Coffee acutely increases sympathetic nerve activity and blood pressure independently of caffeine content: role of habitual versus nonhabitual drinking

Relationship between human serum metabolites and angina pectoris: a Mendelian randomization study

PURPOSE

We aimed to explore the causal relationship between human serum metabolites and angina pectoris.

METHODS

This study used two-sample Mendelian randomization (MR) analysis to assess the association between 486 serum metabolites and angina pectoris. The analytical methods employed to reduce study bias included inverse variance weighted, MR-Egger, and weighted median method. A comprehensive sensitivity analysis was performed using the leave-one-out method, while instrumental variable pleiotropy was tested with MR-Pleiotropy RESidual Sum and Outlier. Metabolic pathways of angina-associated metabolites were analysed on the MetaboAnalyst metabolomics analysis tool platform.

RESULTS

In this study, 42 serum metabolites were found to be strongly associated with angina pectoris. They mainly belonged to seven groups: amino acids, carbohydrates, cofactors and vitamins, lipids, nucleotides, unknown metabolites, and exogenous substances. Pipecolate posed the highest risk for the development of angina pectoris among the 42 serum metabolites. The main metabolic pathways associated with angina pectoris were glycine, serine, threonine metabolism, primary bile acid biosynthesis, and caffeine metabolism.

CONCLUSION

We identified 25 high-risk and 17 protective human serum metabolites associated with angina pectoris. Their associated major metabolic pathways were also determined. The serum metabolite pipecolate was significantly and positively correlated with the risk of angina pectoris. This finding may serve as a valuable reference for testing serum markers associated with angina pectoris.

Fasting for 48 h induced similar glucose intolerance in both sexes despite greater perceived stress and decreased estradiol levels in females

PURPOSE

The purpose of this study was to compare the effects of fasting for 48 h on the evoked insulin and glucose responses in males and females, and to explore factors such as stress and estrogen levels that might influence these responses.

METHODS

Healthy, nonobese male (n = 14) and female (n = 14) subjects underwent 48-h fasting trial. Changes in glucose tolerance and insulin levels in response to the oral glucose tolerance test, subjectively perceived stress and catecholamine concentrations were measured in all participants. Estrogen levels were also measured in the female participants during the 48-h fast.

RESULTS

Glucose area under the curve (AUC) values increased similarly in both sexes after 48-h fasting (P < 0.05), but females displayed a greater rise in insulin AUC values than males (P < 0.05). Fasting increased plasma epinephrine concentrations in both sexes (P < 0.05), whereas plasma norepinephrine concentrations and subjective stress increased only in females (P < 0.05). Plasma 17-β-estradiol concentrations in females decreased after fasting (P < 0.05).

CONCLUSION

Fasting for 48 h induced a similar glucose intolerance in females and males, despite decreased 17-β-estradiol levels and greater psychological and physiological stress in females. These differences represent a plausible explanation for the gender-based differences observed in insulin responses.

TRIAL REGISTRATION

Retrospectively registered on ClinicalTrials.gov (NCT05545943) in September 19, 2022.

Using caffeine as a chemical means to induce flow states

Flow is an intrinsically rewarding state characterised by positive affect and total task absorption. Because cognitive and physical performance are optimal in flow, chemical means to facilitate this state are appealing. Caffeine, a non-selective adenosine receptor antagonist, has been emphasized as a potential flow-inducer. Thus, we review the psychological and biological effects of caffeine that, conceptually, enhance flow. Caffeine may facilitate flow through various effects, including: i) upregulation of dopamine D1/D2 receptor affinity in reward-associated brain areas, leading to greater energetic arousal and 'wanting'; ii) protection of dopaminergic neurons; iii) increases in norepinephrine release and alertness, which offset sleep-deprivation and hypoarousal; iv) heightening of parasympathetic high frequency heart rate variability, resulting in improved cortical stress appraisal, v) modification of striatal endocannabinoid-CB1 receptor-signalling, leading to enhanced stress tolerance; and vi) changes in brain network activity in favour of executive function and flow. We also discuss the application of caffeine to treat attention deficit hyperactivity disorder and caveats. We hope to inspire studies assessing the use of caffeine to induce flow.

Association between dietary patterns and cardiovascular diseases: A review

Cardiovascular disease (CVD), especially atherosclerosis, is the primary cause of global deaths. It accounts for millions of deaths annually. Even a small reduction in CVD through preventive treatment can have a substantial impact. Dietary patterns and substances are strongly linked to chronic diseases such as atherosclerosis, hypertension, heart failure, and type 2 diabetes. An unhealthy diet could lead to traditional risk factors such as LDL levels, TG levels, diabetes, and high blood pressure while accelerating atherosclerosis progression. Recent research has shown the potential of dietary interventions to prevent and treat cardiovascular disease, particularly through healthy dietary patterns such as the Mediterranean diet or DASH. In 2016, the World Health Organization (WHO) and the US Centers for Disease Control and Prevention (CDC) launched a new initiative aimed at enhancing the prevention and control of cardiovascular disease (CVD) by improving the management of CVD in primary care, including the optimization of dietary patterns. Here, this review summarizes several large cohort researches about the effects of dietary patterns on atherosclerosis, refines dietary components, and outlines some typical anti-atherosclerosis dietary agents. Finally, this review discusses recent mechanisms by which dietary interventions affect atherosclerosis progression.

Coffee and Microbiota: A Narrative Review

Coffee is one of the most widely consumed beverages in the world, which has important repercussions on the health of the individual, mainly because of certain compounds it contains. Coffee consumption exerts significant influences on the entire body, including the gastrointestinal tract, where a central role is played by the gut microbiota. Dysbiosis in the gut microbiota is implicated in the occurrence of numerous diseases, and knowledge of the microbiota has proven to be of fundamental importance for the development of new therapeutic strategies. In this narrative review, we thoroughly investigated the link between coffee consumption and its effects on the gut microbiota and the ensuing consequences on human health. We have selected the most significant articles published on this very interesting link, with the aim of elucidating the latest evidence about the relationship between coffee consumption, its repercussions on the composition of the gut microbiota, and human health. Based on the various studies carried out in both humans and animal models, it has emerged that coffee consumption is associated with changes in the gut microbiota, although further research is needed to understand more about this link and the repercussions for the whole organism.

Post-occlusive reactive hyperemia in habituated caffeine users: Effects of abstaining versus consuming typical doses

BACKGROUND

Post-occlusive reactive hyperemia (PORH) typically requires caffeine abstinence. For habitual users, it is unknown if abstinence affects PORH.

OBJECTIVE

Compare PORH after habitual users consume or abstain from caffeine.

