The suitability of caffeinated drinks for children: a systematic review of randomised controlled trials, observational studies and expert panel guidelines

Caffeine intake and its association with nutrition, sleep, and physical activity among schoolchildren in the United Arab Emirates: a national cross-sectional study

PURPOSE

Recent surveys indicate a significant increase in total caffeine intake among schoolchildren. Limited research has been published concerning the total intake of caffeine among schoolchildren in the Middle East and Gulf Cooperation Council (GCC) countries, including the UAE.

METHODS

This cross-sectional survey estimated the total caffeine intake from foods and beverages among 10,275 schoolchildren in the UAE. Caffeine intakes were related to the European Food Safety Authority's level of no safety concern (3.0 mg/kg BW) and level of effects on sleep (1.4 mg/kg BW).

RESULTS

More than half (56.2%) of the students consumed more than 100 mg (the upper limit allowed) of caffeine from dietary sources. High intake of caffeine (> 100 mg/day) was significantly associated (p = 0.001) with reduced sleep duration, difficulty falling asleep, infrequent exercising, using smart devices for more than 2 h a day, getting a lower GPA, skipping breakfast, eating fewer servings of vegetables than recommended, frequent consumption of fast food and more frequent snack consumption.

CONCLUSION

Excessive intake of caffeine from different dietary sources coexists with unhealthy dietary and lifestyle behaviors and sleep problems. Tailoring educational programs and intervention strategies is warranted to correct the unhealthy intake of caffeine and the associated unhealthy dietary and lifestyle behaviors among schoolchildren in the UAE.

Consumption of energy drinks by children and young people: a systematic review examining evidence of physical effects and consumer attitudes

OBJECTIVE

To update an earlier review, published in 2016, on the health and other outcomes associated with children and young people's consumption of energy drinks (EDs).

STUDY DESIGN

Review article.

SYSTEMATIC REVIEW

Systematic searches of nine databases (ASSIA, CINAHL, Cochrane Library, DARE, Embase, ERIC, MEDLINE, PsycINFO and Web of Science) retrieved original articles reporting the effects of EDs experienced by children and young people up to the age of 21 years. Searches were restricted by publication dates (January 2016 to July 2022) and language (English). Studies assessed as being weak were excluded from the review. Included studies underwent narrative synthesis.

RESULTS

A total of 57 studies were included. Boys consumed EDs more than girls. Many studies reported a strong positive association between ED consumption and smoking, alcohol use, binge drinking, other substance use and the intentions to initiate these behaviours. Sensation-seeking and delinquent behaviours were positively associated with ED consumption, as were short sleep duration, poor sleep quality and low academic performance. Additional health effects noted in the updated review included increased risk of suicide, psychological distress, attention-deficit hyperactivity disorder symptoms, depressive and panic behaviours, allergic diseases, insulin resistance, dental caries and erosive tooth wear.

CONCLUSIONS

This review adds to the growing evidence that ED consumption by children and young people is associated with numerous adverse physical and mental health outcomes. Where feasible and ethical, additional longitudinal studies are required to ascertain causality. The precautionary principle should be considered in regulatory policy and restriction of ED sales to this population.

PROSPERO REGISTRATION

CRD42021255484.

Consumption and effects of caffeinated energy drinks in young people: an overview of systematic reviews and secondary analysis of UK data to inform policy

BACKGROUND

This overview and analysis of UK datasets was commissioned by the UK government to address concerns about children's consumption of caffeinated energy drinks and their effects on health and behaviour.

METHODS

We searched nine databases for systematic reviews, published between 2013 and July 2021, in English, assessing caffeinated energy drink consumption by people under 18 years old (children). Two reviewers rated or checked risk of bias using AMSTAR2, and extracted and synthesised findings. We searched the UK Data Service for country-representative datasets, reporting children's energy-drink consumption, and conducted bivariate or latent class analyses.

