Effects of caffeine on human health

Substitution of sugar-sweetened beverages with other beverage alternatives: a review of long-term health outcomes

BACKGROUND

Excessive consumption of sugar-sweetened beverages (SSBs) has become an intractable public health concern worldwide, making investigation of healthy beverage alternatives for SSBs imperative.

AIM

To summarize the available evidence on the effects of replacing SSBs with beverage alternatives on long-term health outcomes.

METHOD

We systematically retrieved studies from six electronic databases from inception to November 2013. Prospective cohort studies and randomized controlled trials (RCTs) examining the effects of substituting beverage alternatives for SSBs on long-term health outcomes in both children and adults were included. The quality of included studies was assessed using the Scottish Intercollegiate Guidelines Network 50 methodology checklists.

RESULTS

Six cohort studies and four RCTs were included in the systematic review with the quality rating ranging from acceptable to high. Evidence from both cohort studies and RCTs showed substitution of SSBs by various beverage alternatives was associated with long-term lower energy intake and lower weight gain. However, evidence was insufficient to draw conclusions regarding the effect of beverage substitution on other health outcomes, and which beverage alternative is the best choice.

CONCLUSIONS

Although studies on this topic are sparse, the available evidence suggests a potential beneficial effect on body weight outcomes when SSBs are replaced by water or low-calorie beverages. Further studies in this area are warranted to fully understand the long-term health implications of beverage substitutions.

Maternal total caffeine intake, mainly from Japanese and Chinese tea, during pregnancy was associated with risk of preterm birth: the Osaka Maternal and Child Health Study

The relation of maternal caffeine intake with birth outcomes is still inconclusive and has not been examined in Japan, where the sources of caffeine intake are different from those in Western countries. We hypothesized that maternal consumption of total caffeine and culture-specific major sources of caffeine would be associated with birth outcomes among Japanese pregnant. The study subjects were 858 Japanese women who delivered singleton infants. Maternal diet during pregnancy was assessed using a validated, self-administered diet history questionnaire. Birth outcomes considered were low birth weight (LBW; <2500 g), preterm birth (PTB; <37 weeks of gestation), and small for gestational age (SGA; <10th percentile). The main caffeine sources were Japanese and Chinese tea (73.5%), coffee (14.3%), black tea (6.6%), and soft drinks (3.5%). After controlling for confounders, maternal total caffeine intake during pregnancy was significantly associated with an increased risk of PTB (odds ratio per 100 mg/d caffeine increase, 1.28; 95% confidence interval, 1.03-1.58; P for trend = .03). However, no evident relationships were observed between total caffeine intake and risk of LBW or SGA. As for caffeine sources, higher Japanese and Chinese tea consumption was associated with an increased risk of PTB (odds ratio per 1 cup/d increase, 1.14; 95% confidence interval, 1.00-1.30; P for trend = .04), but not LBW or SGA. There were no associations between consumption of the other beverages examined and birth outcomes. In conclusion, this prospective birth cohort in Japan suggests that higher maternal total caffeine intake, mainly in the form of Japanese and Chinese tea, during pregnancy is associated with a greater risk of PTB.

Perceptions about Energy Drinks are Associated with Energy Drink Intake among U.S. Youth

Purpose.

Energy drinks are growing in popularity among youth because of their stimulant properties. However, they can increase blood pressure and are associated with serious consequences such as cardiac arrest. This study examined the associations between energy drink perceptions and energy drink consumption among youth.

Design.

The design was a cross-sectional study using the YouthStyles Survey 2011.

Setting.

The online survey was administered at home.

Subjects.

Subjects were youths aged 12 to 17 years in the summer of 2011 (n = 779).

Measures.

Energy drink consumption, perceptions about energy drinks, and sociodemographic and behavioral variables were measured.

Analysis.

Chi-square and multivariable logistic regression analyses were used.

Results.

Overall, 9% of youth drank energy drinks, 19.5% agreed that energy drinks are safe drinks for teens, and 12.5% agreed that energy drinks are a type of sports drink. The proportion of youth consuming energy drinks once per week or more was highest among youth aged 16 to 17 years and among those who are physically active three to six times a week. The odds for drinking energy drinks once per week or more was higher among youth who agreed that energy drinks are safe drinks for teens (odds ratios [OR] = 7.7, 95% confidence intervals [CI] = 3.6, 16.4) and among those who agreed that energy drinks are a type of sports drink (OR = 5.0, 95% CI = 2.4, 10.7).

Conclusions.

These findings suggest that many youth may be unaware or misinformed about the potential health effects and nutritional content of energy drinks. Efforts to improve education among youth about the potential adverse effects of consuming energy drinks are needed.

In vitro fertilization embryo development from caffeine-treated murine sperm

Purpose

To evaluate the effect of long-term caffeine administration on murine sperm and subsequent in vitro fertilization (IVF).

Methods

Male mice were injected with various doses (0, 0.2 and 1.0 mg/mouse/day) of caffeine for 1 month. After sperm collection, the IVF rate and embryo development to the blastocyst stage were evaluated.

Results

The mean body weight significantly decreased in the 1.0 mg/day treatment group compared to the control group (P < 0.01). Testicular weight and histological features did not differ, and total blood testosterone was no different in spite of the difference between 0.2 and 1.0 mg/day of caffeine. The IVF rate differed significantly between the control group [100/105 (95.2 %)] and 0.2 mg/day group [106/121 (87.6 %)] (P < 0.05). Furthermore, blastocyst formation was significantly and dose-dependently lower with higher caffeine levels: control group: 85/100 (85.0 %); 0.2 mg/day group: 84/106 (79.2 %) (P < 0.05); 1.0 mg/day group: 64/102 (62.7 %) (P < 0.001).

