink (baseline) at 1.5 and 4 hours after drink. Two of the energy drinks (Red Bull and 5-hour Energy) significantly improved endothelial function at 4 hours after drink, whereas 1 energy drink (NOS) and coffee did not change endothelial function significantly. RHI increased by 82 ± 129% (p = 0.028) and 63 ± 37% (p = 0.027) after 5-hour Energy and Red Bull, respectively. The RHI changed after NOS by 2 ± 30% (p = 1.000) and by 7 ± 30% (p = 1.000) after coffee. In conclusion, some energy drinks appear to significantly improve endothelial function. Caffeine does not appear to be the component responsible for these differences.

Resting heart rate on the decline: the Tromsø Study 1986-2007

BACKGROUND

We examined secular changes in resting heart rate (RHR) and their relationship with changes in other cardiovascular risk factors in adult men and women over a 22-year period.

METHODS

A single-centre population-based longitudinal study comprised 30,699 men and women aged 30-89 years who participated in at least one of the 1986, 1994, 2001 and 2007 surveys of the Tromsø Study, Tromsø, Norway.

RESULTS

During the study period, the age-adjusted means of RHR declined from 73.4 to 64.7 beats per minute (b.p.m.) in men, and from 78.3 to 66.4 b.p.m. in women. The decline was persistent from one survey to the next and was of similar size in both sexes and for all age groups and birth cohorts. RHR declined gradually over time for different levels of cardiovascular risk factors, and it declined more in those who moved from adverse to favourable values or categories of blood pressure, total and high-density lipoprotein cholesterol, triglycerides, body mass index, smoking and physical activity, and those who started to take blood pressure medication. The strongest predictors of individual decline in RHR were decrease in systolic blood pressure and triglycerides, increase in physical activity, taking blood pressure treatment and smoking cessation.

CONCLUSION

A considerable decline in RHR has occurred in Tromsø over the past two decades in men and women of all ages. The decline is partly related to changes in several cardiovascular risk factors, and reasons behind this need to be further elucidated. The findings suggest that new definitions of normal RHR may be needed.

Effect of energy drink and caffeinated beverage consumption on sleep, mood, and performance in children and adolescents

The increasing availability of highly caffeinated beverages, including energy drinks, in the United States has resulted in a rise in consumption by children and adolescents. In addition, there is mounting evidence that these products are often consumed by youth for their perceived fatigue-mitigating and mood- or performance-enhancing effects. Although such perceptions by children and adolescents about the potential consequences of caffeine consumption are highly likely to influence decision making regarding the use of such products, there is still a relative paucity of studies that focus on the effect of caffeinated beverages on sleep, mood, and performance in the pediatric population. This review summarizes the following aspects of this topic, as derived from the information currently available: 1) the perception, among youth, of caffeine's risks and benefits and the sources of information about caffeine, particularly with regard to sleep, mood, and performance; 2) the bidirectional effect of caffeine on sleep in children and adolescents and the association of caffeine with other sleep-related practices, and 3) the evidence that supports caffeine as a performance and mood enhancer as well as a countermeasure to sleepiness in the pediatric population. Finally, gaps in knowledge are identified, and a direction for future research is outlined.

Effects of energy drinks on blood pressure, heart rate, and electrocardiographic parameters: An experimental study on healthy young adults

Objective:

To evaluate the effects of the consumption of energy drinks on cardiovascular parameters in a group of healthy young individuals.

Methods:

In a quasi-experimental study, 44 healthy adult participants aged between 15 and 30 years were evaluated. The blood pressure (BP) as well as electrocardiographic indices, including heart rate (HR), PR interval, QRS duration, corrected QT (QTc) interval, and ST-T changes were recorded before consumption of a caffeine-containing energy drink and at the specific time points over a 4-h test duration.

Results:

We found statistically significant HR decline (p=0.004) and more frequent ST-T changes (p=0.004) after the participants consumed the energy drink. However, readings for systolic BP (p=0.44), diastolic BP (p=0.26), PR interval (p=0.449), QRS duration (p=0.235), and QTc interval (p=0.953) showed no significant change post-consumption.

Conclusion:

In conclusion, we demonstrated that the consumption of energy drinks could contribute to HR decline and ST-T change in healthy young adults.

[Abuse of energy drinks: does it pose a risk?]