METHODS

On separate visits (within-subject), PORH was measured in 30 participants without abstinence from typical caffeine doses (CAFF) and with abstinence (ABS). Measurements included baseline and peak hyperemic velocity, tissue saturation index slopes during ischemia (Slope 1) and following cuff deflation (Slope 2), resting arterial occlusion pressure (AOP), heart rate (HR), systolic (SBP), and diastolic (DBP) blood pressure. All variables were compared using Bayesian paired t-tests. BF10 = likelihood of alternative vs null. Results are mean±SD.

RESULTS

Comparing baseline velocity (cm/s) between CAFF (9.3±4.8) and ABS (7.5±4.9) yielded anecdotal evidence (BF10 = 1.0). Peak hyperemic velocity (cm/s) was similar (CAFF = 77.3±16.7; ABS = 77.6±19.0, BF10 = 0.20). For slopes (TSI% /s), CAFF Slope 1 = -0.11±0.04 and Slope 2 = 1.9±0.46 were similar (both BF10≤0.20) to ABS Slope 1 = -0.12±0.03 and Slope 2 = 1.8±0.42. SBP and DBP (mmHg) were both similar (CAFF SBP = 116.0±9.8, DBP = 69.6±5.8; ABS SBP = 115.5±10.7, DBP = 69.5±5.4; both BF10≤0.22). Comparing AOP (mmHg) (CAFF = 146.6±15.0; ABS = 143.0±16.4) yielded anecdotal evidence (BF10 = 0.46). HR (bpm) was similar (CAFF = 66.5±12.3; ABS = 66.9±13.0; BF10 = 0.20).

CONCLUSIONS

In habitual users, consuming or abstaining from typical caffeine doses does not appear to affect post-occlusive reactive hyperemia.

Effects of aerobic exercise on ambulatory blood pressure responses to acute partial sleep deprivation: impact of chronotype and sleep quality

Blood pressure (BP) follows a circadian rhythm intertwined with the sleep-wake cycle. Acute partial sleep deprivation (PSD; sleep ≤ 6 h) can increase BP, associated with increased cardiovascular risk. Acute exercise can reduce BP for up to 24 h, a phenomenon termed postexercise hypotension. The present study tested whether aerobic exercise could mitigate the augmented 24-h ambulatory BP caused by acute PSD. Twenty-four young otherwise healthy adults (22 ± 3 yr; 14 females; self-reported chronotypes: 6 early/10 intermediate/8 late; Pittsburgh sleep quality index: 17 good/7 poor sleepers) completed a randomized crossover trial in which, on different days, they slept normally (2300-0700), restricted sleep [0330-0700 (PSD)], and cycled for 50 min (70-80% predicted heart rate maximum) before PSD. Ambulatory BP was assessed every 30 min until 2100 the next day. Acute PSD increased 24-h systolic BP (control 117 ± 9 mmHg, PSD 122 ± 9 mmHg; P < 0.001) and prior exercise attenuated (exercise + PSD 120 ± 9 mmHg; P = 0.04 vs. PSD) but did not fully reverse this response (exercise + PSD, P = 0.02 vs. control). Subgroup analysis revealed that the 24-h systolic BP reduction following exercise was specific to late types (PSD 119 ± 7 vs. exercise + PSD 116 ± 6 mmHg; P < 0.05). Overall, habitual sleep quality was negatively correlated with the change in daytime systolic BP following PSD (r = -0.56, P < 0.01). These findings suggest that the ability of aerobic cycling exercise to counteract the hemodynamic effects of acute PSD in young adults may be dependent on chronotype and that habitual sleep quality can predict the daytime BP response to acute PSD.NEW & NOTEWORTHY We demonstrate that cycling exercise attenuates, but does not fully reverse, the augmented 24-h ambulatory blood pressure (BP) response caused by acute partial sleep deprivation (PSD). This response was primarily observed in late chronotypes. Furthermore, daytime BP after acute PSD is related to habitual sleep quality, with better sleepers being more prone to BP elevations. This suggests that habitual sleeping habits can influence BP responses to acute PSD and their interactions with prior cycling exercise.

Immediate effect of caffeine on sympathetic nerve activity: why coffee is safe? A single-centre crossover study

PURPOSES

Habitual coffee drinking is ubiquitous and generally considered to be safe despite its transient hypertensive effect. Our purpose was to determine the role of the sympathetic nervous system in the hypertensive response.

METHODS

In a single-centre crossover study, medical caregivers were studied after consumption of standard coffee (espresso), water and decaffeinated coffee (decaff) given in random order at least 1 month apart. Plasma caffeine levels, mean arterial pressure, heart rate, total peripheral resistance and muscle sympathetic activity were recorded. Baroreflex activity was assessed using burst incidence and RR interval changes to spontaneous blood pressure fluctuations.

RESULTS

A total of 16 subjects (mean [± standard error] age 34.4 ± 2 years; 44% female) were recruited to the study. Three agents were studied in ten subjects, and two agents were studied in six subjects. Over a 120-min period following the consumption of standard coffee, mean (± SE) plasma caffeine levels increased from 2.4 ± 0.8 to 21.0 ± 4 µmol/L and arterial pressure increased to 103 ± 1 mmHg compared to water (101 ± 1 mmHg; p = 0.066) and decaff (100 ± 1 mmHg; p = 0.016). Peripheral resistance in the same period following coffee increased to 120 ± 4% of the baseline level compared to water (107 ± 4; p = 0.01) and decaff (109 ± 4; p = 0.02). Heart rate was lower after both coffee and decaff consumption: 62 ± 1 bpm compared to water (64 bpm; p = 0.01 and p = 0.02, respectively). Cardio-vagal baroreflex activity remained stable after coffee, but sympathetic activity decreased, with burst frequency of 96 ± 3% versus water (106 ± 3%; p = 0.04) and decaff (112 ± 3%; p = 0.001) despite a fall in baroreflex activity from - 2.2 ± 0.1 to - 1.8 ± 0.1 bursts/100 beats/mmHg, compared to water (p = 0.009) and decaff (p = 0.004).

CONCLUSION

The hypertensive response to coffee is secondary to peripheral vasoconstriction but this is not mediated by increased sympathetic nerve activity. These results may explain why habitual coffee drinking is safe.

Is Coffee and Tea a Threat or Ally to Cardiovascular Health?

Tea and coffee have become ingrained in our daily lives and have become the most widely consumed drinks after water. Their effects vary on an individual basis depending upon the amount of daily consumption, genetic polymorphisms, and the presence of comorbidities. Non-habitual individuals experience an initial, brief increase in blood pressure due to caffeine's vasoactive effects. Caffeine also appears to be protective against arrhythmias and heart failure. Along with having a generally cardioprotective profile, they have also demonstrated to have a favorable impact on insulin resistance and reduced risk of diabetes mellitus. Physicians often practice caution and advise patients with known cardiovascular diseases to refrain from drinking caffeine; however, studies have shown that drinking two to three cups a day has either no or some beneficial effects on both patients with or without cardiac disorders like arrhythmias. This article focuses on the effects of tea and coffee on the cardiovascular system as well as the potential mechanisms involved.