Conclusions

Caffeine treatment affected body weight of male mice. However, testicular weight, histological features and total blood testosterone concentration were not statistically different. In addition, following IVF using sperm from these mice, blastocyst formation decreased in a dose-dependent manner. These findings suggest that embryo development from oocytes fertilized with sperm from caffeine-administered male mice is negatively affected.

Caffeine and headache: specific remarks

Caffeine is the most widely used psychostimulant worldwide. Excessive caffeine consumption induces a series of both acute and chronic biological and physiological changes that may give rise to cognitive decline, depression, fatigue, insomnia, cardiovascular changes, and headache. Chronic consumption of caffeine promotes a pro-nociceptive state of cortical hyperexcitability that can intensify a primary headache or trigger a headache due to excessive analgesic use. This review offers an in-depth analysis of the physiological mechanisms of caffeine and its relationship with headache.

Caffeine protects against alcohol-induced liver fibrosis by dampening the cAMP/PKA/CREB pathway in rat hepatic stellate cells

Alcoholic liver fibrosis (ALF) is characterized by hyperplasia of extracellular matrix under long-term alcohol stimulation. Hepatic stellate cell (HSC) activation plays an important role in promoting hepatic fibrogenesis. Caffeine, as the main active component of coffee and tea, was widely consumed in daily life. It was always a thought that caffeine can reduce the probability of suffering from liver diseases. In this study, we attempt to validate the hypothesis that caffeine inhibits activation of HSCs which were isolated from rat ALF model. The rats were gavaged by ethanol to establish ALF model and then treated with different concentrations of caffeine or colchicine. Serum was collected to measure the contents of serum alanine aminotransferase (ALT), aspartate transaminase (AST), hyaluronic acid (HA), laminin (LN), N-terminal peptide of type III procollagen (PIIINP) and type IV collagen (CIV). Then liver tissues were obtained for hematoxylin-eosin staining and Sirius-red staining. Others were treated through liver perfusion to isolate primary rat HSCs. Interestingly, we found that caffeine significantly decreased ALT, AST, HA, LN, PIIINP and CIV levels and reversed liver fibrosis in rat ALF models. Results of immunohistochemistry, real-time PCR and western blot indicated that caffeine could reduce fibrosis and inhibit cAMP/PKA/CREB signal pathway in HSC. Caffeine has a preventive effect on ALF. The mechanism may be interpreted that caffeine inhibits the cAMP/PKA/CREB signal pathway through adenosine A2A receptors in HSC.

Osteogenic potential of osteoblasts from neonatal rats born to mothers treated with caffeine throughout pregnancy

BACKGROUND

Caffeine is an active alkaloid that can cause damage to bones in formation during prenatal life into adulthood. This compound can pass across the placenta and into the mother's milk, causing a reduction in bone formation, growth and mass. The objective of this study was to examine the osteogenic potential of osteoblasts extracted from neonatal rats born to mothers treated with caffeine throughout pregnancy.

METHODS

Twenty-four adult Wistar rats were randomly divided into four groups, consisting of one control group and three groups that were treated with 25, 50, or 100 mg/kg of caffeine by an oral-gastric probe throughout the duration of the experimental period (pregnancy). At birth, three puppies from each dam in each group were euthanized, and osteoblasts were extracted from the calvaria of these pups for in vitro testing.

RESULTS

The osteoblasts extracted from the pups of rats that received 50 mg/kg caffeine during pregnancy exhibited increased expression of osteocalcin, osteopontin, sialoprotein, runx-2, alkaline phosphatase and type I collagen transcripts, resulting in increased synthesis of mineralization nodules.

CONCLUSIONS

Neonates from rats treated with 50 mg/kg caffeine during pregnancy contained osteoblasts with a higher osteogenic potential characterized by increased expression of osteocalcin, osteopontin, sialoprotein, runx-2, alkaline phosphatase and type I collagen and increased synthesis of mineralization nodules.

Coffee, tea, and caffeine consumption and risk of epithelial ovarian cancer and borderline ovarian tumors: Results from a Danish case-control study

BACKGROUND

Epidemiological studies that have investigated the association between coffee, tea and caffeine consumption and ovarian cancer risk have produced conflicting results. Furthermore, only few studies have examined the role of coffee and tea consumption separately for borderline ovarian tumors. By use of data from a large Danish population-based case-control study, we examined the risk of ovarian tumors associated with coffee, tea, and caffeine consumption with a particular focus on characterizing risks by tumor behavior and histology.

MATERIAL AND METHODS

From 1995 through 1999, we included 267 women with ovarian cancer, 115 women with borderline ovarian tumors and 911 randomly selected control women. All women completed a beverage frequency questionnaire with detailed information on coffee and tea consumption. Analyses were performed using multiple logistic regression models.

RESULTS

Both coffee (OR = 0.90; 95% CI 0.84-0.97 per cup/day) and total caffeine consumption from coffee and tea combined (OR = 0.93; 95% CI 0.88-0.98 per 100 mg/day) decreased the risk of ovarian cancer. These associations were significant only for the serous and "other" subtypes of ovarian cancer. No relation between tea consumption and ovarian cancer risk was observed. The risk estimates for borderline ovarian tumors resembled those observed for ovarian cancer, but did not reach statistical significance.

CONCLUSIONS

Our results indicate that coffee consumption and total caffeine consumption from coffee and tea combined is associated with a modest decreased risk of ovarian cancer. However, more biological studies are needed to identify bioactive chemical compounds in coffee that potentially could affect ovarian cancer development.

Caffeine improves reaction time, vigilance and logical reasoning during extended periods with restricted opportunities for sleep

RATIONALE

Various occupational groups are required to maintain optimal physical and cognitive function during overnight periods of wakefulness, often with less than optimal sleep. Strategies are required to help mitigate the impairments in cognitive function to help sustain workplace safety and productivity.