BACKGROUND

Energy drinks designate "any product in the form of a drink or concentrated liquid containing a mixture of ingredients having the property to raise the level of energy and liveliness". Their introduction has raised many reluctance and reserves after numerous cardiovascular and neurological injuries among regular consumers.

OBJECTIVE

This article attempts to synthesize the existing literature on energy drinks. The review focuses to show that excessive energy drinks consumption cause many complications.

METHODS

The literature review was conducted from 2001 to 2014, using PubMed, Google Scholar, EMBASE, and PsycInfo, using the following keywords alone or combined: energy drinks, caffeine, taurine, toxicity, dependence, complications.

RESULTS

Occasional or moderate consumption of these cans seem to present little risk to healthy adults. However, their repeated consumption in proportions that far exceed the recommendations for recommended use by the manufacturers, combined with the use of alcohol or illicit drugs consumption increases the risk of occurrence of somatic and psychiatric complications, especially among underage, and subjects with cardiovascular and neurological history.

CONCLUSION

Repeated consumption of energy drinks increases the risk of somatic and psychiatric complications. Further studies must be controlled to improve our understanding of other possible negative consequences on health.

Adrenergic System Activation Mediates Changes in Cardiovascular and Psychomotoric Reactions in Young Individuals after Red Bull (©) Energy Drink Consumption

Objectives. To assess the effect of Red Bull(©) on (1) blood glucose and catecholamine levels, (2) cardiovascular and respiratory function changes before, during, and after exercise, (3) reaction time, (4) cognitive functions, and (5) response to mental stress test and emotions in young healthy individuals (N=38). Methods. Heart rate (HR) and arterial blood pressure (ABP), blood glucose, adrenaline, and noradrenalin plasma levels were measured before and after Red Bull(©) intake. Participants were subjected to 4 different study protocols by randomized order, before and 30 minutes after consumption of 500 mL of Red Bull(©). Results. Mean ABP and HR were significantly increased at rest after Red Bull(©) intake. Blood glucose level and plasma catecholamine levels significantly increased after Red Bull(©) consumption. Heart rate, respiration rate, and respiratory flow rate were significantly increased during exercise after Red Bull(©) consumption compared to control condition. Intake of Red Bull(©) significantly improved reaction time, performance in immediate memory test, verbal fluency, and subject's attention as well as performance in mental stress test. Conclusion. This study demonstrated that Red Bull(©) has beneficial effect on some cognitive functions and effect on cardiovascular and respiratory system at rest and during exercise by increasing activity of the sympathetic nervous system.

Caffeine and taurine containing energy drink increases left ventricular contractility in healthy volunteers

To investigate the impact of a caffeine and taurine containing energy drink (ED) on myocardial contractility in healthy volunteers using cardiac MR and cardiac MR based strain analysis. 32 healthy volunteers (mean age 28 years) were investigated before and 1 h after consumption of a caffeine and taurine containing ED. For assessment of global cardiac functional parameters balanced SSFP-Cine imaging was performed, whereas CSPAMM tagging was used to evaluate global and regional myocardial strain. In addition, ten randomly chosen subjects were investigated once more using a caffeine only protocol to further evaluate the effect of caffeine solely. Heart rate and blood pressure were recorded throughout all studies. ED consumption led to a significant increase in peak systolic strain (PSS) and peak systolic strain rate (PSSR) 1 h after consumption (PSS: w/o ED -22.8 ± 2.1%; w ED -24.3 ± 2.4%, P = <0.0001 and PSSR: w/o ED -1.2 ± 0.1 1/s; w ED -1.3 ± 0.2 1/s, P = 0.0056), which was not observed in the caffeine only group. In contrast, global left ventricular function was unchanged (P = 0.2076). No significant changes of vital parameters and diastolic filling pattern were detected 1 h after ED consumption. Consumption of a caffeine and taurine containing ED results in a subtle, but significant increase of myocardial contractility 1 h after consumption.

Effects of energy drink major bioactive compounds on the performance of young adults in fitness and cognitive tests: a randomized controlled trial

Background

The consumption of beverages containing caffeine and taurine before exercising has been associated with increased physical and psychological performances and has been promoted to support the emotional state and provide vitality to consumers. However, there are contradictory results on these issues, it is not clear the effect of every major compound in relation to the whole effect of the beverages and there is a lack in knowledge about their degree of safety for consumption.