Diminished baseline autonomic outflow in semantic dementia relates to left-lateralized insula atrophy

In semantic dementia (SD), asymmetric degeneration of the anterior temporal lobes is associated with loss of semantic knowledge and alterations in socioemotional behavior. There are two clinical variants of SD: semantic variant primary progressive aphasia (svPPA), which is characterized by predominant atrophy in the anterior temporal lobe and insula in the left hemisphere, and semantic behavioral variant frontotemporal dementia (sbvFTD), which is characterized by predominant atrophy in those structures in the right hemisphere. Previous studies of behavioral variant frontotemporal dementia, an associated clinical syndrome that targets the frontal lobes and anterior insula, have found impairments in baseline autonomic nervous system activity that correlate with left-lateralized frontotemporal atrophy patterns and disruptions in socioemotional functioning. Here, we evaluated whether there are similar impairments in resting autonomic nervous system activity in SD that also reflect left-lateralized atrophy and relate to diminished affiliative behavior. A total of 82 participants including 33 people with SD (20 svPPA and 13 sbvFTD) and 49 healthy older controls completed a laboratory-based assessment of respiratory sinus arrhythmia (RSA; a parasympathetic measure) and skin conductance level (SCL; a sympathetic measure) during a two-minute resting baseline period. Participants also underwent structural magnetic resonance imaging, and informants rated their current affiliative behavior on the Interpersonal Adjective Scale. Results indicated that baseline RSA and SCL were lower in SD than in healthy controls, with significant impairments present in both svPPA and sbvFTD. Voxel-based morphometry analyses revealed left-greater-than-right atrophy related to diminished parasympathetic and sympathetic outflow in SD. While left-lateralized atrophy in the mid-to-posterior insula correlated with lower RSA, left-lateralized atrophy in the ventral anterior insula correlated with lower SCL. In SD, lower baseline RSA, but not lower SCL, was associated with lower gregariousness/extraversion. Neither autonomic measure related to warmth/agreeableness, however. Through the assessment of baseline autonomic nervous system physiology, the present study contributes to expanding conceptualizations of the biological basis of socioemotional alterations in svPPA and sbvFTD.

Coffee consumption and abdominal aortic calcification among adults with and without hypertension, diabetes, and cardiovascular diseases

BACKGROUND AND AIMS

This study was performed to investigate the effect of coffee consumption on abdominal aortic calcification (AAC) among adults with and without hypertension, diabetes, and cardiovascular diseases (CVD).

METHODS AND RESULTS

A total of 2548 participants from the National Health and Nutrition Examination Survey (NHANES) 2013-2014 were included. Coffee consumption was obtained from 24-h dietary recalls. Dual-energy X-ray absorptiometry (DXA) was used to measure the severity of AAC. In the fully adjusted model, compared with non-drinkers, high coffee consumption (≥390 g/d) was associated with higher AAC scores among participants with hypertension (β = 0.72, 95% CI: 0.21-1.22), diabetes (β = 1.20, 95% CI: 0.35-2.05), and CVD (β = 2.03, 95% CI: 0.71-3.36). We did not observe such an association among participants without hypertension, diabetes, and CVD. Furthermore, decaffeinated coffee was not associated with AAC.

CONCLUSION

In conclusion, patients with hypertension, diabetes, and CVD should focus on coffee consumption, especially caffeinated coffee, to reduce the burden of AAC.

Caffeine Drug Interactions and its Clinical Implication After Acute Coronary Syndrome: A Literature Review

The hemodynamic and cardiovascular impacts of coffee and caffeine have long been controversial. However, due to the worldwide popularity of coffee and caffeinated beverages, it is essential to understand how they affect the cardiovascular system, specifically in patients with a history of acute coronary syndrome. This literature review was conducted to explore the cardiovascular effects of coffee and caffeine and their interactions with common drugs after acute coronary syndrome and percutaneous coronary intervention. The evidence suggests that moderate coffee and caffeine consumption is not associated with cardiovascular disease in healthy individuals and patients with a history of acute coronary syndrome. The interactions of coffee or caffeine with common medications after acute coronary syndrome or percutaneous coronary intervention are less studied. However, based on the current human studies in this field, the only interaction is with the protective effect of statins on cardiac ischemia.

A meta-analysis and systematic review of randomized clinical trials on the effect of coffee consumption on heart rate

CONTEXT

Resting heart rate (HR) is increasingly recognized as an indicator of disease and overall morbidity and mortality. Whether chronic coffee consumption affects resting HR is an important consideration for individual consumers as well as from a public health perspective.

OBJECTIVE

A meta-analysis of randomized controlled trials (RCTs) was conducted to examine the effectiveness of coffee consumption on resting HR.

DATA SOURCES

Original RCTs assessing the effect of coffee consumption on resting HR and published prior to March 2023 were identified by searching online databases, including PubMed, Web of Science, and Cochrane Library databases.

DATA EXTRACTION AND ANALYSIS

Data searches and extraction and risk-of-bias assessments were performed according to the Cochrane guidelines, and the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines for systematic reviews were followed. Data on study characteristics, type, and amount of coffee and net change and measurement resting HR were extracted. A random-effects or a fixed-effects model was used to estimate the pooled effect sizes. Homogeneity was determined with the Cochran Q test, and publication bias was assessed through Begg's test, Egger's test, and funnel plots.

RESULTS

A total of 6 RCTs with 11 intervention trials or arms involving 485 individuals were included. The participants were generally healthy, although some had hypertension, hypercholesterolemia, or were overweight. The trial duration ranged from 2 weeks to 24 weeks. The overall pooled analysis showed that coffee consumption resulted in a negligible increase in resting HR of 0.40 beats per minute (95% CI: -0.78 to 1.57; P = 0.506), which was statistically insignificant. Subgroup analysis of all specified categories was consistent with the overall analysis. No heterogeneity was observed among included trials (I2 = 0.0%, P = 0.756).

CONCLUSION

The results of the present meta-analysis study demonstrate that daily coffee consumption of 3 to 6 cups for a period of 2 to 24 weeks has no statistically significant effect on resting HR.