OBJECTIVES

To test the effectiveness of repeated 200 mg doses of caffeine on cognitive function and live-fire marksmanship with soldiers during three successive nights of sustained wakefulness followed by 4-h afternoon sleep periods.

METHODS

Twenty Special Forces personnel (28.6 ± 4.7 years, 177.6 ± 7.5 cm and 81.2 ± 8.0 kg) were randomly assigned to receive four 200-mg doses of caffeine (n = 10) or placebo (n = 10) during the late evening and early morning hours during three successive days. An afternoon 4-h sleep period followed. The psychomotor (PVT) and field (FVT) vigilance, logical reasoning (LRT) tests and a vigilance monitor assessed cognitive function throughout the study. Live-fire marksmanship requiring friend-foe discrimination was assessed.

RESULTS

Caffeine maintained speed on the PVT (p < 0.02), improved detection of events during FVT (p < 0.001), increased number of correct responses to stimuli as assessed by the vigilance monitor (p < 0.001) and increased response speed during the LRT (p < 0.001) throughout the three overnight testing periods. Live-fire marksmanship was not altered by caffeine.

CONCLUSIONS

A total daily dose of 800 mg caffeine during successive overnight periods of wakefulness is an effective strategy to maintain cognitive function when optimal sleep periods during the day are not available.

Juice and water intake in infancy and later beverage intake and adiposity: could juice be a gateway drink?

OBJECTIVES

To examine the tracking and significance of beverage consumption in infancy and childhood.

METHODS

Among 1163 children in Project Viva, we examined associations of fruit juice and water intake at 1 year (0 oz, 1-7 oz [small], 8-15 oz [medium], and ≥16 oz [large]) with juice and sugar-sweetened beverage (SSB) intake and BMI z-score during early (median 3.1 years) and mid-childhood (median 7.7 years).

RESULTS

In covariate adjusted models, juice intake at 1 year was associated with greater juice and SSB intake during early and mid-childhood and also greater adiposity. Children who drank medium and large amounts of juice at 1 year had higher BMI z-scores during both early (medium: β = 0.16 [95% CI = 0.01-0.32]; large: β = 0.28 [95% CI = 0.01-0.56]) and mid-childhood (medium: β = 0.23 [95% CI = 0.07-0.39]; large: β = 0.36 [95% CI = 0.08-0.64]). After covariate adjustment, associations between water intake at 1 year and beverage intake and adiposity later in childhood were null.

CONCLUSIONS

Higher juice intake at 1 year was associated with higher juice intake, SSB intake, and BMI z-score during early and mid-childhood. Assessing juice intake during infancy could provide clinicians with important data regarding future unhealthy beverage habits and excess adiposity during childhood.

Caffeine intake from food and beverage sources and trends among children and adolescents in the United States: review of national quantitative studies from 1999 to 2011

There is increasing concern about potential adverse effects of caffeine in children. Our understanding of caffeine intake relies on studies dating to the late 1990s. This article synthesizes information from national studies since then to describe caffeine consumption, its association with sociodemographic factors, key dietary sources including caffeine-containing energy drinks (CCEDs), and trends in caffeine intake and sources among US children. Findings from the Kanter Worldpanel (KWP) Beverage Consumption Panel and the NHANES showed that caffeine consumption prevalence was generally consistent across studies and over time; more than one-half of 2- to 5-y-olds and ∼75% of older children (>5 y) consumed caffeine. The usual intakes of caffeine were 25 and 50 mg/d for children and adolescents aged 2-11 and 12-17 y, respectively (NHANES 2007-2010). Caffeine consumption correlated with age and was higher in non-Hispanic white children. The key sources of caffeine were soda and tea as well as flavored dairy (for children aged <12 y) and coffee (for those aged ≥12 y). The frequency of CCED use varied (2-30%) depending on study setting, methods, and demographic characteristics. A statistically significant but small decline in caffeine intake was noted in children overall during the 10- to 12-y period examined; intakes remained stable among older children (≥12 y). A significant increasing trend in CCED and coffee consumption and a decline in soda intake were noted (1999-2010). In 2009-2010, 10% of 12- to 19-y-olds and 10-25% of caffeine consumers (aged 12-19 y) had intakes exceeding Canadian maximal guidelines. Continued monitoring can help better understand changes in caffeine consumption patterns of youth.

Effects of 28-days ingestion of a slow-release energy supplement versus placebo on hematological and cardiovascular measures of health

Background

Recently, slow release tablets have been developed to prolong energy release throughout the day. The efficacy of the delivery of slow-release caffeine alone is fairly well documented; however, an assessment of safety and tolerability of prolonged use of slow-release energy supplements is lacking. Therefore the objective of this study was to investigate the effect of daily ingestion of a slow-release energy supplement for 28 days on blood chemistry and resting cardiovascular measures in healthy men and women.

Methods

Forty healthy individuals (20 males, 20 females; age: 22.73 ± 3.06 years; height: 171.68 ± 10.45 cm; mass: 74.49 ± 15.51 kg; BMI: 25.08 ± 3.66 (kg • m²) ^-1) participated in this randomized, double-blind, placebo controlled study. Following a 12-hour fast, participants reported for pre-testing. Testing consisted of resting heart rate (RHR) and blood pressure (BP) measures, followed by assessment of metabolic blood chemistry, blood lipids and complete cell counts. Participants then supplemented with either Energize™ (SUPP) or placebo (PL) for 28 days. Post-testing occurred 24-hours after ingestion of the final dose and consisted of the same protocol at the same time of day as pre-testing.