Methods

This study used a double-blind, placebo controlled, randomized, crossover design. Fourteen male volunteer soldiers from the Colombian army performed different tests to measure their cardiorespiratory fitness (VO₂max and maximum heart rate), time to exhaustion, strength (isometric strength), power (vertical jump), concentration (Grid test) and memory (Digits test) after drinking 250 ml of one of the following beverages: one with 80 mg caffeine, one with 1000 mg taurine, one with 80 mg caffeine plus 1000 mg taurine, a commercial energy drink (Red Bull®) or a placebo drink. Subjects were caffeine-consumers that avoided caffeine during the day of evaluation. All beverages were matched in flavor and other organoleptic properties to the commercial one, were bottled in dark plastic bottles and were administered in identical conditions to the participants. Differences between treatments were assessed using repeated measures and analysis of variance.

Results

The mean ± SD values of VO₂max, maximum heart rate, time to exhaustion, right handgrip strength, left handgrip strength, vertical jump, Grid test and Digits test were 61.3 ± 6.2 ml/kg.min, 196 ± 6.8 beats per min, 17 ± 1.2 min, 56.8 ± 6.6 kgf, 53.1 ± 5.9 kgf, 41.1 ± 3.8 cm, 19.9 ± 5.9 observed digits and 10.9 ± 3.1 remembered digits after drinking a placebo drink. Comparisons among the commercial drink, caffeine, taurine, caffeine plus taurine and placebo treatments did not show statistically differences in the results of the performed tests. No adverse effects were reported by the participants.

Conclusion

The consumption of caffeine (80 mg) and taurine (1000 mg) or their combination does not increase the physical and cognitive ability in young adults during exercise.

Cardio- and cerebrovascular responses to the energy drink Red Bull in young adults: a randomized cross-over study

PURPOSE

Energy drinks are beverages containing vasoactive metabolites, usually a combination of caffeine, taurine, glucuronolactone and sugars. There are concerns about the safety of energy drinks with some countries banning their sales. We determined the acute effects of a popular energy drink, Red Bull, on cardiovascular and hemodynamic variables, cerebrovascular parameters and microvascular endothelial function.

METHODS

Twenty-five young non-obese and healthy subjects attended two experimental sessions on separate days according to a randomized crossover study design. During each session, primary measurements included beat-to-beat blood pressure measurements, impedance cardiography and transcranial Doppler measurements for at least 20 min baseline and for 2 h following the ingestion of either 355 mL of the energy drink or 355 mL of tap water; the endothelial function test was performed before and two hours after either drink.

RESULTS

Unlike the water control load, Red Bull consumption led to increases in both systolic and diastolic blood pressure (p < 0.005), associated with increased heart rate and cardiac output (p < 0.05), with no significant changes in total peripheral resistance and without diminished endothelial response to acetylcholine; consequently, double product (reflecting myocardial load) was increased (p < 0.005). Red Bull consumption also led to increases in cerebrovascular resistance and breathing frequency (p < 0.005), as well as to decreases in cerebral blood flow velocity (p < 0.005) and end-tidal carbon dioxide (p < 0.005).

CONCLUSION

Our results show an overall negative hemodynamic profile in response to ingestion of the energy drink Red Bull, in particular an elevated blood pressure and double product and a lower cerebral blood flow velocity.

Beverages Of Daily Life: Impact Of Caffeine On Atrial Fibrillation

In recent years, clinical and observational studies reported that caffeine consumption was associated with cardiac arrhythmias, affected heart rate variability, and subsequently increased cardiovascular risk. The analysis of these paper shows that data are controversial and strongly depends on methodology. Moderate intake of caffeine seems to have protective effects on arrhythmias, on contrary high intake of caffeine seems to be associated with increased risk of atrial fibrillation. There is a deep difference when we analysed intake of caffeine from coffee compared to other sources. In very recent time an increase in caffeinated beverages, namely energy drinks, has been reported in young people and several arrhythmic complications has been observed. A review of literature is presented.

