Can energy drinks increase the desire for more alcohol?

The rewarding effects of alcohol after bariatric surgery: do they change and are they associated with pharmacokinetic changes?

BACKGROUND

Research shows that surgery patients who have undergone Roux-en-Y gastric bypass (RYGB) are at increased risk for an alcohol use disorder (AUD). However, the mechanisms through which this increased risk is incurred are poorly understood. A host of variables have been proposed as potentially causal in developing AUDs, but empirical examination of many of these variables in human samples is lacking.

OBJECTIVES

Our objective was to examine the extent to which alcohol pharmacokinetics (PK), the rewarding effects of alcohol, and the relationship between these variables change from before to after weight loss surgery.

SETTING

Large healthcare facility in the Midwest United States METHODS: Thirty-four participants completed assessments before and 1 year after RYGB. They completed laboratory sessions and provided data on the PK of alcohol and the extent to which alcohol was reinforcing to them at each timepoint.

RESULTS

Findings show that the PK effects of alcohol (P < .01) and how rewarding alcohol was reported to be (P < .01) changed from before to 1 year after weight loss surgery. Further, statistically significant increases in the association between these variables were witnessed from before to 1 year after surgery (P < .01).

CONCLUSION

These results implicate changes (from before surgery to one year after) in the reinforcing and PK effects of alcohol as possible mechanisms for increased risk of alcohol use disorder following Roux-en-Y gastric bypass surgery.

Trends in energy drink and combined alcohol and energy drinks consumption among Italian high school students, 2008-2019

BACKGROUND

Energy Drinks (ED) are caffeinated beverages marketed as attention and endurance enhancers. The main purpose of this study is to provide national estimates of the prevalence of alcohol mixed with energy drink (AmED) and ED use among school-aged adolescents. A secondary objective is to examine the differences in the prevalence of AmED and ED consumption by gender.

METHODS

For this study, we used data from twelve consecutive years, from ESPAD-Italia®2008 to ESPAD-Italia®2019.

RESULTS

From 2008-2019, the prevalence of lifetime consumption of energy drinks increased significantly for male (64.5-75.7%, p < 0.001) and female (46.8-61.8%, p < 0.001). We also observed an increase in both genders for last year prevalence (male: 51.6-63.4%, p < 0.001; female: 32.5-38.3%, p < 0.001), instead prevalence in last month showed an increase only in males (males: 37.5-45.4%, p = <0.001; females: 19.9-20.3%, p = 0.426). Finally, frequent use showed a fluctuating trend, particularly in females (males: 3.2-4.3%, p = 0.422; females: 0.8-0.8%, p = 0.643). From 2013-2019, the prevalence of AmED consumption did not show relevant changes among adolescents. A clear gender gap is evident for both ED and AmED usage prevalence, in all the years considered for lifetime, last year, last month and frequent use.

CONCLUSIONS

The findings suggest that the prevalence of ED consumption among Italian high school students is very high and has grown substantially over the past 12 years. Differently the prevalence of AmED use, although widespread, did not increase overall since 2013.

Caffeine increases alcohol self-administration, an effect that is independent of dopamine D2 receptor function

The rising popularity of alcohol mixed with energy drinks (AmEDs) has become a significant public health concern, with AmED users reporting higher levels of alcohol intake than non-AmED users. One mechanism proposed to explain this heightened level of alcohol intake in AmED users is that the high levels of caffeine found in energy drinks may increase the positive reinforcing properties of alcohol, an effect that may be dependent on interactions between adenosine receptor signaling pathways and the dopamine D₂ receptor. Therefore, the purpose of the current study was to confirm whether caffeine does increase the positive reinforcing effects of alcohol using both fixed ratio (FR) and progressive ratio (PR) designs, and to investigate a potential role of the dopamine D₂ receptor to caffeine-induced increases in alcohol self-administration. Male Long-Evans rats were trained to self-administer a sweetened alcohol solution (10% v/v alcohol + 2% w/v sucrose) on an FR2 schedule of reinforcement, and the effects of caffeine (0, 5, 10, and 20 mg/kg, i. p. [intraperitoneally]) on the maintenance of alcohol self-administration and alcohol break point were examined. Parallel experiments in rats trained to self-administer sucrose (0.8% w/v) were conducted to determine whether caffeine's reinforcement-enhancing effects extended to a non-drug reinforcer. Caffeine pretreatment (5-10 mg/kg) significantly increased sweetened alcohol self-administration and motivation for a sweetened alcohol reinforcer. However, similar increases in self-administration of a non-drug reinforcer were not observed. Contrary to our hypothesis, the D₂ receptor antagonist eticlopride did not block a caffeine-induced increase in sweetened alcohol self-administration, nor did it alter caffeine-induced increases in motivation for a sweetened alcohol reinforcer. Taken together, these results support the hypothesis that caffeine increases the positive reinforcing effects of alcohol, which may explain caffeine-induced increases in alcohol intake. However, the reinforcement-enhancing effects of caffeine appear to be independent of D₂ receptor function.