Results

No significant changes in outcome measures were observed. A significant difference between groups was observed for plasma glucose concentrations; however, follow-up testing revealed that pre- to post-supplementation changes were not significant for either SUPP or PL. All variables remained within normal adult reference ranges. No adverse events were reported.

Conclusions

These findings indicate that 28 consecutive days ingestion of a slow release energy supplement containing caffeine in caffeine users is both safe and tolerable.

Can Tea Consumption be a Safe and Effective Therapy Against Diabetes Mellitus-Induced Neurodegeneration?

Diabetes mellitus (DM) is a metabolic disease that is rapidly increasing and has become a major public health problem. Type 2 DM (T2DM) is the most common type, accounting for up to 90-95% of the new diagnosed DM cases. The brain is very susceptible to glucose fluctuations and hyperglycemia-induced oxidative stress (OS). It is well known that DM and the risk of developing neurodegenerative diseases are associated. Tea, Camellia sinensis L., is one of the most consumed beverages. It contains several phytochemicals, such as polyphenols, methylxanthines (mainly caffeine) and L-theanine that are often reported to be responsible for tea's health benefits, including in brain. Tea phytochemicals have been reported to be responsible for tea's significant antidiabetic and neuroprotective properties and antioxidant potential. Epidemiological studies have shown that regular consumption of tea has positive effects on DM-caused complications and protects the brain against oxidative damage, contributing to an improvement of the cognitive function. Among the several reported benefits of tea consumption, those related with neurodegenerative diseases are of great interest. Herein, we discuss the potential beneficial effects of tea consumption and tea phytochemicals on DM and how their action can counteract the severe brain damage induced by this disease.

Effect of Caffeine Chronically Consumed During Pregnancy on Adenosine A1 and A2A Receptors Signaling in Both Maternal and Fetal Heart from Wistar Rats

Background: Caffeine is the most widely consumed psychoactive substance in the world, even during pregnancy. Its stimulatory effects are mainly due to antagonism of adenosine actions by blocking adenosine A₁ and A_2A receptors. Previous studies have shown that caffeine can cross the placenta and therefore modulate these receptors not only in the fetal brain but also in the heart. Methods: In the present work, the effect of caffeine chronically consumed during pregnancy on A₁ and A_2A receptors in Wistar rat heart, from both mothers and their fetuses, were studied using radioligand binding, Western-blotting, and adenylyl cyclase activity assays, as well as reverse transcription polymerase chain reaction. Results: Caffeine did not significantly alter A₁R neither at protein nor at gene expression level in both the maternal and fetal heart. On the contrary, A_2AR significantly decreased in the maternal heart, although mRNA was not affected. Gi and Gs proteins were also preserved. Finally, A₁R-mediated inhibition of adenylyl cyclase activity did not change in the maternal heart, but A_2AR mediated stimulation of this enzymatic activity significantly decreased according to the detected loss of this receptor. Conclusions: Opposite to the downregulation and desensitization of the A₁R/AC pathway previously reported in the brain, these results show that this pathway is not affected in rat heart after caffeine exposure during pregnancy. In addition, A_2AR is downregulated and desensitized in the maternal heart, suggesting a differential modulation of these receptor-mediated pathways by caffeine.

Disclosure of genetic information and change in dietary intake: a randomized controlled trial

BACKGROUND

Proponents of consumer genetic tests claim that the information can positively impact health behaviors and aid in chronic disease prevention. However, the effects of disclosing genetic information on dietary intake behavior are not clear.

METHODS

A double-blinded, parallel group, 2:1 online randomized controlled trial was conducted to determine the short- and long-term effects of disclosing nutrition-related genetic information for personalized nutrition on dietary intakes of caffeine, vitamin C, added sugars, and sodium. Participants were healthy men and women aged 20-35 years (n = 138). The intervention group (n = 92) received personalized DNA-based dietary advice for 12-months and the control group (n = 46) received general dietary recommendations with no genetic information for 12-months. Food frequency questionnaires were collected at baseline and 3- and 12-months after the intervention to assess dietary intakes. General linear models were used to compare changes in intakes between those receiving general dietary advice and those receiving DNA-based dietary advice.

RESULTS

Compared to the control group, no significant changes to dietary intakes of the nutrients were observed at 3-months. At 12-months, participants in the intervention group who possessed a risk version of the ACE gene, and were advised to limit their sodium intake, significantly reduced their sodium intake (mg/day) compared to the control group (-287.3 ± 114.1 vs. 129.8 ± 118.2, p = 0.008). Those who had the non-risk version of ACE did not significantly change their sodium intake compared to the control group (12-months: -244.2 ± 150.2, p = 0.11). Among those with the risk version of the ACE gene, the proportion who met the targeted recommendation of 1500 mg/day increased from 19% at baseline to 34% after 12 months (p = 0.06).

CONCLUSIONS

These findings demonstrate that disclosing genetic information for personalized nutrition results in greater changes in intake for some dietary components compared to general population-based dietary advice.

TRIAL REGISTRATION

ClinicalTrials.gov NCT01353014.

Caffeine intake in children in the United States and 10-y trends: 2001-2010

BACKGROUND

Because of the increasing concern of the potential adverse effects of caffeine intake in children, recent estimates of caffeine consumption in a representative sample of children are needed.

OBJECTIVES

We provide estimates of caffeine intake in children in absolute amounts (mg) and in relation to body weight (mg/kg) to examine the association of caffeine consumption with sociodemographic factors and describe trends in caffeine intake in children in the United States.

DESIGN

We analyzed caffeine intake in 3280 children aged 2-19 y who participated in a 24-h dietary recall as part of the NHANES, which is a nationally representative survey of the US population with a cross-sectional design, in 2009-2010. Trends over time between 2001 and 2010 were examined in 2-19-y-old children (n = 18,530). Analyses were conducted for all children and repeated for caffeine consumers.