RESULTS

For the overview, we included 15 systematic reviews; six reported drinking prevalence and 14 reported associations between drinking and health or behaviour. AMSTAR2 ratings were low or critically low. Worldwide, across reviews, from 13% to 67% of children had consumed energy drinks in the past year. Only two of the 74 studies in the reviews were UK-based. For the dataset analysis, we identified and included five UK cross-sectional datasets, and found that 3% to 32% of children, across UK countries, consumed energy drinks weekly, with no difference by ethnicity. Frequent drinking (5 or more days per week) was associated with low psychological, physical, educational and overall well-being. Evidence from reviews and datasets suggested that boys drank more than girls, and drinking was associated with more headaches, sleep problems, alcohol use, smoking, irritability, and school exclusion. GRADE (Grading of Recommendations, Assessment, Development and Evaluation) assessment suggests that the evidence is weak.

CONCLUSIONS

Weak evidence suggests that up to a third of children in the UK consume caffeinated energy drinks weekly; and drinking 5 or more days per week is associated with some health and behaviour problems. Most of the evidence is from surveys, making it impossible to distinguish cause from effect. Randomised controlled trials are unlikely to be ethical; longitudinal studies could provide stronger evidence.

PROSPERO REGISTRATIONS

CRD42018096292 - no deviations. CRD42018110498 - one deviation - a latent class analysis was conducted.

Energy Drink Consumption among Adolescents Attending Schools in Lubumbashi, Democratic Republic of Congo

BACKGROUND

The consumption of energy drinks (EDs) is increasing in the general population, but little is known about the consumption of EDs among pupils in Africa. This study was designed to assess the consumption of EDs among pupils between 10 and 17 years of age and to assess average caffeine concentrations contained in EDs sold in Lubumbashi.

METHODS

We conducted a cross-sectional survey in five schools using a standardised questionnaire taken face-to-face. Samples of locally purchased EDs were analysed by High Performance Liquid Chromatography with Ultra-Violet spectrometry (HPLC-UV).

RESULTS

Of 338 pupils (54% girls), 63% reported having consumed at least one ED in the last week and 34% drank at least one ED a day. The cheapest ED was the most widely consumed. Among pupils having consumed at least one ED in the last week, 79% reported consuming it for refreshment and 15% to get energy. For those who reported not consuming EDs, 40% reported that their parents or teachers forbade them to drink EDs. Some (14%) teenagers, mainly boys, mixed ED with alcohol. The concentrations of caffeine measured in twelve brands of EDs ranged from 7.6 to 29.4 mg/100 mL (median 23.3), giving caffeine contents of 37.5 to 160 mg (median 90 mg) per can or bottle. The estimated daily intake of caffeine through EDs was between 51.3 mg and 441.3 mg among those consuming EDs regularly.

CONCLUSION

Our study convincingly demonstrates that caffeine-containing EDs are not only consumed by youngsters living in affluent societies. We documented widespread regular consumption of EDs among (pre-)adolescent schoolchildren living in Lubumbashi, a large city of the Democratic Republic of Congo (DRC). In view of the global market expansion of caffeinated EDs, it is reasonable to suspect that similar surveys in other urban areas of sub-Saharan Africa would yield similar findings. Pricing and advertising regulations and education on EDs are necessary to limit the regular consumption of EDs among adolescents.

Perspective: The Role of Beverages as a Source of Nutrients and Phytonutrients

The Dietary Guidelines for Americans (DGA) provide nutrition advice for Americans >2 y of age. The 2020-2025 DGA proposes a life stage approach, focusing on birth through older adulthood. Limited recommendations for beverages exist except for milk, 100% fruit juice, and alcohol. The goal of this article is to provide a better understanding of the role of beverages in the diet using current scientific evidence. A Medline search of observational studies, randomized controlled trials, and meta-analyses was undertaken using key beverage words. We highlight the role beverages can play as a part of the DGA and considered beverages not traditionally included, such as those that are phytonutrient dense. Our primary consideration for beverage consumption targeted healthy Americans aged ≥2 y. However, with the proposed expansion to the life span for the 2020-2025 DGA, we also reviewed evidence for infants and toddlers from birth to 24 mo. Examples are provided on how minor changes in beverage choices aid in meeting recommended intakes of certain nutrients. Guidance on beverage consumption may aid in development of better consumer products to meet broader dietary advice. For example, beverage products that are nutrient/phytonutrient dense and lower in sugar could be developed as alternatives to 100% juice to help meet the fruit and vegetable guidelines. Although beverages are not meant to replace foods, e.g., it is difficult to meet the requirements for vitamin E, dietary fiber, or essential fatty acids through beverages alone, beverages are important sources of nutrients and phytonutrients, phenolic acids and flavonoids in particular. When considering the micronutrients from diet alone, mean intakes of calcium (in women), potassium, and vitamins A, C, and D are below recommendations and sodium intakes are well above. Careful beverage choices could close these gaps and be considered a part of a healthy dietary pattern.