Association between energy drink consumption, depression and suicide ideation in Korean adolescents

BACKGROUND

Suicide is the leading cause of death among adolescents in South Korea. Negative influences of the abuse of energy drinks on mental health problems have emerged.

AIMS

This study aimed to analyze the relationship between energy drink consumption, depression and suicide ideation.

METHODS

We analyzed the data of 26,346 boys and 26,966 girls who participated in the 2015 Korean Youth Risk Behavior Web-Based Survey. The independent variable was the frequency of energy drink consumption per week. Experience of depression and suicide ideation were considered as the dependent variables. Multiple logistic regression was performed.

RESULTS

An association was found between energy drink intake per week and depressive mood. Moreover, the most frequent energy drink intake (three times or more per week) group showed the highest association with depressive mood (odds ratios (ORs); boys: ORs = 1.40, 95% confidence interval (CI): 1.25-1.56; girls: ORs = 1.61, 95% CI: 1.44-1.79) and suicide ideation (boys: ORs = 1.46, 95% CI: 1.27-1.69; girls: ORs = 1.36, 95% CI: 1.20-1.55).

CONCLUSION

We observed that consumption of excessive amounts of energy drinks is associated with depression and suicide ideation. Therefore, appropriate regulation or education is needed to prevent adolescents from experiencing adverse outcomes.

Supplemental taurine during adolescence and early adulthood has sex-specific effects on cognition, behavior and neurotransmitter levels in C57BL/6J mice dependent on exposure window

The mammalian brain goes through final maturation during late adolescence and early adulthood with sex differences in timing. The key cellular processes, including changes in neurotransmitter receptor density and synaptic pruning, make this age uniquely vulnerable to neurotoxic insults. Teenagers and young adults are the major consumers of energy drinks, which contain high levels of taurine and caffeine. Taurine is one of the most abundant amino acids in the central nervous system, but the effects of supplemental taurine consumption during adolescence has not been well studied. We conducted an initial short-term exposure study with 0.12% taurine in drinking water and a long-term exposure dose-response study using 0.06 and 0.12% taurine in male and female C57BL/6J mice. We examined a broad range of cognitive functions and behaviors and measured neurotransmitter levels. We found no significant differences in anxiety, open field locomotor activity, or sensorimotor gating. However, we found impairments in novel object recognition and sex differences in Morris water maze. When taurine treatment stopped before behavioral experiments began, male mice had significant impairments in spatial learning and memory. In the dose-response study when taurine treatment continued throughout behavioral experiments, females had significant impairments. We also found sex differences in neurotransmitter levels with females having higher levels of glutamate, DOPAC and 5-HIAA. We conclude that both females and males are at risk from excess taurine consumption during final brain maturation.

Trends in Energy Drink Consumption Among U.S. Adolescents and Adults, 2003-2016

INTRODUCTION

Energy drinks refer to non-alcoholic beverages that contain caffeine, amino acids, herbs, and vitamins. Although energy drinks are marketed to reduce fatigue and improve physical/mental performance, frequent consumption of these beverages has been linked to negative health consequences. The purpose of this study is to provide timely, national estimates of the percentage of energy drink consumers in the U.S. and to analyze trends in energy drink intake between 2003 and 2016.