Relationship between Habitual Caffeine Consumption, Attentional Performance, and Individual Alpha Frequency during Total Sleep Deprivation

(1) Background: Caffeine is a psychostimulant that is well known to mitigate the deleterious effects of sleep debt. Our aim was to assess the effects of acute caffeine intake on cognitive vulnerability and brain activity during total sleep deprivation (TSD), taking into account habitual caffeine consumption. (2) Methods: Thirty-seven subjects were evaluated in a double-blind, crossover, total sleep deprivation protocol with caffeine or placebo treatment. Vigilant attention was evaluated every six hours during TSD using the psychomotor vigilance test (PVT) with EEG recordings. The influence of habitual caffeine consumption was analyzed by categorizing subjects into low, moderate, and high consumers. (3) Results: The PVT reaction time (RT) increased during TSD and was lower in the caffeine condition vs. the placebo condition. The RT was shorter in the low-caffeine consumers compared to moderate and high consumers, regardless of conditions and treatments. The TSD-related increase in EEG power was attenuated by acute caffeine intake independently of habitual caffeine consumption, and the individual alpha frequency (IAF) was lower in the high-consumption group. The IAF was negatively correlated with daytime sleepiness. Moreover, a correlation analysis showed that the higher the daily caffeine consumption, the higher the RT and the lower the IAF. (4) Conclusions: A high level of habitual caffeine consumption decreases attentional performance and alpha frequencies, decreasing tolerance to sleep deprivation.

Association Between Coffee Consumption and Incident Atrial Fibrillation (from the Multi-Ethnic Study of Atherosclerosis [MESA])

This study aimed to elucidate a potential dose-dependent relation between coffee intake and atrial fibrillation (AF) incidence in a multi-ethnic setting. Previous studies were comprised mainly of White populations, and an exploration of dose dependency is limited. To address these gaps, we analyzed the Multi-Ethnic Study of Atherosclerosis data, a prospective cohort study. In the primary analysis, we crudely divided patients into 3 groups: nonconsumers, 1 to 3 cups/month, and ≥1 cup/week. For the secondary analysis, we stratified the cohort into 9 groups of gradual increments for coffee consumption. A multivariable cox proportional hazards regression model was adjusted for 6 potential confounders: age, gender, smoking, hypertension, diabetes mellitus, and alcohol. Subjects who drank ≥1 cup of coffee/week had a higher incidence of AF (adjusted hazard ratio 1.40, p = 0.015) than nonconsumers. Furthermore, in the secondary analysis, there was an overall trend, albeit not consistent, of increasing adjusted hazard ratio with progressively increasing doses of coffee in the following groups: 1 to 3 cups/month, 2 to 4 cups/week, 2 to 3 cups/day and ≥6 cups/day. Notably, AF incidence was highest (9.8%) for the group consuming the most coffee, that is, ≥6 cups/day (p = 0.02). Stratification by race/ethnicity suggested the results may be driven by White and Hispanic rather than Black or Chinese-American subgroups. In conclusion, the findings suggest an association between coffee consumption and incident AF in contrast to most previous studies.

Association of caffeine intake with all-cause and cardiovascular mortality in elderly patients with hypertension

Background

Caffeine is widely consumed not only in coffee but also in soft drinks and tea. However, the long-term health effects of caffeine are still controversial, especially in people with high cardiovascular risk such as elderly patients with hypertension.

Methods

This study analyzed data from the National Health and Nutrition Examination Survey 2003-2018. Caffeine intake was calculated by two 24-h dietary recall interviews. Complex sampling-weighted multivariable Cox proportional hazards models were used to compare the hazard ratios (HRs) of all-cause and cardiovascular mortality in elderly hypertensive patients with different caffeine intake (<10, 10 to <100, 100 to <200, 200 to <300, and ≥300 mg/day).

Results

This study included 6,076 elderly hypertensive patients. The mean ± standard error follow-up duration was 6.86 ± 0.12 years. During this period, a total of 2,200 all-cause deaths occurred, of which 765 were cardiovascular deaths. Taking patients with caffeine intake < 10 mg/day as a reference, patients with moderate caffeine intake (200 to <300 mg/day) had a lower risk of all-cause (HR, 0.70 [95% CI, 0.56-0.87]) and cardiovascular (HR, 0.55 [95% CI, 0.39-0.77]) mortality. The benefit of reducing all-cause mortality risk was significant in female patients (HR, 0.65 [95% CI, 0.50-0.85]) or patients with well-controlled blood pressure (HR, 0.63 [95% CI, 0.46-0.87]), but not in male patients or patients with poorly controlled blood pressure. In addition, non-linear relationship analysis also showed that moderate caffeine intake had the lowest HRs of all-cause (Non-linear p = 0.022) and cardiovascular mortality (Non-linear p = 0.032) in the present study.

Conclusion

Moderate caffeine intake is associated with reduced risk of all-cause and cardiovascular mortality in elderly hypertensive patients.

Association of Coffee, Tea, and Caffeine Consumption With All-Cause Risk and Specific Mortality for Cardiovascular Disease Patients

Aim

The aim of the study was to examine the relationship between coffee, tea, caffeine consumption and risk of all-cause death and cardiovascular disease (CVD) death in CVD population.

Methods

This cohort study included 626 CVD participants aged ≥18 years old who derived from the National Health and Nutrition Examination Surveys (NHANES) database 2003–2006. The end time of follow-up was 2015, and with a median follow-up time of 113.5 (63, 133) months. CVD death was defined as a death caused by congestive heart failure (CHF), coronary heart disease (CHD), angina pectoris, heart attack or stroke. Cox model and competitive-risk model were used to explore the relationship of coffee, tea, caffeine, decaffeinated coffee/tea on the risk of the all-cause death and CVD death for CVD population, respectively. Additionally, we explored the effect of urinary caffeine and caffeine metabolites on all-cause death.

Results

All patients were divided into survival group (n = 304), non-CVD death group (n = 223), and CVD death group (n = 99). The incidence of all-cause death and CVD death was ~51.44 and 15.81% in the study. After adjusting age, body mass index (BMI), cancer, estimated glomerular filtration rate (eGFR), energy, the history of CVD medications, carbohydrate and family income to poverty ratio (PIR), the results suggested coffee, caffeine, iced tea and hot tea consumption (≥4 cups per day) were associated with an increased risk of the all-cause death in CVD patients; while hot tea (1–3 cups per day), decaffeinated coffee/iced tea/hot tea could reduce the risk of the all-cause death. Likewise, coffee, caffeine, iced tea (≥4 cups per day), hot tea, decaffeinated iced tea/ hot tea (Always) could enhance the risk of the CVD death in CVD population. We also found that 1-methylxanthine showed a significant positive association on the risk of all-cause death in CVD population.

Conclusion

Our study indicated that higher consumption of coffee, tea and caffeine could increase the risk of all-cause and CVD death for CVD patients.

Caffeine and rheumatoid arthritis: A complicated relationship

The current ideal goal of rheumatoid arthritis (RA) management is to resolve joint and systemic inflammation by using pharmacological interventions, assuming this will correspondingly lead to overall well-being. Nonetheless, it has emerged that a substantial number of RA patients do not reach optimal disease control. Thus suggesting the holistic management of subjective symptoms might be overlooked. This poses significant medical challenges; hence the proposal of incorporating lifestyle interventions as part of a multidimensional approach. Among these aspects, both patients and physicians perceive the important role of nutrition. This review shall examine how caffeine, one of the most studied bioactive components of the most widely consumed beverages, may potentially interfere with RA management. In particular, the mechanism by which caffeine affects RA pathogenesis, as a trigger for RA onset or flare, including its influence on rheumatic drug metabolism and the most common RA comorbidities and constitutional symptoms are outlined, highlighting important knowledge gaps and unmet research needs.