RESULTS

In 2009-2010, 71% of US children consumed caffeine on a given day. Median caffeine intakes for 2-5-, 6-11-, and 12-19-y olds were 1.3, 4.5, and 13.6 mg, respectively, and 4.7, 9.1, and 40.6 mg, respectively, in caffeine consumers. Non-Hispanic black children had lower caffeine intake than that of non-Hispanic white counterparts. Caffeine intake correlated positively with age; this association was independent of body weight. On a given day, 10% of 12-19-y-olds exceeded the suggested maximum caffeine intake of 2.5 mg/kg by Health Canada. A significant linear trend of decline in caffeine intake (in mg or mg/kg) was noted overall for children aged 2-19 y during 2001-2010. Specifically, caffeine intake declined by 3.0 and 4.6 mg in 2-5- and 6-11-y-old caffeine consumers, respectively; no change was noted in 12-19-y-olds.

CONCLUSION

A majority of US children including preschoolers consumed caffeine. Caffeine intake was highest in 12-19-y-olds and remained stable over the 10-y study period in this age group.

Evidence and knowledge gaps for the association between energy drink use and high-risk behaviors among adolescents and young adults

Sales of energy drinks have increased rapidly since their introduction to the marketplace in the 1990s. Despite the health concerns raised about these beverages, which are often highly caffeinated, surprisingly little data are available to estimate the prevalence of their use. This review presents the results of secondary data analyses of a nationally representative data set of schoolchildren in the United States and reviews the available research on the association between energy drink use and risk-taking behaviors. Approximately one-third of the students surveyed were recent users of energy drinks, with substantial variation by age, sex, and race/ethnicity. Among the health and safety concerns related to energy drinks and their consumption is the possible potentiation of risk-taking behaviors. The review of available research reveals that, although there does appear to be a strong and consistent positive association between the use of energy drinks and risk-taking behavior, all but one of the available studies used cross-sectional designs, thereby limiting the ability to make inferences about the temporal nature of the association. Thus, more research is needed to understand the nature of this association and how energy drinks, particularly those containing caffeine, might impact adolescent health and safety, especially given the high prevalence of their use among youth.

The use of energy drinks in sport: perceived ergogenicity and side effects in male and female athletes

The use of caffeine containing energy drinks has dramatically increased in the last few years, especially in the sport context because of its reported ergogenic effect. The ingestion of low to moderate doses of caffeinated energy drinks has been associated with adverse side effects such as insomnia or increased nervousness. The aim of the present study was to assess psycho-physiological changes and the prevalence of side effects resulting from the ingestion of 3 mg caffeine/kg body mass in the form of an energy drink. In a double-blind and placebo controlled experimental design, ninety experienced and low-caffeine-consuming athletes (fifty-three male and thirty-seven female) in two different sessions were provided with an energy drink that contained 3 mg/kg of caffeine or the same decaffeinated energy drink (placebo; 0 mg/kg). At 60 min after the ingestion of the energy drink, participants completed a training session. The effects of ingestion of these beverages on psycho-physiological variables during exercise and the rate of adverse side effects were measured using questionnaires. The caffeinated energy drink increased self-perceived muscle power during exercise compared with the placebo beverage (6·41 (sd1·7)v.5·66 (sd1·51);P= 0·001). Moreover, the energy drink produced a higher prevalence of side effects such as insomnia (31·2v.10·4 %;P< 0·001), nervousness (13·2v.0 %;P= 0·002) and activeness (16·9v.3·9 %;P= 0·007) than the placebo energy drink. There were no sex differences in the incidence of side effects (P>0·05). The ingestion of an energy drink with 3 mg/kg of caffeine increased the prevalence of side effects. The presence of these side effects was similar between male and female participants.

Coffee and health

Most people start their day with a cup of coffee. Many people would also finish their daily work with coffee. As such, coffee drinking is an important part of modern daily life. It has been told that coffee is a driving force for humans to develop science, because it has an alerting effect on the human brain. However, some people report experiencing irregular heartbeat or headaches and are thus reluctant to drink coffee, which suggests individual variation to coffee intolerance. The aim of this review is to briefly summarize the effects of coffee on human health.

Association of psychologic and nonpsychologic factors with primary dysmenorrhea

Background:

Primary dysmenorrhea seems to be one the most common gynecologic condition in women of childbearing age.

Objectives:

The aim of this research was to evaluate psychologic and nonpsychologic risk factors of primary dysmenorrhea.

Materials and Methods:

A cross-sectional study was conducted on medical sciences students of Babol University of Medical Sciences. In this study, 180 females with dysmenorrhea and 180 females without dysmenorrhea were enrolled. Psychological risk factors were evaluated in four domains including affect, social support, personality, and alexithymia. Four questionnaires were used to assessed aforementioned domains, namely, Social Support Questionnaire (SSQ), depression, anxiety, stress (DAS-21), 20-item Toronto Alexithymia Scale (TAS-20), and NEO-Five Factor Inventory of Personality (NEO-FFI). In addition, nonpsychologic factors were evaluated in three domains including demographic characteristics, habits, and gynecologic factors. Data were analyzed using the χ2 test and multiple logistic regression analysis.

Results:

The strongest predictor of primary dysmenorrhea was low social support (OR = 4.25; 95% CI, 2.43-7.41). Risk of dysmenorrhea was approximately 3.3 times higher in women with alexithymia (OR = 3.26; 95% CI, 1.88-5.62), 3.1 times higher in women with menstrual bleeding duration ≥ 7 days (OR = 3.06; 95% CI, 1.73-5.41), 2.5 times higher in women with a neurotic character (OR = 2.53; 95% CI, 1.42-4.50), 2.4 times higher in women with a family history of dysmenorrhea (OR = 2.43; 95% CI, 1.42-4.50), and twice higher in women with high caffeine intake (OR = 1.97; 95% CI, 1.09-3.59).