METHODS

A total of 9,911 adolescents (aged 12-19 years); 12,103 young adults (aged 20-39 years); and 11,245 middle-aged adults (aged 40-59 years) were assessed using dietary data from the 2003-2016 National Health and Nutrition Examination Surveys. For each age group (adolescents, young adults, and middle-aged adults), logistic regression was used to estimate the proportion of energy drink consumers, and negative binomial regression was used to estimate per capita energy drink consumption, adjusting for covariates. Differences in total caffeine intake between energy drink consumers and non-consumers were examined by pooling all survey years together and using negative binomial regression. Analyses were conducted in 2018.

RESULTS

From 2003 to 2016, the prevalence of energy drink consumption increased significantly for adolescents (0.2% to 1.4%, p=0.028); young adults (0.5% to 5.5%, p<0.001); and middle-aged adults (0.0% to 1.2%, p=0.006). Per capita consumption of energy drinks increased significantly from 2003 to 2016 only for young adults (1.1 to 9.7 calories, p<0.001). Pooled across years, energy drink consumers had significantly higher total caffeine intake compared with non-consumers for adolescents (227.0 mg vs 52.1 mg, p<0.001); young adults (278.7 mg vs 135.3 mg, p<0.001); and middle-aged adults (348.8 mg vs 219.0 mg, p<0.001).

CONCLUSIONS

These findings indicate that consumption of energy drinks has grown substantially and that these drinks are a major source of caffeine among those who consume them.

Intensity of Energy Drink Use Plus Alcohol Predict Risky Health Behaviours among University Students in the Caribbean

The relationship between energy drink (ED) use and risky behaviours has not been explored in the Caribbean, where youth risky behaviours are prevalent. This paper examines the relationship between ED use and risky behaviours and the moderating effect of gender among 1994 undergraduate students in Trinidad and Tobago. Analyses examined the association between ED use and risky behaviours, and the significant predictors of risky behaviours. Analysis of variance determined whether there were differences in risky behaviours between those who used only alcohol or EDs, both alcohol and EDs, alcohol mixed with EDs and neither alcohol nor EDs; and the difference between those with high and low intensity of ED use. In both males and females current use of energy drinks was positively associated with harmful substance use, risky sexual behaviours, and risky non-sexual behaviours, more strongly for males. The strongest predictor of risky behaviours was gender. Males consuming both alcohol and EDs, independently or mixed, were most likely to have risky behaviours. Consistent with previous reports, harmful alcohol use and other risk taking health behaviours appear to be predicted by a combination of high intensity use of EDs and alcohol. In countries like Trinidad and Tobago where violence, alcohol use disorders, STI/HIV infection and teenaged pregnancy are prevalent, the assessment of consumption of EDs and alcohol may be an important potential predictor of health compromising behaviours.

Behavioral effects of the combined use of alcohol and energy drinks on alcohol hangover in an experimental mice model

In last few years it has been a significant increase in the consumption of alcohol combined with energy drink. The aim of this work was to study the effect of this mixture in motor and affective behaviors during an alcohol hangover episode. Male Swiss mice received one of the following treatments: saline + sucrose; saline + energy drink; ethanol + sucrose; ethanol + energy drink. Ethanol dose was 3.8 g/kg BW (i.p.) and energy drink dose was 18 ml/kg BW (gavage) at ZT1 (8 am) (ZT: Zeitgeber time; ZT0: 7 am; lights on). The behavioral tests used were tight rope test to determine motor coordination; hanging wire test to study muscular strength; elevated plus maze and open field tests to evaluate anxiety like-behavior and locomotor activity. Tests were carried out at basal point that matched with lights onset and every 6 h up to 18 h after treatments. Hangover onset was established at ZT7 when blood alcohol concentration (BAC) was almost zero. Our results showed that the mixture of alcohol and energy drink altered significantly motor skills. Specifically, a significant decrease was observed in the performance of the animals in the tightrope and hanging wire tests in groups treated with the mixture of alcohol and energy drink. A significant impairment in the anxiety-like behavior was observed mainly at the beginning of alcohol hangover. These findings suggest that energy drink added to alcohol extends motor disabilities observed during an alcohol hangover episode in comparison with animals that received alcohol alone.