Effect of taurine and potential interactions with caffeine on cardiovascular function

The major impetus behind the rise in energy drink popularity among adults is their ability to heighten mental alertness, improve physical performance and supply energy. However, accompanying the exponential growth in energy drink usage have been recent case reports and analyses from the National Poison Data System, raising questions regarding the safety of energy drinks. Most of the safety concerns have centered on the effect of energy drinks on cardiovascular and central nervous system function. Although the effects of caffeine excess have been widely studied, little information is available on potential interactions between the other active ingredients of energy drinks and caffeine. One of the active ingredients often mentioned as a candidate for interactions with caffeine is the beta-amino acid, taurine. Although taurine is considered a conditionally essential nutrient for humans and is thought to play a key role in several human diseases, clinical studies evaluating the effects of taurine are limited. However, based on this review regarding possible interactions between caffeine and taurine, we conclude that taurine should neutralize several untoward effects of caffeine excess. In agreement with this conclusion, the European Union's Scientific Committee on Food published a report in March 2003 summarizing its investigation into potential interactions of the ingredients in energy drinks. At the cardiovascular level, they concluded that "if there are any interactions between caffeine and taurine, taurine might reduce the cardiovascular effects of caffeine." Although these interactions remain to be further examined in humans, the physiological functions of taurine appear to be inconsistent with the adverse cardiovascular symptoms associated with excessive consumption of caffeine-taurine containing beverages.

Cardiovascular and ride time-to-exhaustion effects of an energy drink

Background

Currently, there are few studies on the cardiovascular and fatigue effects of commercially available energy drinks. This study investigated the effects of Monster energy drink (Monster Beverage Corporation, Corona, California), on resting heart rate (HR), heart rate variability (HRV), ride time-to-exhaustion, peak exercise HR, respiratory exchange ratio (RER), and peak rating of perceived exertion (RPE).

Methods

The study used a double-blind, randomized, placebo controlled, crossover design. After an 8-hr fast, 15 subjects consumed Monster Energy Drink (ED standardized to 2.0 mg * kg^-1 caffeine) or a flavor-matched placebo preexercise. Resting HR and HRV were determined. After an initial submaximal workload for 30 minutes, subjects completed 10 min at 80% ventilatory threshold (VT) and rode until volitional fatigue at 100% VT.

Results

Resting HR was significantly different (ED: 65+/-10 bpm vs. placebo: 58+/-8 bpm, p = 0.02), but resting HRV was not different between the energy drink and placebo trials. Ride time-to-exhaustion was not significantly different between trials (ED: 45.5+/- 9.8 vs. placebo: 43.8+/-9.3 min, p = 0.62). No difference in peak RPE (ED: 9.1 +/- 0.5 vs. placebo: 9.0 +/- 0.8, p = 1.00) nor peak HR (ED: 177 +/- 11 vs. placebo: 175 +/- 12, p = 0.73) was seen. The RER at 30% of VT was significantly different (ED: 0.94 +/- 0.06 vs. placebo: 0.91 +/- 0.05, p = 0.046), but no difference between the two conditions were seen at the other intensities.

Conclusion

Although preexercise ingestion of the energy drink does increase resting HR there was no alteration in HRV parameters. Ride time-to-exhaustion was not enhanced.

Assessment of pattern for consumption and awareness regarding energy drinks among medical students

BACKGROUND

Energy drink is a type of beverage which contains stimulant drugs chiefly caffeine and marketed as mental and physical stimulator. Coffee, tea, soft drinks and other caffeinated beverages are not considered as energy drinks. Purpose of our study was to evaluate the awareness of medical students regarding energy drinks and their pattern and reason of energy drinks consumption.

METHODS

This was a cross sectional and observational study conducted during the period of January - December 2012 at four Medical Colleges (Dow Medical College, Sindh Medical College, Jinnah Medical College and Liaquat National Medical College) of Karachi, Pakistan. Over all 900 M.B.B.S students were invited to participate after taking written consent but viable questionnaire was submitted by 866 students, estimated response rate of 96%. All data was entered and analyzed through SPSS version 19.

RESULT

Out of 866 participants, majority were females 614 (70.9%) and only 252 (28.5%) were males, with a mean age of 21.43 ± 1.51 years. Energy drinks users were 350 (42.89%) and non users were 516 (59.58%). Only 102 (29.3%) users and 159 (30.7%) non users know the correct definition of Energy drinks. Regarding awareness, mostly user and non users thought that usage of energy drinks had been on rise due to its usefulness in reducing sleep hours [users193 (43.9%), nonusers 247 (56.1%) (p < 0.05)], for studying or completing major projects [users184 (45.0%), nonusers 225 (55.0%) (p < 0.05)] and for refreshment purposes [users179 (44.9%), nonusers 220 (55.1%) (p < 0.05)]. Two main reasons of not using energy drinks by non-users were "awareness from its side effects" 247 (47.8%) and "have no specific reason" 265 (51.3%). Most common side effects reported by users were fatigue 111 (31.7%) and weight gain 102 (29.4%).