Energy Drinks: Effects on Blood Pressure and Heart Rate in Children and Teenagers. A Randomized Trial

Background

The consumption of Energy Drinks (ED) is very popular among children and teenagers. While potential cardiovascular side effects of these beverages are suggested, the acute impact of ED consumption on the pediatric cardiovascular system has not been systematically examined yet. The aim of this study was to investigate the acute effects of ED consumption on blood pressure and heart rate in healthy children and teenagers.

Methods

This study was a randomized, single-blind, placebo-controlled, crossover clinical trial. On two consecutive days, the study participants were asked to consume a weight-adjusted amount of an ED (3 mg caffeine per kg of body weight) or a placebo containing a similar amount of sugar but without conventional ED ingredients. Systolic blood pressure (SBP), diastolic blood pressure (DBP) and heart rate were measured at the following time points: baseline as well as 30, 60, 120 and 240 min after beverage consumption.

Results

In total, 27 healthy children and adolescents (mean age 14.53 ± 2.40 years, 14 male) were included in the present study. Compared to placebo intake, mean SBP was demonstrated to be up to 5.23 mmHg (p < 0.0001) and mean DBP up to 3.29 mmHg (p < 0.001) increased after ED consumption. Prevalence of elevated blood pressure, stage 1 and stage 2 hypertension was higher after ED consumption. Heart rate tended to be lower after ED consumption.

Conclusions

The acute ED consumption is associated with a significantly increased SBP and DBP in healthy children and teenagers. Minors, particularly those with pre-existing health conditions, should be discouraged from drinking EDs.

Clinical Trial Registration

https://www.drks.de/drks_web/, identifier: DRKS00027580.

Nature Ambience in a Lunch Restaurant Has the Potential to Evoke Positive Emotions, Reduce Stress, and Support Healthy Food Choices and Sustainable Behavior: A Field Experiment among Finnish Customers

Laboratory experiments have indicated that exposure to restorative ambiences in food environments can lead to beneficial outcomes for consumers, but there is little evidence if this positive effect holds true in real-life consumption conditions. Therefore, the aim of this study was to analyze the effects of lunch restaurant ambience on customers’ emotional responses, stress recovery, food choices, and generation of plate waste. The expectation was that ambience inducing positive emotional responses would lead to alleviated stress, healthier food choices, and reduced plate waste. A field experiment with a baseline and two experimental ambiences (‘nature ambience’ to induce positive emotions and ‘fast food ambience’ to induce less positive emotions) including visual and auditory stimuli was conducted in a lunch restaurant for one week per ambience. Emotional responses, and objective and subjective stress were measured from a subgroup of participants (n = 32). Food choices and plate waste were measured for all customers (n = 1610–1805 depending on the study week). During ‘nature ambience’ week, customers more often chose vegetarian dishes and generated less plate waste. The results on emotional responses and stress recovery were partially in line with the expectations. The study provides real-life evidence that restaurant ambience modification could lead to beneficial consequences for customers.

Impact of energy drink versus coffee consumption on periodic repolarization dynamics: an interventional study

Purpose

Caffeinated beverages are consumed daily throughout the world. Caffeine consumption has been linked to dysfunction of the autonomic nervous system. However, the exact effects are still insufficiently understood.

Methods

Sixteen healthy individuals were included in the present non-randomized cross-over interventional study. All study subjects consumed a commercial energy drink (containing 240 mg caffeine), and in a second independent session coffee (containing 240 mg caffeine). High-resolution digital ECGs in Frank-lead configuration were recorded at baseline before consumption, and 45 min after consumption of the respective beverage. Using customized software, we assessed ECG-based biomarker periodic repolarization dynamics (PRD), which mirrors the effect of efferent cardiac sympathetic activity on the ventricular myocardium.

Results

The consumption of energy drinks resulted in an increase in PRD levels (3.64 vs. 5.85 deg²; p < 0.001). In contrast, coffee consumption did not alter PRD levels (3.47 vs 3.16 deg², p = 0.63). The heart rates remained unchanged both after coffee and after energy drink consumption. Spearman analysis showed no significant correlation between PRD changes and heart rate changes (R = 0.34, p = 0.31 for coffee, R = 0.31, p = 0.24 for energy drink).

Conclusion

Our data suggests that sympathetic activation after consumption of caffeinated beverages is independent from caffeine and might be mediated by other substances.

Trial Number: NCT04886869, 13 May 2021, retrospectively registered

Antidiarrheal Effect of 80% Methanol Extract and Fractions of the Roasted Seed of Coffea arabica Linn (Rubiaceae) in Swiss Albino Mice

BACKGROUND

Globally in 2019, diarrhea was the second leading cause of mortality in children, accounting for more than half a million under-five deaths yearly. Several societies use Coffea arabica Linn for the treatment of diarrhea. However, its use is not scientifically validated.

OBJECTIVE

The study was conducted to evaluate antidiarrheal activity of 80% methanol extract and solvent fractions of roasted seed of Coffea arabica Linn in mice.

METHODS

Coffea arabica Linn seed was roasted, milled, extracted, and fractionated using hexane, ethyl acetate, and distilled water. Castor oil-induced diarrhea, enteropooling, and motility tests were conducted. Effects on onset, number of feces, weight of feces, fluid content, volume and weight of intestinal content, and motility were evaluated by administering 100 mg/kg, 200 mg/kg, and 400 mg/kg of each extract. Negative controls received 10 ml/kg of the vehicle, and positive controls received either loperamide (3 mg/kg) or atropine (1 mg/kg). Data were analyzed using one-way ANOVA followed by Tukey's post hoc test.

RESULTS

Ethyl acetate fraction at all tested doses significantly prolonged (p < 0.05) onset of diarrhea. The number and weight of feces were also reduced significantly by crude extract and ethyl acetate fraction. Reduction in fluid content was observed at 200 mg/kg and 400 mg/kg of the crude extract (p < 0.01) and aqueous fraction (p < 0.001) as well as all tested doses of ethyl acetate fraction (p < 0.001). Similarly, the crude extract, ethyl acetate fraction, and aqueous fraction showed a significant reduction in the volume and weight of intestinal content. At 400 mg/kg, the crude extract, hexane fraction, aqueous fraction, and all doses of ethyl acetate fraction showed significant antimotility activity.

CONCLUSION

The results of this study revealed that the roasted seed of Coffea arabica Linn has antidiarrheal activity.