Conclusions:

Low social support, alexithymia, neuroticism trait, long menstrual bleeding, family history of dysmenorrhea, and high-caffeine diet are important risk factors for women with primary dysmenorrhea. This study recommended considering psychologic factors as an adjuvant to medical risks in evaluation and treatment of primary dysmenorrhea.

Caffeine induces cytoskeletal changes and cell death in H1299 cells

Caffeine is the most common natural neuroactive substance around the world. The exact mechanism of the anticancer effects of caffeine is not clear, especially in the contexts of the cytoskeletal changes. It is known that caffeine exerts an effect on cell cycle, cell proliferation, radiosensivity of cells, and also induces cell death. The aim of the study was to determine the effect of 10 and 20 mM L−1 caffeine on the major cytoskeletal proteins in non-small lung cancer cell line H1299. Caffeine treatment induced abnormalities in morphology and ultrastructure of cells. Moreover, the fluorescence studies showed changes in organization of vimentin, β-tubulin, lamin A/C and F-actin, which were attributed to the induction of cell death. The results also demonstrated that caffeine induced formation of two cell populations: giant, mono- or multinucleated cells, with the phenotype of mitotic catastrophe and shrunken cells with condensation of chromatin, typical of apoptosis. This study for the first time shows the effect of caffeine on the cytoskeleton of H1299 cell line. In conclusion, a high-dose caffeine treatment induces apoptotic cell death and makes it a powerful anticancer agent that should be considered for the treatment of non-small cell lung cancer.

Energy drink consumption and impact on caffeine risk

The impact of caffeine from energy drinks occurs against a background exposure from naturally occurring caffeine (coffee, tea, cocoa and foods containing these ingredients) and caffeinated beverages (kola-type soft drinks). Background caffeine exposure, excluding energy drinks, was assessed for six New Zealand population groups aged 15 years and over (n = 4503) by combining concentration data for 53 caffeine-containing foods with consumption information from the 2008/09 New Zealand Adult Nutrition Survey (ANS). Caffeine exposure for those who consumed energy drinks (n = 138) was similarly assessed, with inclusion of energy drinks. Forty-seven energy drink products were identified on the New Zealand market in 2010. Product volumes ranged from 30 to 600 ml per unit, resulting in exposures of 10-300 mg caffeine per retail unit consumed. A small percentage, 3.1%, of New Zealanders reported consuming energy drinks, with most energy drink consumers (110/138) drinking one serving per 24 h. The maximum number of energy drinks consumed per 24 h was 14 (total caffeine of 390 mg). A high degree of brand loyalty was evident. Since only a minor proportion of New Zealanders reported consuming energy drinks, a greater number of New Zealanders exceeded a potentially adverse effect level (AEL) of 3 mg kg(-1) bw day(-1) for caffeine from caffeine-containing foods than from energy drinks. Energy drink consumption is not a risk at a population level because of the low prevalence of consumption. At an individual level, however, teenagers, adults (20-64 years) and females (16-44 years) were more likely to exceed the AEL by consuming energy drinks in combination with caffeine-containing foods.

Standard addition strip for quantitative electrostatic spray ionization mass spectrometry analysis: determination of caffeine in drinks

Standard addition strips were prepared for the quantitative determination of caffeine in different beverages by electrostatic spray ionization mass spectrometry (ESTASI-MS). The gist of this approach is to dry spots of caffeine solutions with different concentrations on a polymer strip, then to deposit a drop of sample mixed with an internal standard, here theobromine on each spot and to measure the mass spectrometry signals of caffeine and theobromine by ESTASI-MS. This strip approach is very convenient and provides quantitative analyses as accurate as the classical standard addition method by MS or liquid chromatography.

Vaccines against drugs of abuse: where are we now?

Drug addiction is a serious problem worldwide. One therapy being investigated is vaccines against drugs of abuse. The antibodies elicited against the drug can take up the drug and prevent it from reaching the reward centers in the brain. Few such vaccines have entered clinical trials, but research is going on apace. Many studies are very promising and more clinical trials should be coming out in the near future.

Energy drink usage among university students in a Caribbean country: Patterns of use and adverse effects

Objective: There has been little inquiry addressing whether or not concerns about adverse effects of energy drink usage are relevant in the Caribbean. This survey investigated energy drink usage and adverse consequences among tertiary level students in Trinidad and Tobago.

Methods: A cross-sectional survey of 1994 students from eight institutions was conducted using a de novo questionnaire based on findings from a focus group of students. Chi-squared analyses and logistic regression were used to assess relationships between energy drink usage, adverse effects and other factors affecting energy drink use, and to verify predictors of energy drink use.

Results: Prevalence of use was 86%; 38% were current users. Males were more likely to use, used more frequently and at an earlier age. Energy drinks were used most commonly to increase energy (50%), combat sleepiness (45%) and enhance academic performance (40%), and occurred during sports (23%) and mixed with alcohol (22.2%). The majority (79.6%) consumed one energy drink per sitting; 62.2% experienced adverse effects, most commonly restlessness (22%), jolt and crash (17.1%) and tachycardia (16.6%). Awareness of adverse effects was associated with no use (p = 0.004), but adverse effects were not a deterrent to continued use.

Conclusion: Energy drink usage is prevalent among students. The use is not excessive, but associated with high rates of adverse effects and occurs in potentially dangerous situations like during exercise and with alcohol. There is a need to educate students about the potential adverse effects of energy drinks.