CONCLUSION

In sum, the fact that despite serious side effects of weight gaining and fatigue, practice of consuming energy drinks is highly prevalent among medical students, particularly because they are ever ready to boost their energy level and reduce sleep hours due to stress of exams and projects. This warrants the creation of continued public health awareness about the appropriate use of caffeinated beverages, their potential benefits, side effects and correction of wrong perceptions.

Acute effects of an energy drink on myocardial function assessed by conventional echo-Doppler analysis and by speckle tracking echocardiography on young healthy subjects

Purpose. Previous studies have underlined the effects of the energy drinks containing caffeine end taurine on the cardiovascular system. The aim of this study was to determine acute changes on echocardiographic parameters assessed by conventional echo-Doppler analysis and by speckle tracking echocardiography after the consumption of an energy drink in a young healthy population. Methods. measurement of blood pressure, electrocardiographic, and echocardiographic examination were performed on 35 healthy subjects (mean age 25 ± 2 years, 16 men), at baseline and one hour after the consumption of a body surface area indexed amount of an energy drink (168 mL/m²) containing caffeine (0.03%) and taurine (0.4%). Results. The analysis of left ventricular function showed a significant increase of mean relative values of MAPSE (+11%; P < 0.001), global longitudinal strain (+10%, P = 0.004), and left ventricular twisting (+22%, P < 0.0001) in respect to baseline. Also, right ventricular function parameters appeared significantly increased after energy drink consumption, as TAPSE (+15%, P < 0.0001), global, and free wall right ventricular longitudinal strain (+8%, P = 0.001; +5%, P = 0.1, resp.). Conclusion. In conclusion, the consumption of the ED in our population showed a significant increase of right and left ventricular myocardial function, suggesting a possible positive inotropic effect related to the substances contained therein.

International Society of Sports Nutrition position stand: energy drinks

Position Statement: The International Society of Sports Nutrition (ISSN) bases the following position stand on a critical analysis of the literature on the safety and efficacy of the use of energy drinks (ED) or energy shots (ES). The ISSN has concluded the following. 1. Although ED and ES contain a number of nutrients that are purported to affect mental and/or physical performance, the primary ergogenic nutrients in most ED and ES appear to be carbohydrate and/or caffeine. 2. The ergogenic value of caffeine on mental and physical performance has been well-established but the potential additive benefits of other nutrients contained in ED and ES remains to be determined. 3. Consuming ED 10-60 minutes before exercise can improve mental focus, alertness, anaerobic performance, and/or endurance performance. 4. Many ED and ES contain numerous ingredients; these products in particular merit further study to demonstrate their safety and potential effects on physical and mental performance. 5. There is some limited evidence that consumption of low-calorie ED during training and/or weight loss trials may provide ergogenic benefit and/or promote a small amount of additional fat loss. However, ingestion of higher calorie ED may promote weight gain if the energy intake from consumption of ED is not carefully considered as part of the total daily energy intake. 6. Athletes should consider the impact of ingesting high glycemic load carbohydrates on metabolic health, blood glucose and insulin levels, as well as the effects of caffeine and other stimulants on motor skill performance. 7. Children and adolescents should only consider use of ED or ES with parental approval after consideration of the amount of carbohydrate, caffeine, and other nutrients contained in the ED or ES and a thorough understanding of the potential side effects. 8. Indiscriminant use of ED or ES, especially if more than one serving per day is consumed, may lead to adverse events and harmful side effects. 9. Diabetics and individuals with pre-existing cardiovascular, metabolic, hepatorenal, and neurologic disease who are taking medications that may be affected by high glycemic load foods, caffeine, and/or other stimulants should avoid use of ED and/or ES unless approved by their physician.