Multiple catechols in human plasma after drinking caffeinated or decaffeinated coffee

BACKGROUND

Coffee is one of the most frequently consumed beverages worldwide. Research on effects of coffee drinking has focused on caffeine; however, coffee contains myriad biochemicals that are chemically unrelated to caffeine, including 3,4-dihydroxyphenyl compounds (catechols) such as caffeic acid and dihydrocaffeic acid (DHCA).

OBJECTIVE

This prospective within-subjects study examined effects of drinking caffeinated or decaffeinated coffee on plasma free (unconjugated) catechols measured by liquid chromatography with series electrochemical detection (LCED) after batch alumina extraction. To confirm coffee-related chromatographic peaks represented catechols, plasma was incubated with catechol-O-methyltransferase and S-adenosylmethionine before the alumina extraction; reductions in peak heights would identify catechols.

METHODS

Ten healthy volunteers drank 2 cups each of caffeinated and decaffeinated coffee on separate days after fasting overnight. With subjects supine, blood was drawn through an intravenous catheter up to 240 min after coffee ingestion and the plasma assayed by alumina extraction followed by LCED.

RESULTS

Within 15 min of drinking coffee of either type, >20 additional peaks were noted in chromatographs from the alumina eluates. Most of the coffee-related peaks corresponded to free catechols. Plasma levels of the catecholamines epinephrine and dopamine increased with both caffeinated and decaffeinated coffee. Levels of other endogenous catechols were unaffected. Plasma DHCA increased bi-phasically, in contrast with other coffee-related free catechols.

INTERPRETATION

Drinking coffee-whether caffeinated or decaffeinated-results in the rapid appearance of numerous free catechols in the plasma. These might affect the disposition of circulating catecholamines. The bi-phasic increase in plasma DHCA is consistent with production by gut bacteria.

Coffee and Arterial Hypertension

Purpose of Review

Coffee is a very popular drink and an estimated 2.25 billion cups worldwide are consumed daily. Such popularity of coffee makes it the most consumed drink next to water. Numerous studies have shown a beneficial effect of habitual and moderate coffee consumption on the functioning of the nervous, digestive, and cardiovascular systems, as well as on kidney function. Taking into account the very high prevalence of arterial hypertension in the world (31.1% of adults), much controversy has been raised about the influence of coffee consumption on blood pressure and the risk of arterial hypertension. Moreover, there have been extensive discussions about the safety of coffee consumption for hypertensive persons.

Recent Findings

There are over 1000 chemical compounds in coffee. The best characterized of these are caffeine, chlorogenic acid, trigonelline, kahweol, cafestol, ferulic acid, and melanoidins. These compounds have bidirectional influences on blood pressure regulation. The results of numerous studies and meta-analyses indicate that moderate and habitual coffee consumption does not increase and may even reduce the risk of developing arterial hypertension. Conversely, occasional coffee consumption has hypertensinogenic effects. Moderate habitual coffee consumption in hypertensive persons does not appear to increase the risk of uncontrolled blood pressure and may even reduce the risk of death from any cause.

Summary

Moderate and habitual consumption of coffee (1-–3 cups / day) does not adversely affect blood pressure in most people, including those with arterial hypertension.

The Association Between Coffee Consumption and Nonalcoholic Fatty Liver Disease in the South Korean General Population

SCOPE

To identify the cross-sectional and prospective association between coffee consumption and nonalcoholic fatty liver disease (NAFLD) among South Korean adults.

METHODS AND RESULTS

Participants are selected from the Health Examinees study. NAFLD is defined using three non-invasive indexes: fatty liver index (FLI), hepatic steatosis index, and fibrosis-4 calculator (FIB-4). In the cross-sectional analysis, higher habitual coffee consumption is associated with a lower risk for NAFLD, define using the FLI, (men, odds ratio [OR] 0.702; women, OR 0.810) compared with non-consumers. Participants who consumed coffee with sugar and creamer also have a lower risk for NAFLD, defined using the FIB-4, compared with non-coffee-consumers (men, OR 0.739; women, OR 0.807). A prospective analysis indicated that higher coffee consumption is associated with a lower incidence of NAFLD, defined using the FLI, in men (hazard ratio, 0.706). In both men and women, a lower FIB-4 index score is associated with higher coffee consumption regardless of coffee type (all p-value <0.05).

CONCLUSIONS

 Coffee consumption of >3 cups per day has a protective effect against the development of NAFLD to a certain extent, and a negative association is found between coffee consumed with sugar and creamer and the FIB-4 index score in South Korean adults.

The Cardiovascular Benefits of Caffeinated Beverages: Real or Surreal? /"Metron Ariston - All in Moderation"

Caffeinated beverages are the most widely consumed beverages globally with coffee and tea as the two most prominent sources of caffeine. Caffeine content varies across different types of beverages. In addition to caffeine, coffee and tea have other biologically active compounds, and all may affect general and cardiovascular (CV) health. Moderate caffeine consumption (<300-400 mg/day), regardless of the source, is considered safe by both European and US Health Authorities, as it is not associated with adverse health and CV effects, while it may confer certain health benefits. There is a nonlinear association between coffee ingestion and CV risk; moderate coffee drinking is inversely significantly associated with CV risk, with the highest benefit at 2-4 cups per day, while heavy coffee drinking might confer increased risk. With regards to tea, due to a lower caffeine content per serving, its consumption is only limited by the total caffeine daily intake. Both these caffeinated beverages, coffee and tea, have additional phenolic compounds, with anti-oxidant and anti-inflammatory activities, which confer cardioprotective benefits. Of the several coffee compounds, chloroacetic acids and melanoidins offer such beneficial effects, while diterpenes may have unfavorable effects on lipids. Most of the tea ingredients (polyphenols) are cardioprotective. A major concern relates to energy drinks with their much higher caffeine content which puts individuals, especially adolescents and young adults, at high health and CV risk. All these issues are herein discussed, including pertinent studies and meta-analyses, pathogenetic mechanisms involved and relevant recommendations from health authorities.

Addition of milk to coffee beverages; the effect on functional, nutritional, and sensorial properties

To date, there exists a debate on the effect of milk added to coffee infusions/beverages concerning the nutritional quality of coffee and the functional properties of its phenolic compounds. Yet, the full nutritional quality and functional properties of a coffee beverage without a significant negative impact on its sensorial profile are highly desired by the consumers. Negative/masking, positive, and neutral effects of milk on the antioxidant activity and bioavailability of coffee phenolics (particularly, chlorogenic acids) have been reported. Some potential factors including the type and amount of milk added, type of coffee beverage, the composition of both milk (protein and fat) and coffee (phenolic compounds), preparation method, assays used to measure antioxidant properties, and sampling size may account for the various reported findings. Interactions between phenolic compounds in coffee and milk proteins could account as the main responsible aspect for the reported masking/negative impact of milk on the antioxidant activity and bioaccessibility/bioavailability of coffee bioactives. However, considering the interactions between milk components and coffee phenolics, which result in the loss of their functionality, the role of milk fat globules and the milk fat globule membrane can also be crucial, but this has not been addressed in the literature so far.HighlightsIn most cases, milk is added to the coffee beverages in several various ways.Effect of milk on the nutritional/functional properties of coffee is controversial.Enough evidence suggests negative effects of milk addition on properties of coffee.Interactions of coffee phenolics and milk proteins could account as the main aspect.The role of milk fat globules and milk fat globule membrane may also be crucial.