Caffeine Use Disorder: A Review of the Evidence and Future Implications

The latest edition of the Diagnostic and Statistical Manual (DSM-5) has introduced new provisions for caffeine-related disorders. Caffeine Withdrawal is now an officially recognized diagnosis, and criteria for caffeine use disorder have been proposed for additional study. caffeine use disorder is intended to be characterized by cognitive, behavioral, and physiological symptoms indicative of caffeine use despite significant caffeine-related problems, similar to other Substance Use Disorders. However, since nonproblematic caffeine use is so common and widespread, it may be difficult for some health professionals to accept that caffeine use can result in the same types of pathological behaviors caused by alcohol, cocaine, opiates, or other drugs of abuse. Yet there is evidence that some individuals are psychologically and physiologically dependent on caffeine, although the prevalence and severity of these problems is unknown. This article reviews the recent changes to the DSM, the concerns regarding these changes, and some potential impacts these changes could have on caffeine consumers.

Adenosine receptor antagonists including caffeine alter fetal brain development in mice

Consumption of certain substances during pregnancy can interfere with brain development, leading to deleterious long-term neurological and cognitive impairments in offspring. To test whether modulators of adenosine receptors affect neural development, we exposed mouse dams to a subtype-selective adenosine type 2A receptor (A2AR) antagonist or to caffeine, a naturally occurring adenosine receptor antagonist, during pregnancy and lactation. We observed delayed migration and insertion of γ-aminobutyric acid (GABA) neurons into the hippocampal circuitry during the first postnatal week in offspring of dams treated with the A2AR antagonist or caffeine. This was associated with increased neuronal network excitability and increased susceptibility to seizures in response to a seizure-inducing agent. Adult offspring of mouse dams exposed to A2AR antagonists during pregnancy and lactation displayed loss of hippocampal GABA neurons and some cognitive deficits. These results demonstrate that exposure to A2AR antagonists including caffeine during pregnancy and lactation in rodents may have adverse effects on the neural development of their offspring.

Evidence-based recommendations for natural bodybuilding contest preparation: nutrition and supplementation

The popularity of natural bodybuilding is increasing; however, evidence-based recommendations for it are lacking. This paper reviewed the scientific literature relevant to competition preparation on nutrition and supplementation, resulting in the following recommendations. Caloric intake should be set at a level that results in bodyweight losses of approximately 0.5 to 1%/wk to maximize muscle retention. Within this caloric intake, most but not all bodybuilders will respond best to consuming 2.3-3.1 g/kg of lean body mass per day of protein, 15-30% of calories from fat, and the reminder of calories from carbohydrate. Eating three to six meals per day with a meal containing 0.4-0.5 g/kg bodyweight of protein prior and subsequent to resistance training likely maximizes any theoretical benefits of nutrient timing and frequency. However, alterations in nutrient timing and frequency appear to have little effect on fat loss or lean mass retention. Among popular supplements, creatine monohydrate, caffeine and beta-alanine appear to have beneficial effects relevant to contest preparation, however others do not or warrant further study. The practice of dehydration and electrolyte manipulation in the final days and hours prior to competition can be dangerous, and may not improve appearance. Increasing carbohydrate intake at the end of preparation has a theoretical rationale to improve appearance, however it is understudied. Thus, if carbohydrate loading is pursued it should be practiced prior to competition and its benefit assessed individually. Finally, competitors should be aware of the increased risk of developing eating and body image disorders in aesthetic sport and therefore should have access to the appropriate mental health professionals.

Religious Involvement and Health-Related Behaviors Among Black Seventh-Day Adventists in Canada

Background. Most studies that involve Black Seventh-Day Adventists (SDAs) have been conducted in the United States. We sought to examine the association between religious involvement and lifestyle practices among Black SDAs in Canada. Method. A convenience sample of 509 Black SDA church members 18 years and older completed a self-administered questionnaire, assessing religious involvement and seven lifestyle practices promoted by the SDA church: diet, physical activity, water intake, exposure to sunlight, alcohol use, caffeine and tobacco use, and rest. Results. Compliance with lifestyle practices ranged from a low of 10% meeting fitness guidelines to a high of 99% abstaining from tobacco products. Religious involvement and lifestyle were positively related ( rs = .11, p < .05). Multivariate analyses indicated that private religious practice ( β = .16, p =.003), importance of the health principles ( β = .17, p = .003), and acceptance of health principles ( β = .65, p = .00001) significantly predicted the number of behaviors practiced. Conclusion. Greater religious involvement is associated with positive lifestyle practices but is not an independent predictor of lifestyle practices for Black Canadian SDAs.

Consumption of organic and functional food. A matter of well-being and health?

Health is an important motivation for the consumption of both organic and functional foods. The aim of this study was to clarify to what extent the consumption of organic and functional foods are characterized by a healthier lifestyle and a higher level of well-being. Moreover, the influence of social desirability on the respondents' response behavior was of interest and was also analyzed. Well-being and health was measured in a sample of 555 German consumers at two levels: the cognitive-emotional and the behavioral level. The results show that although health is an important aspect for both functional food and organic food consumption, these two forms of consumption were influenced by different understandings of health: organic food consumption is influenced by an overall holistic healthy lifestyle including a healthy diet and sport, while functional food consumption is characterized by small "adjustments" to lifestyle to enhance health and to increase psychological well-being. An overlap between the consumption of organic and functional food was also observed. This study provides information which enables a better characterization of the consumption of functional food and organic food in terms of well-being and health.

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.