Differential cognitive effects of energy drink ingredients: caffeine, taurine, and glucose

Energy drinks containing caffeine, taurine, and glucose may improve mood and cognitive performance. However, there are no studies assessing the individual and interactive effects of these ingredients. We evaluated the effects of caffeine, taurine, and glucose alone and in combination on cognitive performance and mood in 24-hour caffeine-abstained habitual caffeine consumers. Using a randomized, double-blind, mixed design, 48 habitual caffeine consumers (18 male, 30 female) who were 24-hour caffeine deprived received one of four treatments (200 mg caffeine/0 mg taurine, 0 mg caffeine/2000 mg taurine, 200 mg caffeine/2000 mg taurine, 0 mg caffeine/0 mg taurine), on each of four separate days, separated by a 3-day wash-out period. Between-participants treatment was a glucose drink (50 g glucose, placebo). Salivary cortisol, mood and heart rate were measured. An attention task was administered 30-minutes post-treatment, followed by a working memory and reaction time task 60-minutes post-treatment. Caffeine enhanced executive control and working memory, and reduced simple and choice reaction time. Taurine increased choice reaction time but reduced reaction time in the working memory tasks. Glucose alone slowed choice reaction time. Glucose in combination with caffeine, enhanced object working memory and in combination with taurine, enhanced orienting attention. Limited glucose effects may reflect low task difficulty relative to subjects' cognitive ability. Caffeine reduced feelings of fatigue and increased tension and vigor. Taurine reversed the effects of caffeine on vigor and caffeine-withdrawal symptoms. No effects were found for salivary cortisol or heart rate. Caffeine, not taurine or glucose, is likely responsible for reported changes in cognitive performance following consumption of energy drinks, especially in caffeine-withdrawn habitual caffeine consumers.

The effects of energy beverages on cultured cells

The popularity and prevalence of energy beverages makes it essential to examine the interactions between the ingredients and their effects on the safety of these beverages. In this study, we used in vitro assays to examine the effects of two energy beverages on mesenchymal, epithelial and neuronal cells. Our results showed that treatment of epithelial and mesenchymal cells with either energy beverage resulted in a dose dependent delay in wound closure, in a scratch wound healing assay. In rat embryonic fibroblasts, treatment with the energy beverages led to decreased lamellipodia formation and decreased proliferation/viability; whereas in MDCK cells, energy beverage treatment resulted in actin disorganization without any effects on cell proliferation. This suggests that the mechanisms underlying delayed wound healing might be different in the two cell types. Interestingly, the delays in both cell types could not be mimicked by treatment of caffeine, taurine and glucose alone or in combinations. Furthermore, treatment of chick forebrain neuronal cultures with energy beverages resulted in a dose dependent inhibition of neurite outgrowth. The cellular assays used in this study provide a consistent, qualitative and quantitative system for examining the combinatorial effects of the various ingredients used in energy beverages.

A survey of energy drinks consumption practices among student -athletes in Ghana: lessons for developing health education intervention programmes

BACKGROUND

Globally, young adults and college athletes are primary targets of the marketing campaigns of energy drink companies. Consequently, it is reported that young adults and college athletes consume energy drinks frequently. The purpose of this study was to determine the prevalence of energy drink consumption among student-athletes selected from seven public universities in Ghana. The study assessed the energy drink consumption patterns, types usually consumed, frequency of consumption and reasons why athletes consumed energy drinks.

METHODS

A total number of 180 student-athletes gave their consent to participate in the study and completed a questionnaire which was administered during an inter-university sports competition.

RESULTS

Most of the participants (62.2%) reported consuming at least one can of energy drink in a week. A high proportion (53.6%) of the respondents who drink energy drinks indicated that they did so to replenish lost energy after training or a competition. Other reasons given as to why energy drinks were consumed by the study participants included to provide energy and fluids to the body (25.9%), to improve performance (9.8%) and to reduce fatigue (5.4%).

CONCLUSION

These results suggest the need to plan health education programmes to particularly correct some wrong perceptions that athletes have regarding the benefits of energy drinks and also create awareness among student-athletes about the side effects of excessive intake of energy drinks.

Intracerebroventricular administration of taurine impairs learning and memory in rats

OBJECTIVES

Taurine is a semi-essential amino acid widely distributed in the body and we take in it from a wide range of nutritive-tonic drinks to improve health. To date, we have elucidated that oral supplementation of taurine does not affect learning and memory in the rat. However, there are few studies concerning the direct effects of taurine in the brain at the behavior level. In this study, we intracerebroventricularly administered taurine to rats and aimed to elucidate the acute effects on learning and memory using the Morris water maze method.