Seizure vulnerability and anxiety responses following chronic co-administration and acute withdrawal of caffeine and ethanol in a rat model

BACKGROUND

Caffeine antagonizes the intoxicating effects of alcohol. Consequently, there has been a dramatic global increase in the consumption of caffeinated drinks together with alcohol, especially among young adults. We assessed the seizure vulnerability and anxiety responses following the chronic co-administration of, and withdrawal from, caffeine and ethanol in male rats.

METHODS

The rats were randomly assigned to six groups consisting of 10 animals each: 10 mg/kg of caffeine, 20 mg/kg of caffeine, 4 g/kg of 20% ethanol, combined caffeine (20 mg/kg) and ethanol (4 g/kg of 20%), 4 mL/kg distilled water, and an untreated control group. The test substances were administered intragastrically twice daily for 29 days. On day 29, the rats were tested on the elevated plus maze to assess anxiety-related responses. On day 30, pentylenetetrazol (PTZ), a chemoconvulsant, was administered intraperitoneally at a dose of 40 mg/kg to the animals. Seizure responses and mortality up to 72 h were recorded.

RESULTS

Compared with the control group, the rats that received chronic treatment with low-dose caffeine, ethanol alone, and combined caffeine and ethanol exhibited significant anxiogenic-like effects, unlike with high-dose caffeine. Both low- and high-dose caffeine significantly increased PTZ seizure latency. Ethanol alone and combined caffeine and ethanol both lowered PTZ seizure latency. No significant difference occurred between the controls and the untreated group for either anxiety or seizure expression. Combined caffeine and ethanol increased the seizure-induced mortality from withdrawal effects at 72 h.

CONCLUSIONS

These findings suggest that the chronic co-administration of caffeine and ethanol and the acute withdrawal from these drugs lead to anxiogenic effects and increased seizure vulnerability.

Taurine, caffeine, and energy drinks: Reviewing the risks to the adolescent brain

Energy drinks are emerging as a major component of the beverage market with sales projected to top $60 billion globally in the next five years. Energy drinks contain a variety of ingredients, but many of the top-selling brands include high doses of caffeine and the amino acid taurine. Energy drink consumption by children has raised concerns, due to potential caffeine toxicity. An additional risk has been noted among college-aged consumers of energy drinks who appear at higher risk of over-consumption of alcohol when the two drinks are consumed together. The differential and combinatorial effects of caffeine and taurine on the developing brain are reviewed here with an emphasis on the adolescent brain, which is still maturing. Key data from animal studies are summarized to highlight both reported benefits and adverse effects reported following acute and chronic exposures. The data suggest that age is an important factor in both caffeine and taurine toxicity. Although the aged or diseased brain might benefit from taurine or caffeine supplementation, it appears that adolescents are not likely to benefit from supplementation and may, in fact, suffer ill effects from chronic ingestion of high doses. Additional work is needed though to address gaps in our understanding of how taurine affects females, since the majority of animal studies focused exclusively on male subjects.

Adenosine A2A receptor mediates hypnotic effects of ethanol in mice

Ethanol has extensive effects on sleep and daytime alertness, causing premature disability and death. Adenosine, as a potent sleep-promoting substance, is involved in many cellular and behavioral responses to ethanol. However, the mechanisms of hypnotic effects of ethanol remain unclear. In this study, we investigated the role of adenosine in ethanol-induced sleep using C57BL/6Slac mice, adenosine A_2A receptor (A_2AR) knockout mice, and their wild-type littermates. The results showed that intraperitoneal injection of ethanol (3.0 g/kg) at 21:00 decreased the latency to non-rapid eye movement (NREM) sleep and increased the duration of NREM sleep for 5 h. Ethanol dose-dependently increased NREM sleep, which was consistent with decreases in wakefulness in C57BL/6Slac mice compared with their own control. Caffeine (5, 10, or 15 mg/kg), a nonspecific adenosine receptor antagonist, dose-dependently and at high doses completely blocked ethanol-induced NREM sleep when administered 30 min prior to (but not after) ethanol injection. Moreover, ethanol-induced NREM sleep was completely abolished in A_2AR knockout mice compared with wild-type mice. These findings strongly indicate that A_2AR is a key receptor for the hypnotic effects of ethanol, and pretreatment of caffeine might be a strategy to counter the hypnotic effects of ethanol.