Caffeine in tea Camellia sinensis--content, absorption, benefits and risks of consumption

Therapeutic properties of tea Camellia sinensis are of particular interest since it has been consumed for ages and was always regarded as safe beverage. Tea is most popular beverage in the world because of its attractive aroma, exceptional taste, health promoting and pharmaceutical potential. Current results showed that antioxidative, antibacterial and other health effects are attributed to its caffeine content and caffeine - polyphenols interactions. An overview is given on caffeine content in different tea leaves beverage. Special attention is drawn to caffeine physiological effect on human organism. Controversies concerning the possible caffeine influence on human physical and psychological health are briefly summarized and presented.

[Caffeine in analgesics--myth or medicine?]

Caffeine as an analgesic adiuvant has been discussed for many years. In a recent Cochrane review based on 19 studies with a total of 7238 patients, caffeine enhanced the efficacy of paracetamol, ibuprofen or aspirin with a number needed to treat (NNT) of about 16, comparable to the effect of doubling the dose of the primary analgesic, reported by other authors. Analgesia by caffeine is best explained by antagonism at adenosine receptors. Recent studies confirmed a favourable tolerability profile of caffeine when consumed in "normal" quantities (e.g. 300 mg or about 3 cups of coffee per day), including possible cardiovascular risks, effects on bone density, and exposure in pregnancy. Beneficial effects are known,e.g.,in Parkinson's disease and liver cirrhosis and fibrosis. Caffeine remains an analgesic adiuvant with a favourable risk-benefit balance.

Psychostimulants and cognition: a continuum of behavioral and cognitive activation

Psychostimulants such as cocaine have been used as performance enhancers throughout recorded history. Although psychostimulants are commonly prescribed to improve attention and cognition, a great deal of literature has described their ability to induce cognitive deficits, as well as addiction. How can a single drug class be known to produce both cognitive enhancement and impairment? Properties of the particular stimulant drug itself and individual differences between users have both been suggested to dictate the outcome of stimulant use. A more parsimonious alternative, which we endorse, is that dose is the critical determining factor in cognitive effects of stimulant drugs. Herein, we review several popular stimulants (cocaine, amphetamine, methylphenidate, modafinil, and caffeine), outlining their history of use, mechanism of action, and use and abuse today. One common graphic depiction of the cognitive effects of psychostimulants is an inverted U-shaped dose-effect curve. Moderate arousal is beneficial to cognition, whereas too much activation leads to cognitive impairment. In parallel to this schematic, we propose a continuum of psychostimulant activation that covers the transition from one drug effect to another as stimulant intake is increased. Low doses of stimulants effect increased arousal, attention, and cognitive enhancement; moderate doses can lead to feelings of euphoria and power, as well as addiction and cognitive impairment; and very high doses lead to psychosis and circulatory collapse. This continuum helps account for the seemingly disparate effects of stimulant drugs, with the same drug being associated with cognitive enhancement and impairment.

The effects of caffeine, nicotine, ethanol, and tetrahydrocannabinol on exercise performance

Caffeine, nicotine, ethanol and tetrahydrocannabinol (THC) are among the most prevalent and culturally accepted drugs in western society. For example, in Europe and North America up to 90% of the adult population drinks coffee daily and, although less prevalent, the other drugs are also used extensively by the population. Smoked tobacco, excessive alcohol consumption and marijuana (cannabis) smoking are addictive and exhibit adverse health effects. These drugs are not only common in the general population, but have also made their way into elite sports because of their purported performance-altering potential. Only one of the drugs (i.e., caffeine) has enough scientific evidence indicating an ergogenic effect. There is some preliminary evidence for nicotine as an ergogenic aid, but further study is required; cannabis and alcohol can exhibit ergogenic potential under specific circumstances but are in general believed to be ergolytic for sports performance. These drugs are currently (THC, ethanol) or have been (caffeine) on the prohibited list of the World Anti-Doping Agency or are being monitored (nicotine) due to their potential ergogenic or ergolytic effects. The aim of this brief review is to evaluate the effects of caffeine, nicotine, ethanol and THC by: 1) examining evidence supporting the ergogenic or ergolytic effects; 2) providing an overview of the mechanism(s) of action and physiological effects; and 3) where appropriate, reviewing their impact as performance-altering aids used in recreational and elite sports.

Intrauterine metabolic programming alteration increased susceptibility to non-alcoholic adult fatty liver disease in prenatal caffeine-exposed rat offspring

An increase in susceptibility to metabolic syndromes (MetS) in rat offspring that experienced prenatal caffeine exposure (PCE) has been previously demonstrated. The present study aimed to clarify this increased susceptibility and elucidate the mechanism of foetal origin that causes or contributes to adult non-alcoholic fatty liver disease (NAFLD) as a result of PCE. Based on the results from both foetal and adult studies of rats that experienced PCE (120 mg/kgd), the foetal weight and serum triglyceride levels decreased significantly and hepatocellular ultrastructure was altered. Foetal livers exhibited inhibited insulin-like growth factor-1 (IGF-1), enhanced lipogenesis and reduced lipid output. In adult female offspring of PCE+lab chow, lipid synthesis, oxidation and output were enhanced, whereas lipogenesis was inhibited in their male conterparters. Furthermore, in adult offspring of PCE+ high-fat diet, catch-up growth appeared obvious with enhanced hepatic IGF-1, especially in females. Both males and females showed increased lipid synthesis and reduced output, which were accompanied by elevated serum triglyceride. Severe NAFLD appeared with higher Kleiner scores. Gluconeogenesis was continuously enhanced in females. Therefore, increased susceptibility to diet-induced NAFLD in PCE offspring was confirmed, and it appears to be mediated by intrauterine glucose and alterations in lipid metabolic programming. This altered programming enhanced foetal hepatic lipogenesis and reduced lipid output in utero, which continued into the postnatal phase and reappeared in adulthood with the introduction of a high-fat diet, thereby aggravating hepatic lipid accumulation and causing NAFLD.