Caffeine Consumption in Children: Innocuous or Deleterious? A Systematic Review

Caffeine is the most consumed psychostimulant worldwide. Its use among children is controversial. Although it produces an increase in brain activity, it could hamper growth and development in young consumers. Therefore, the aim of this review was to recognize changes produced by caffeine in children under 12 years of age and to identify the relevant alterations and the conditions of their occurrence. A systematic review of the literature was carried out using PRISMA. Initially, 5468 articles were found from the EBSCO, ScienceDirect, PubMed, and Clarivate Analytics databases. In this review, were retained 24 published articles that met the inclusion criteria. The results obtained showed that caffeine consumption hampers children's growth and development. In contrast, it supports the activation of the central nervous system and brain energy management.

Association of frequent intake of fast foods, energy drinks, or convenience food with atopic dermatitis in adolescents

PURPOSE

Specific food consumption, besides food allergy, may aggravate atopic dermatitis (AD). However, previous reports on the association between AD and food intake in adolescents are scarce. The aim of this study was to determine the relationship between AD and specific food consumption frequency in adolescents.

METHODS

A cross-sectional analysis using data from the Korea Youth Risk Behavior Web-based Survey 2017 was performed. The frequency of food consumption in the recent-diagnosed AD group (AD diagnosed within 12 months) compared to those in the previous-diagnosed AD (AD diagnosed more than 12 months ago) or control group were investigated.

RESULTS

A total of 53,373 participants were eligible for this study. The weighted prevalence of the recent-diagnosed AD and the previous-diagnosed AD was 7.39% and 18.00%, respectively. When compared with subjects with the previous-diagnosed AD, those with the recent-diagnosed AD were significantly more likely to frequently consume fast foods (odds ratio OR 1.405; 95% CI 1.150-1.717), energy drinks (OR 1.457; 95% CI 1.175-1.807), or convenience food (OR 1.304; 95% CI 1.138-1.495). Patients of the recent-diagnosed AD were significantly more likely to frequently consume fast foods (OR 1.374; 95% CI 1.155-1.634) than the control group. The differences in the frequency of specific food consumption among groups were more pronounced in high school students than in middle school students.

CONCLUSIONS

Frequent intake of fast foods, energy drinks, and convenience food was related to the recent-diagnosed AD in adolescents. Prospective cohort and interventional studies are needed to identify causal relationships.

Energy drinks in children and adolescents: demographic data and immediate effects

Energy drinks consumption has become increasingly common in the last few years, despite evidence associating these products with vast adverse health effects. This led us to explore the phenomenon of energy drinks consumption in adolescents in the Israeli Arab population of the Nazareth area (Northern Israel), examining their awareness of risks associated with consumption of energy drinks, investigating their immediate effects on the body. Our study revealed that the consumption of energy drinks is very common in adolescents of both sexes, though more common in boys. Of 375 students who filled out the questionnaire, 206 reported that they consumed energy drinks (55%), 91 were male (44.4%), and 115 were female (55.6%). In the experimental stage of this study, we found that energy drinks significantly increased systolic blood pressure in most participants within a brief period of time after drinking.Conclusion: Given the prevalence of energy drinks consumption and their side effects, it is important to increase awareness of the risks associated with their regular use and to combat this phenomenon through the education system in schools. What is Known: • Energy drinks consumption has become popular and frequent among adolescents across the world. • The immediate effects of energy drinks in children and adolescents are poorly described. What is New: • Religious and social norms are not a barrier to ED consumption among the varied investigated population. • Our study describes the immediate effect of energy drinks during the first 2 h after consumption, revealing systolic blood pressure to be significantly increased.