Health Effects and Public Health Concerns of Energy Drink Consumption in the United States: A Mini-Review

As energy drink consumption continues to grow worldwide and within the United States, it is important to critically examine the nutritional content and effects on population health of these beverages. This mini-review summarizes the current scientific evidence on health consequences from energy drink consumption, presents relevant public health challenges, and proposes recommendations to mitigate these issues. Emerging evidence has linked energy drink consumption with a number of negative health consequences such as risk-seeking behaviors, poor mental health, adverse cardiovascular effects, and metabolic, renal, or dental conditions. Despite the consistency in evidence, most studies are of cross-sectional design or focus almost exclusively on the effect of caffeine and sugar, failing to address potentially harmful effects of other ingredients. The negative health effects associated with energy drinks (ED) are compounded by a lack of regulatory oversight and aggressive marketing by the industry toward adolescents. Moreover, the rising trend of mixing ED with alcohol presents a new challenge that researchers and public health practitioners must address further. To curb this growing public health issue, policy makers should consider creating a separate regulatory category for ED, setting an evidence-based upper limit on caffeine, restricting sales of ED, and regulating existing ED marketing strategies, especially among children and adolescents.

Energy drinks and alcohol-related risk among young adults

BACKGROUND

Energy drink consumption, with or without concurrent alcohol use, is common among young adults. This study sought to clarify risk for negative alcohol outcomes related to the timing of energy drink use.

METHODS

The authors interviewed a community sample of 481 young adults, aged 18-25, who drank alcohol in the last month. Past-30-day energy drink use was operationalized as no-use, use without concurrent alcohol, and concurrent use of energy drinks with alcohol ("within a couple of hours"). Negative alcohol outcomes included past-30-day binge drinking, past-30-day alcohol use disorder, and drinking-related consequences.

RESULTS

Just over half (50.5%) reported no use of energy drinks,18.3% reported using energy drinks without concurrent alcohol use, and 31.2% reported concurrent use of energy drinks and alcohol. Relative to those who reported concurrent use of energy drinks with alcohol, and controlling for background characteristics and frequency of alcohol consumption, those who didn't use energy drinks and those who used without concurrent alcohol use had significantly lower binge drinking, negative consequences, and rates of alcohol use disorder (P < .05 for all outcomes). There were no significant differences between the no-use and energy drink without concurrent alcohol groups on any alcohol-related measure (P > .10 for all outcomes).

CONCLUSIONS

Concurrent energy drink and alcohol use is associated with increased risk for negative alcohol consequences in young adults. Clinicians providing care to young adults could consider asking patients about concurrent energy drink and alcohol use as a way to begin a conversation about risky alcohol consumption while addressing 2 substances commonly used by this population.

Acute impact of caffeinated alcoholic beverages on cognition: A systematic review

INTRODUCTION

Energy drinks are popular beverages that are supposed to counteract sleepiness, increase energy, maintain alertness and reduce symptoms of hangover. Cognitive enhancing seems to be related to many compounds such as caffeine, taurine and vitamins. Currently, users mostly combine psychostimulant effects of energy drinks to counteract sedative effects of alcohol. However, recent literature suggests that this combination conducts to feel less intoxicated but still impaired. The goal of the present article is to review cognitive impact and subjective awareness in case of caffeinated alcoholic beverage (CAB) intoxication.

METHOD

PubMed (January 1960 to March 2016) database was searched using the following terms: cognitive impairments, alcohol, energy drinks; cognition, alcohol, caffeine.

RESULTS

99 papers were found but only 12 randomized controlled studies which explored cognitive disorders and subjective awareness associated with acute CAB or AED (alcohol associated with energy drinks) intoxication were included.