Association of urinary caffeine and caffeine metabolites with cardiovascular disease risk in adults

OBJECTIVES

Studies have shown that the consumption of a moderate amount of caffeine is associated with a reduced risk of cardiovascular disease (CVD) and may even be protective against CVD. The purpose of the current study was to evaluate the association between urinary caffeine and its related metabolites and CVD risk in a national representative sample of US adults.

METHODS

We analyzed cross-sectional data from the US National Health and Nutrition Examination Survey from 2009 and 2010. The associations between the levels of urinary caffeine metabolites and self-reported CVD, including congestive heart failure, coronary heart disease, angina, heart attack, and stroke, were examined separately in men and women using multivariate logistic regression models adjusted for covariates.

RESULTS

In total, 1916 participants (910 men and 1006 women) were included in the analysis. Among women, the odds ratios of CVD in the highest quartiles of 1,3-dimethylxanthine and 1,3,7-trimethylxanthine were 0.33 (95% confidence interval [CI], 0.12-0.92) and 0.35 (95% CI, 0.13-0.93), respectively, compared with the lowest quartiles. Each one-unit (µmol/L) increase in theophylline concentration was associated with a 0.24-mg/dL increase in high-density lipoprotein cholesterol in the fully adjusted model. Among men, no significant association was observed between urinary caffeine metabolites and CVD. Regarding the subtypes of CVD, compared with women in the lowest quartile for 1,3-dimethylxanthine and 1,3,7-trimethylxanthine, the odds of coronary heart disease decreased by 90% (95% CI, -99% to -11%) and 97% (95% CI, -99% to -47%), respectively, in those in the highest quartile.

CONCLUSIONS

Urinary 1,3-dimethylxanthine and 1,3,7-trimethylxanthine were significantly and inversely associated with CVDs in women. Additional studies are needed to further confirm the results of this study and explore the underlying mechanisms.<END ABSTRACT>.

Additive effects of green tea and coffee on all-cause mortality in patients with type 2 diabetes mellitus: the Fukuoka Diabetes Registry

INTRODUCTION

The impact of consuming green tea or coffee on mortality in patients with diabetes is controversial. We prospectively investigated the impact of each beverage and their combination on mortality among Japanese patients with type 2 diabetes.

RESEARCH DESIGN AND METHODS

In all, 4923 patients (2790 men, 2133 women) with type 2 diabetes (mean age, 66 years) were followed prospectively (median, 5.3 years; follow-up rate, 99.5%). We evaluated the amount of green tea and coffee consumed using self-administered questionnaires.

RESULTS

During the follow-up period, 309 participants died. The consumption of green tea, coffee, and a combination of the beverages was associated with reduced all-cause mortality. Multivariable-adjusted hazard ratios (95% CIs) for green tea were as follows: none 1.0 (referent); 0.85 (0.60-1.22) for ≤1 cup/day; 0.73 (0.51-1.03) for 2-3 cups/day; 0.60 (0.42-0.85) for ≥4 cups/day; and P for trend, 0.002. For coffee, they were: none 1.0 (referent); 0.88 (0.66-1.18) for <1 cup/day; 0.81 (0.58-1.13) for 1 cup/day; 0.59 (0.42-0.82) for ≥2 cups/day; P for trend, 0.002. With the combination they were 1.0 (referent) for no consumption of green tea and coffee; 0.49 (0.24-0.99) for 2-3 cups/day of green tea with ≥2 cups/day of coffee; 0.42 (0.20-0.88) for ≥4 cups/day of green tea with 1 cup/day of coffee; and 0.37 (0.18-0.77) for ≥4 cups/day of green tea with ≥2 cups/day of coffee.

CONCLUSIONS

Higher consumption of green tea and coffee was associated with reduced all-cause mortality: their combined effect appeared to be additive in patients with type 2 diabetes.

Assessing Autonomic Function from Electrodermal Activity and Heart Rate Variability During Cold-Pressor Test and Emotional Challenge

Standard functional assessment of autonomic nervous system (ANS) activity on cardiovascular control relies on spectral analysis of heart rate variability (HRV) series. However, difficulties in obtaining a reliable measure of sympathetic activity from HRV spectra limits the exploitation of sympatho-vagal metrics. On the other hand, measures of electrodermal activity (EDA) have been demonstrated to provide a reliable quantifier of sympathetic dynamics. In this study we propose novel indices of phasic autonomic regulation mechanisms by combining HRV and EDA correlates and thoroughly investigating their time-varying dynamics. HRV and EDA series were gathered from 26 healthy subjects during a cold-pressor test and emotional stimuli. Instantaneous linear and nonlinear (bispectral) estimates of vagal dynamics were obtained from HRV through inhomogeneous point-process models, and combined with a sensitive maker of sympathetic tone from EDA spectral power. A wavelet decomposition analysis was applied to estimate phasic components of the proposed sympatho-vagal indices. Results show significant statistical differences for the proposed indices between the cold-pressor elicitation and previous resting state. Furthermore, an accuracy of 73.08% was achieved for the automatic emotional valence recognition. The proposed nonlinear processing of phasic ANS markers brings novel insights on autonomic functioning that can be exploited in the field of affective computing and psychophysiology.

Modifiable lifestyle factors in women with Takotsubo syndrome: A case-control study

BACKGROUND

There is limited information on the relationship between modifiable lifestyle factors and Takotsubo syndrome (TS).

OBJECTIVES

To determine the association of physical activity, smoking, alcohol use, and caffeinated coffee consumption with TS.

METHODS

This case-control study enrolled women with newly diagnosed TS (n = 45), women post-myocardial infarction (MI; n = 32), and healthy women volunteers (HC; n = 30). Information on physical activity, smoking, alcohol use, and caffeinated coffee consumption was collected 1-month post-discharge for TS and MI, and 1-month post-enrollment for HC.

RESULTS

TS women reported a higher prevalence of lifetime smoking and cigarette packs/day, greater coffee consumption, and less physical activity than HC. Associations with cigarette and coffee use remained significant in adjusted models. Physical activity, smoking, and coffee consumption were similar in TS and MI women.

CONCLUSIONS

Use of psychostimulants (caffeine and cigarettes) may play a role in TS pathophysiology. These findings need to be confirmed in larger, fully powered studies.