Key Findings and Implications of a Recent Systematic Review of the Potential Adverse Effects of Caffeine Consumption in Healthy Adults, Pregnant Women, Adolescents, and Children

In 2016⁻2017, we conducted and published a systematic review on caffeine safety that set out to determine whether conclusions that were presented in the heavily cited Health Canada assessment, remain supported by more recent data. To that end, we reviewed data from 380 studies published between June 2001 and June 2015, which were identified from an initial batch of over 5000 articles through a stringent search and evaluation process. In the current paper, we use plain language to summarize our process and findings, with the intent of sharing additional context for broader reach to the general public. We addressed whether caffeine doses previously determined not to be associated with adverse effects by Health Canada (400 mg/day for healthy adults, 300 mg/day for pregnant women, 2.5 mg/kg body weight/day for adolescents and children, and 10 g/day for acute effects) remain appropriate for five outcome areas (acute toxicity, cardiovascular toxicity, bone & calcium effects, behavior, and development and reproduction) in healthy adults, pregnant women, adolescents, and children. We used a weight-of-evidence approach to draw conclusions for each of the five outcomes, as well as more specific endpoints within those outcomes, which considered study quality, consistency, level of adversity, and magnitude of response. In general, updated evidence confirms the levels of intake that were put forth by Health Canada in 2003 as not being associated with any adverse health effects, and our results support a shift in caffeine research from healthy to sensitive populations.

The negative impact of sugar-sweetened beverages on children's health: an update of the literature

While sugar sweetened beverage (SSB) consumption has declined in the last 15 years, consumption of SSBs is still high among children and adolescents. This research synthesis updates a prior review on this topic and examines the evidence regarding the various health impacts of SSBs on children's health (overweight/obesity, insulin resistance, dental caries, and caffeine-related effects). We searched PubMed, CAB Abstracts and PAIS International to identify cross-sectional, longitudinal and intervention studies examining the health impacts of SSBs in children published after January 1, 2007. We also searched reference lists of relevant articles. Overall, most studies found consistent evidence for the negative impact of SSBs on children's health, with the strongest support for overweight/obesity risk and dental caries, and emerging evidence for insulin resistance and caffeine-related effects. The majority of evidence was cross-sectional highlighting the need for more longitudinal and intervention studies to address this research question. There is substantial evidence that SSBs increase the risk of overweight/obesity and dental caries and developing evidence for the negative impact of SSBs on insulin resistance and caffeine-related effects. The vast majority of literature supports the idea that a reduction in SSB consumption would improve children's health.

Behavioural correlates of energy drink consumption among adolescents: A review of the literature

Despite regulatory measures on the labelling of energy drinks (EDs), their consumption among adolescents continues to grow in popularity, but teachers increasingly report significant behavioural concerns among students who disclose habitual ED consumption. A review of papers published between January 2010 and October 2016 was undertaken to determine whether an association between adverse behaviour and consumption of ED exists. Findings indicate that ED consumption among adolescents is associated with alcohol and substance use, risky behaviours and psychological states including sensation seeking, depression and anxiety symptoms. ED consumption impacts negatively on executive functions and increases hyperactivity/inattention symptoms among adolescents. An inverse association between ED consumption and sleep duration exists. The findings highlight the need for greater awareness of the potential risk of ED consumption among adolescents.

The Safety of Ingested Caffeine: A Comprehensive Review

Caffeine is the most widely consumed psychoactive drug in the world. Natural sources of caffeine include coffee, tea, and chocolate. Synthetic caffeine is also added to products to promote arousal, alertness, energy, and elevated mood. Over the past decade, the introduction of new caffeine-containing food products, as well as changes in consumption patterns of the more traditional sources of caffeine, has increased scrutiny by health authorities and regulatory bodies about the overall consumption of caffeine and its potential cumulative effects on behavior and physiology. Of particular concern is the rate of caffeine intake among populations potentially vulnerable to the negative effects of caffeine consumption: pregnant and lactating women, children and adolescents, young adults, and people with underlying heart or other health conditions, such as mental illness. Here, we review the research into the safety and safe doses of ingested caffeine in healthy and in vulnerable populations. We report that, for healthy adults, caffeine consumption is relatively safe, but that for some vulnerable populations, caffeine consumption could be harmful, including impairments in cardiovascular function, sleep, and substance use. We also identified several gaps in the literature on which we based recommendations for the future of caffeine research.