METHODS

Escape latency, swim distance, and distance to zone, which is the integral of the distance between the rats and the platform for every 0.16 seconds, were adopted as parameters of the ability of learning and memory. We also tried to evaluate the effect of intraperitoneal taurine administration.

RESULTS

Escape latency, swim distance, and distance to zone were significantly longer in the intracerebroventricularly taurine-administered rats than in the saline-administered rats. Mean swimming velocity was comparable between these two groups, although the physical performance was improved by taurine administration. Probe trials showed that the manner of the rats in finding the platform was comparable. In contrast, no significant differences were found between the intraperitoneally taurine-administered rats and the saline-administered rats.

DISCUSSION

These results indicate that taurine administered directly into the brain ventricle suppresses and delays the ability of learning and memory in rats. In contrast, it is implied that taurine administered peripherally was not involved in learning and memory.

Increased alcohol consumption, nonmedical prescription drug use, and illicit drug use are associated with energy drink consumption among college students

OBJECTIVES

This longitudinal study examined the prevalence and correlates of energy drink use among college students, and investigated its possible prospective associations with subsequent drug use, including nonmedical prescription drug use.

METHODS

Participants were 1,060 undergraduates from a large, public university who completed three annual interviews, beginning in their first year of college. Use of energy drinks, other caffeinated products, tobacco, alcohol, and other illicit and prescription drugs were assessed, as well as demographic and personality characteristics.

RESULTS

Annual weighted prevalence of energy drink use was 22.6%(wt) and 36.5%(wt) in the second and third year of college, respectively. Compared to energy drink non-users, energy drink users had heavier alcohol consumption patterns, and were more likely to have used other drugs, both concurrently and in the preceding assessment. Regression analyses revealed that Year 2 energy drink use was significantly associated with Year 3 nonmedical use of prescription stimulants and prescription analgesics, but not with other Year 3 drug use, holding constant demographics, prior drug use, and other factors.

CONCLUSIONS

A substantial and rapidly-growing proportion of college students use energy drinks. Energy drink users tend to have greater involvement in alcohol and other drug use and higher levels of sensation-seeking, relative to non-users of energy drinks. Prospectively, energy drink use has a unique relationship with nonmedical use of prescription stimulants and analgesics. More research is needed regarding the health risks associated with energy drink use in young adults, including their possible role in the development of substance use problems.

[Risks of energy drinks in youths]

The market value for energy drinks is continually growing and the annual worldwide energy drink consumption is increasing. However, issues related to energy drink ingredients and the potential for adverse health consequences remain to be elucidated. This aim of the present paper is to review the current knowledge on putative adverse effects of energy drinks, especially in youths. There are many energy drink brands in the worldwide market, even if only few brands are available in France. Although the energy drink content varies, these beverages often contain taurine, caffeine, vitamins B and carbohydrates. These drinks vary widely in both caffeine content (80 to 141 mg per can) and caffeine concentration. Except caffeine, the effects of energy drink ingredients on physical and cognitive performances remain controversial. Researchers identified moderate positive effects of energy drinks on performances, whereas others found contrary results. The adverse effects of energy drink can be related to either the toxicity of ingredients or specific situations in which energy drinks are used such as ingestion in combination with alcohol. Although the issue of taurine-induced toxic encephalopathy has been addressed, it is likely that the risk of taurine toxicity after energy drink consumption remains low. However, whether the prolonged use of energy drinks providing more than 3g taurine daily remains to be examined in the future. The consumption of energy drinks may increase the risk for caffeine overdose and toxicity in children and teenagers. The practice of consuming great amounts of energy drink with alcohol is considered by many teenagers and students a primary locus to socialize and to meet people. This pattern of energy drink consumption explains the enhanced risk of both caffeine and alcohol toxicity in youths. Twenty five to 40% of young people report consumption of energy drink with alcohol while partying. Consumption of energy drinks with alcohol during heavy episodic drinking is at risk of serious injury, sexual assault, drunk driving, and death. However, even after adjusting for alcohol consumption, students who consume alcohol mixed with energy drinks had dramatically higher rates of serious alcohol-related consequences. It has been reported that the subjective perceptions of some symptoms of alcohol intoxication are less intense after the combined ingestion of the alcohol plus energy drink; however, these effects are not detected in objective measures of motor coordination and visual reaction time.