DISCUSSION

The present literature review confirmed that energy drinks might counteract some cognitive deficits and adverse effects of alcohol i.e. dry mouth, fatigue, headache, weakness, and perception of intoxication due to alcohol alone. This effect depends on alcohol limb but disappears when the complexity of the task increases, when driving for example. Moreover, studies clearly showed that CAB/AEDs increase impulsivity which conducts to an overconsumption of alcohol and enhanced motivation to drink compared to alcohol alone, potentiating the risk of developing addictive behaviors. This is a huge problem in adolescents with high impulsivity and immature decision making processes.

CONCLUSION

Although energy drinks counteract some cognitive deficits due to alcohol alone, their association promotes the risk of developing alcohol addiction. As a consequence, it is necessary to better understand the neurobiological mechanisms underlying these interactions in order to better prevent the development of alcohol dependence.

Faster self-paced rate of drinking for alcohol mixed with energy drinks versus alcohol alone

The consumption of alcohol mixed with energy drinks (AmED) has been associated with higher rates of binge drinking and impaired driving when compared with alcohol alone. However, it remains unclear why the risks of use of AmED are heightened compared with alcohol alone even when the doses of alcohol consumed are similar. Therefore, the purpose of this laboratory study was to investigate if the rate of self-paced beverage consumption was faster for a dose of AmED versus alcohol alone using a double-blind, within-subjects, placebo-controlled study design. Participants (n = 16) of equal gender who were social drinkers attended 4 separate test sessions that involved consumption of alcohol (1.97 ml/kg vodka) and energy drinks, alone and in combination. On each test day, the dose assigned was divided into 10 cups. Participants were informed that they would have a 2-h period to consume the 10 drinks. After the self-paced drinking period, participants completed a cued go/no-go reaction time (RT) task and subjective ratings of stimulation and sedation. The results indicated that participants consumed the AmED dose significantly faster (by ∼16 min) than the alcohol dose. For the performance task, participants' mean RTs were slower in the alcohol conditions and faster in the energy-drink conditions. In conclusion, alcohol consumers should be made aware that rapid drinking might occur for AmED beverages, thus heightening alcohol-related safety risks. The fast rate of drinking may be related to the generalized speeding of responses after energy-drink consumption. (PsycINFO Database Record

Endothelial Nitric Oxide Mediates Caffeine Antagonism of Alcohol-Induced Cerebral Artery Constriction

Despite preventive education, the combined consumption of alcohol and caffeine (particularly from "energy drinks") continues to rise. Physiologic perturbations by separate intake of ethanol and caffeine have been widely documented. However, the biologic actions of the alcohol-caffeine combination and their underlying subcellular mechanisms have been scarcely studied. Using intravital microscopy on a closed-cranial window and isolated, pressurized vessels, we investigated the in vivo and in vitro action of ethanol-caffeine mixtures on cerebral arteries from rats and mice, widely recognized models to address cerebrovascular pathophysiology and pharmacology. Caffeine at concentrations found in human circulation after ingestion of one to two cups of coffee (10 µM) antagonized the endothelium-independent constriction of cerebral arteries evoked by ethanol concentrations found in blood during moderate-heavy alcohol intoxication (40-70 mM). Caffeine antagonism against alcohol was similar whether evaluated in vivo or in vitro, suggesting independence of systemic factors and drug metabolism, but required a functional endothelium. Moreover, caffeine protection against alcohol increased nitric oxide (NO•) levels over those found in the presence of ethanol alone, disappeared upon blocking NO• synthase, and could not be detected in pressurized cerebral arteries from endothelial nitric-oxide synthase knockout (eNOS(-/-)) mice. Finally, incubation of de-endothelialized cerebral arteries with the NO• donor sodium nitroprusside (10 µM) fully restored the protective effect of caffeine. This study demonstrates for the first time that caffeine antagonizes ethanol-induced cerebral artery constriction and identifies endothelial NO• as the critical caffeine effector on smooth muscle targets. Conceivably, situations that perturb endothelial function and/or NO• availability will critically alter caffeine antagonism of alcohol-induced cerebrovascular constriction without significantly disrupting endothelium-independent, alcohol-induced cerebral artery constriction itself.