Regular energy drink consumption is associated with the risk of health and behavioural problems in adolescents

Consumption of energy drinks has become popular and frequent among adolescents across Europe. Previous research showed that regular consumption of these drinks was associated with several health and behavioural problems. The aim of the present study was to determine the socio-demographic groups at risk for regular energy drink consumption and to explore the association of regular energy drinks consumption with health and behavioural problems and negative school experiences in adolescents. Data from the Health Behaviour in School-aged Children Study conducted in 2014 in Slovakia were analysed. We assessed socio-demographic characteristics, energy drink consumption, health and behavioural problems and negative school experiences based on self-reports from 8977 adolescents aged 11-15 years (mean age/standard deviation 13/1.33; 50.0% boys). The prevalence of regular energy drink consumption in the present sample was 20.6% (95%CI: 20%-21%). Regular energy drink consumption was more frequent among boys and older adolescents. Adolescents with a medium-level family affluence were less likely to drink energy drinks regularly. Adolescents who consumed energy drinks regularly had more health and behavioural problems and negative school experiences.

CONCLUSION

Adolescents drinking energy drinks are at risk of a wide range of negative outcomes and should be specifically addressed by preventive interventions. What is Known • Energy drink consumption has become popular and frequent among adolescents across Europe. • There is growing evidence that energy drink consumption is related to negative social, emotional and health outcomes, but only a few studies have explored this relationship in adolescents. What is New • Regular energy drink consumption was more frequent among boys and adolescents reporting low family affluence and increased with age. • Adolescents reporting regular energy drink consumption were in higher risk to suffer from health and behavioural problems and negative school experiences.

Peri-pubertal high caffeine exposure increases ovarian estradiol production in immature rats

Chronic caffeine consumption exerts a negligible effect on the reproductive organs of normal adult females, but it is not known whether this is also true for children and adolescents. Here, we investigated the effects of high caffeine exposure on sexual maturation and ovarian estradiol production in immature female rats. Immature female SD rats were divided into controls and caffeine groups fed 120 and 180mg/kg/day for 4 or 8 weeks. There was a significant delay in vaginal opening in the caffeine-fed groups. In addition, serum estradiol levels were elevated in the caffeine-fed animals after 2 and 4 weeks of exposure. Estradiol secretion as well as aromatase expression also increased significantly in the ovarian cells in response to caffeine. These results demonstrate that peripubertal exposure to high caffeine increases estradiol production in the ovary; this may disturb the coordinated regulation of the hypothalamo-pituitary-ovarian axis, thereby interfering with sexual maturation.

[Nutritional supplements in sports - sense, nonsense or hazard?]

The excessive sale of dietary supplements (DSs) has become a global multi-billion market as more and more people turn to DSs for a healthy lifestyle or for aesthetic reasons. DSs are also increasingly popular among athletes; 50-85% of recreational and 35-100% of competitive athletes report taking DSs, the latter more regularly. Unless pathological deficiencies are detected, the intake of DSs for recreational athletes is not recommended. While it may be advisable for competitive athletes to supplement their diet with certain macronutrients (proteins and carbohydrates), many micronutrients (vitamins, minerals) as well as allegedly performance enhancing DSs may only show minimal impact under specific conditions and for certain sports. However, most products lack proof of their effectiveness. In some cases, DSs may even have negative effects and reduce performance. Furthermore, competitive athletes should be aware of the fact that DSs may lead to positive doping tests, as they bear the risk of being contaminated with banned substances, or components may be banned substances themselves. Every single case of taking DSs should therefore be critically assessed and discussed with experts prior to use. DSs cannot replace a balanced diet and hard practice.