Perceived stress, energy drink consumption, and academic performance among college students

OBJECTIVE

This study explored relationships regarding perceived stress, energy drink consumption, and academic performance among college students.

PARTICIPANTS

Participants included 136 undergraduates attending a large southern plains university.

METHODS

Participants completed surveys including items from the Perceived Stress Scale(1) and items to describe energy drink consumption, academic performance, and demographics.

RESULTS

Positive correlations existed between participants' perceived stress and energy drink consumption. Participants' energy drink consumption and academic performance were negatively correlated. Freshmen (M = 0.330) and sophomores (M = 0.408) consumed a lower number of energy drinks yesterday than juniors (M = 1.000). Males reported higher means than females for selected energy drink consumption items. Statistically significant interactions existed between gender and year in school for selected energy drink consumption items.

CONCLUSIONS

Results confirm gender differences in energy drink consumption and illuminate a need for education regarding use of energy drinks in response to perceived stress.

Effect of Red Bull energy drink on cardiovascular and renal function

Energy drink consumption has been anecdotally linked to the development of adverse cardiovascular effects in consumers, although clinical trials to support this link are lacking. The effects of Red Bull energy drink on cardiovascular and neurologic functions were examined in college-aged students enrolled at Winona State University. In a double-blind experiment where normal calorie and low calorie Red Bull were compared to normal and low calorie placebos, no changes in overall cardiovascular function nor blood glucose (mg/dL) were recorded in any participant (n = 68) throughout a 2-h test period. However, in the second experiment, nine male and twelve female participants subjected to a cold pressor test (CPT) before and after Red Bull consumption showed a significant increase in blood sugar levels pre- and post Red Bull consumption. There was a significant increase in diastolic blood pressure of the male volunteers immediately after submersion of the hand in the 5 degrees C water for the CPT. Under the influence of Red Bull, the increase in diastolic pressure for the male participants during the CPT was negated. There were no significant changes in the blood pressure of the female participants for the CPT with or without Red Bull. Finally, the CPT was used to evaluate pain threshold and pain tolerance before and after Red Bull consumption. Red Bull consumption was associated with a significant increase in pain tolerance in all participants. These findings suggest that Red Bull consumption ameliorates changes in blood pressure during stressful experiences and increases the participants' pain tolerance.

Effect of "energy drink" consumption on hemodynamic and electrocardiographic parameters in healthy young adults

BACKGROUND

Energy drinks are frequently purported to improve cognitive function and concentration. However, the cardiovascular effects of these drinks have not been adequately studied.

OBJECTIVE

To determine the cardiac effects of a commercially available, multicomponent energy drink in healthy volunteers.

METHODS

Fifteen healthy adults were included in this prospective study. Individuals who had chronic medical conditions, were on chronic medication, or were pregnant or breast-feeding were excluded. Subjects abstained from caffeine for 48 hours prior to and during the study. In the morning on Day 1 of the study, while subjects were in a fasted state, baseline blood pressure (BP), heart rate (HR), and electrocardiographic (ECG) parameters were measured. Participants then consumed 500 mL (2 cans) of an energy drink and measurements were repeated 30 minutes, 1 hour, 2 hours, 3 hours, and 4 hours later. Participants then drank 500 mL of energy drink daily for the next 5 days. Day 1 protocol was repeated on Day 7.

RESULTS

On Days 1 and 7, maximum mean systolic BP (SBP), HR, and QTc interval occurred at 4 hours. Maximum diastolic BP (DBP) occurred at 2 hours on Days 1 and 7. Within 4 hours of energy drink consumption, on Days 1 and 7, respectively, SBP increased by 7.9% (p = 0.006) and 9.6% (p < 0.001), HR increased by 7.8% (p = 0.009) and 11.0% (p < 0.001), and QTc interval increased by 2.4% (p = 0.368) and 5.0% (p = 0.052). DBP increased by 7.0% (p = 0.046) and 7.8% (p = 0.063) within 2 hours of energy drink consumption on Days 1 and 7, respectively.

CONCLUSIONS

Although no significant ECG changes were observed, HR increased 5-7 beats/min and SBP increased 10 mm Hg after energy drink consumption.