Caffeine consumption patterns and determinants among adolescents in Serbia

BACKGROUND

The number of adolescents who use caffeine is constantly increasing. As juvenile age is vulnerable, it is reasonable to expect that they will differently perceive reason and react to caffeine use than adults, and be more prone to unwanted physiological and psychological consequences of its consumption.

AIM

Analysis of the scope and pattern of caffeine consumption among adolescents in Serbia.

STUDY DESIGN

The cross-sectional survey was implemented in the study population of 191 Serbian adolescents during 2010.

RESULTS

The median daily intake of caffeine was 95.6 mg. The major source of caffeine was brewed coffee, and the most common reasons for caffeine intake were leisure, peer influence, or habit. Only 57.6% of the subjects were aware that caffeine is present in consumed beverages. Sex affected the pattern, but not the overall level, of caffeine consumption. No association between caffeine consumption and smoking status, frequency of caffeine use in the family, or negative personal experience with caffeine effects was observed.

CONCLUSION

Our investigation provides first and rather detailed insight into caffeine-containing beverage consumption scope and pattern among Serbian adolescents. For accurate estimation and analysis of caffeine intake in this population, randomized studies with prospective longitudinal design, caffeine content measurement, and more subjects involved are warranted.

Consumption of energy drinks by children and young people: a rapid review examining evidence of physical effects and consumer attitudes

OBJECTIVE

To examine patterns of energy drink consumption by children and young people, attitudes towards these drinks, and any associations with health or other outcomes.

DESIGN

Rapid evidence assessment and narrative synthesis.

DATA SOURCES

9 electronic bibliographic databases, reference lists of relevant studies and searches of the internet.

RESULTS

A total of 410 studies were located, with 46 meeting the inclusion criteria. The majority employed a cross-sectional design, involved participants aged 11-18 years, and were conducted in North America or Europe. Consumption of energy drinks by children and young people was found to be patterned by gender, with boys consuming more than girls, and also by activity levels, with the highest consumption observed in the most and least sedentary individuals. Several studies identified a strong, positive association between the use of energy drinks and higher odds of health-damaging behaviours, as well as physical health symptoms such as headaches, stomach aches, hyperactivity and insomnia. There was some evidence of a dose-response effect. 2 experimental studies involving small numbers of junior athletes demonstrated a positive impact on limited aspects of sports performance. 3 themes emerged from the qualitative studies: reasons for use; influences on use; and perceived efficacy and impact. Taste and energy-seeking were identified as key drivers, and branding and marketing were highlighted as major influences on young people's consumption choices. Awareness of possible negative effects was low.

CONCLUSIONS

There is growing evidence that consumption of energy drinks is associated with a range of adverse outcomes and risk behaviours in terms of children's health and well-being. However, taste, brand loyalty and perceived positive effects combine to ensure their popularity with young consumers. More research is needed to explore the short-term and long-term impacts in all spheres, including health, behaviour and education.

TRIAL REGISTRATION NUMBER

CRD42014010192.

Adolescent caffeine consumption increases adulthood anxiety-related behavior and modifies neuroendocrine signaling

Caffeine is a commonly used psychoactive substance and consumption by children and adolescents continues to rise. Here, we examine the lasting effects of adolescent caffeine consumption on anxiety-related behaviors and several neuroendocrine measures in adulthood. Adolescent male Sprague-Dawley rats consumed caffeine (0.3g/L) for 28 consecutive days from postnatal day 28 (P28) to P55. Age-matched control rats consumed water. Behavioral testing for anxiety-related behavior began in adulthood (P62) 7 days after removal of caffeine. Adolescent caffeine consumption enhanced anxiety-related behavior in an open field, social interaction test, and elevated plus maze. Similar caffeine consumption in adult rats did not alter anxiety-related behavior after caffeine removal. Characterization of neuroendocrine measures was next assessed to determine whether the changes in anxiety were associated with modifications in the HPA axis. Blood plasma levels of corticosterone (CORT) were assessed throughout the caffeine consumption procedure in adolescent rats. Adolescent caffeine consumption elevated plasma CORT 24h after initiation of caffeine consumption that normalized over the course of the 28-day consumption procedure. CORT levels were also elevated 24h after caffeine removal and remained elevated for 7 days. Despite elevated basal CORT in adult rats that consumed caffeine during adolescence, the adrenocorticotropic hormone (ACTH) and CORT response to placement on an elevated pedestal (a mild stressor) was significantly blunted. Lastly, we assessed changes in basal and stress-induced c-fos and corticotropin-releasing factor (Crf) mRNA expression in brain tissue collected at 7 days withdrawal from adolescent caffeine. Adolescent caffeine consumption increased basal c-fos mRNA in the paraventricular nucleus of the hypothalamus. Adolescent caffeine consumption had no other effects on the basal or stress-induced c-fos mRNA changes. Caffeine consumption during adolescence increased basal Crf mRNA in the central nucleus of the amygdala, but no additional effects of stress or caffeine consumption were observed in other brain regions. Together these findings suggest that adolescent caffeine consumption may increase vulnerability to psychiatric disorders including anxiety-related disorders, and this vulnerability may result from dysregulation of the neuroendocrine stress response system.

Energy drink consumption, health complaints and late bedtime among young adolescents

OBJECTIVES

Energy drinks contain large amounts of caffeine. Their effects on adolescent well-being are poorly known. We examined the relationship of energy drink consumption with health complaints and late bedtime among 13-year-olds.

METHODS

A classroom survey was conducted on all 7th graders in the Helsinki metropolitan region, Finland (73 % responded; n = 9446). Logistic regression analysis and structural equation modeling (SEM) were used.

RESULTS

The prevalence of health complaints increased as energy drink consumption increased from non-consumers to several times/day. Late bedtime (≥11 PM) increased correspondingly. Those consuming energy drinks several times/day exhibited increased odds of experiencing daily health complaints compared with non-consumers: headache OR (adjusted) = 4.6 (2.8-7.7), sleeping problems OR = 3.6 (2.2-5.8), irritation OR = 4.1 (2.7-6.1), tiredness/fatigue OR = 3.7 (2.4-5.7), and late bedtime OR = 7.8 (5.7-10.9). In SEM, energy drink consumption had a direct effect on health complaints and late bedtime and an indirect effect on health complaints via late bedtime.

CONCLUSIONS

Energy drinks, late bedtime, and health complaints form a behavior pattern that is worth considering in schools, home and clinical settings when adolescents complain about headaches, problems with sleeping and corresponding symptoms.

Acute consumption of a caffeinated energy drink enhances aspects of performance in sprint swimmers

This study investigated the effect of a caffeinated energy drink on various aspects of performance in sprint swimmers. In a randomised and counterbalanced order, fourteen male sprint swimmers performed two acute experimental trials after the ingestion of a caffeinated energy drink (3 mg/kg) or after the ingestion of the same energy drink without caffeine (0 mg/kg; placebo). After 60 min of ingestion of the beverages, the swimmers performed a countermovement jump, a maximal handgrip test, a 50 m simulated competition and a 45 s swim at maximal intensity in a swim ergometer. A blood sample was withdrawn 1 min after the completion of the ergometer test. In comparison with the placebo drink, the intake of the caffeinated energy drink increased the height in the countermovement jump (49.4 (SD 5.3) v. 50.9 (SD 5.2) cm, respectively; P<0.05) and maximal force during the handgrip test with the right hand (481 (SD 49) v. 498 (SD 43) N; P<0.05). Furthermore, the caffeinated energy drink reduced the time needed to complete the 50 m simulated swimming competition (27.8 (SD 3.4) v. 27.5 (SD 3.2) s; P<0.05), and it increased peak power (273 (SD 55) v. 303 (SD 49) W; P <0.05) and blood lactate concentration (11.0 (SD 2.0) v. 11.7 (SD 2.1) mM; P<0.05) during the ergometer test. The caffeinated energy drink did not modify the prevalence of insomnia (7 v. 7%), muscle pain (36 v. 36%) or headache (0 v. 7%) during the hours following its ingestion (P>0.05). A caffeinated energy drink increased some aspects of swimming performance in competitive sprinters, whereas the side effects derived from the intake of this beverage were marginal at this dosage.