Tolerance to Central Hypovolemia Is Greater Following Caffeinated Coffee Consumption in Habituated Users

We investigated the influence of caffeinated coffee consumption on cardiovascular responses and tolerance to central hypovolemia in individuals habituated to caffeine. Thirteen participants completed three trials, consuming caffeinated coffee, decaffeinated coffee or water before exposure to central hypovolemia via lower body negative pressure (LBNP) to pre syncope. Tolerance to central hypovolemia was quantified as cumulative stress index (CSI: LBNP level multiplied by time; mmHg × min). Prior to the consumption of caffeinated coffee, decaffeinated coffee, and water, heart rate (HR: 62 ± 10, 63 ± 9 and 61 ± 8 BPM, respectively), stroke volume (SV: 103 ± 23, 103 ± 17 and 102 ± 18 mL/beat, respectively), and total peripheral resistance (TPR: 14.2 ± 3.0, 14.0 ± 3.0, and 14.3 ± 2.7 mmHg/L/min, respectively), were not different between trials (all P > 0.05). Mean arterial pressure (MAP) increased following consumption of all drinks (Post Drink) (Caffeinated coffee: from 86 ± 8 to 97 ± 7; Decaffeinated coffee: from 88 ± 10 to 94 ± 7; and Water: from 87 ± 10 to 96 ± 6 mmHg; all P = 0.0001) but was not different between trials (P = 0.247). During LBNP, HR increased (P = 0.000) while SV decreased (P = 0.000) relative to post drink values and TPR as unchanged (P = 0.109). HR, SV, and TPR were not different between trials (all P > 0.05). MAP decreased at pre syncope in all trials (60 ± 5, 60 ± 7, and 61 ± 6 mmHg; P < 0.001). LBNP tolerance was greater following caffeinated coffee (914 ± 309 mmHg × min) relative to decaffeinated coffee and water (723 ± 336 and 769 ± 337 mmHg × min, respectively, both P < 0.05). Tolerance to central hypovolemia was greater following consumption of caffeinated coffee in habituated users.

A 2 Adenosine Receptors Mediate Whole-Body Insulin Sensitivity in a Prediabetes Animal Model: Primary Effects on Skeletal Muscle

Epidemiological studies showed that chronic caffeine intake decreased the risk of type 2 diabetes. Previously, we described that chronic caffeine intake prevents and reverses insulin resistance induced by hypercaloric diets and aging, in rats. Caffeine has several cellular mechanisms of action, being the antagonism of adenosine receptors the only attained with human coffee consumption. Here, we investigated the subtypes of adenosine receptors involved on the effects of chronic caffeine intake on insulin sensitivity and the mechanisms and sex differences behind this effect. Experiments were performed in male and female Wistar rats fed either a chow or high-sucrose (HSu) diet (35% of sucrose in drinking water) during 28 days, to induce insulin resistance. In the last 15 days of diet the animals were submitted to DPCPX (A₁ antagonist, 0.4 mg/kg), SCH58261 (A_2A antagonist, 0.5 mg/kg), or MRS1754 (A_2B antagonist, 9.5 μg/kg) administration. Insulin sensitivity, fasting glycaemia, blood pressure, catecholamines, and fat depots were assessed. Expression of A₁, A_2A, A_2B adenosine receptors and protein involved in insulin signaling pathways were evaluated in the liver, skeletal muscle, and visceral adipose tissue. UCP1 expression was measured in adipose tissue. Paradoxically, SCH58261 and MRS1754 decreased insulin sensitivity in control animals, whereas they both improved insulin response in HSu diet animals. DPCPX did not alter significantly insulin sensitivity in control or HSu animals, but reversed the increase in total and visceral fat induced by the HSu diet. In skeletal muscle, A₁, A_2A, and A_2B adenosine receptor expression were increased in HSu group, an effect that was restored by SCH58261 and MRS1754. In the liver, A₁, A_2A expression was increased in HSu group, while A_2B expression was decreased, being this last effect reversed by administration of MRS1754. In adipose tissue, A₁ and A_2A block upregulated the expression of these receptors. A₂ adenosine antagonists restored impaired insulin signaling in the skeletal muscle of HSu rats, but did not affect liver or adipose insulin signaling. Our results show that adenosine receptors exert opposite effects on insulin sensitivity, in control and insulin resistant states and strongly suggest that A₂ adenosine receptors in the skeletal muscle are the majors responsible for whole-body insulin sensitivity.

Effect of caffeine ingestion on free-throw performance in college basketball players

Background

It is currently unclear whether pre-exercise caffeine ingestion can improve free-throw shooting performance, a vital skill in basketball. The purpose of this study was to investigate the effects of caffeine on free-throw shooting performance in college-aged basketball players.

Methods

Twelve males (23.1 ± 1.9 years; 180.1 ± 8.8 cm; 77.1 ± 12.4 kg) and six females (22.0 ± 1.3 years; 169.4 ± 8.9 cm; 67.0 ± 11.1 kg) who competed at the college level ingested 6 mg per kg of body mass of (a) caffeine or (b) maltodextrin (placebo) on two separate occasions in a random order. After 60 min, they performed five sets of a match-simulated basketball protocol comprising six sideline-to-sideline sprints on a standard basketball court followed by two free-throws after each set. The number of successful shots was counted. Heart rate and rating of perceived exertion (RPE) after each sprint set were also recorded.

Results

Caffeine ingestion did not improve overall free-throw success (caffeine = 6.1 ± 1.7 vs. placebo = 5.5 ± 2.0; p = 0.34) compared with placebo across all five sets. There was no change in shooting accuracy across sprint sets in either trial despite significant increases in both heart rate and RPE. Caffeine increased heart rate (p = 0.02) but had no effect on RPE (p = 0.57) across five sets compared with placebo.

Conclusions

Ingestion of 6 mg of caffeine per kg of body mass did not improve basketball free-throw performance. Free-throw performance did not deteriorate with increasing number of sprint sets.

904 nm Low-Level Laser Irradiation Decreases Expression of Catabolism-Related Genes in White Adipose Tissue of Wistar Rats: Possible Roles of Laser on Metabolism

Background: Adipose tissue is the main energy storage tissue in the body. Its catabolic and anabolic responses depend on several factors, such as nutritional status, metabolic profile, and hormonal signaling. There are few studies addressing the effects of laser photobiomodulation (PBM) on adipose tissue and results are controversial. Objective: Our purpose was to investigate the metabolic effects of PBM on adipose tissue from Wistar rats supplemented or not with caffeine. Materials and methods: Wistar rats were divided into four groups: control (CTL), laser-treated [CTL (L)], caffeine (CAF), and caffeine+PBM [CAF (L)]. Blood was extracted for quantification of triglyceride and cholesterol levels and white adipose tissues were collected for analysis. We evaluated gene expression in the adipose tissue for the leptin receptor, lipase-sensitive hormone, tumor necrosis factor alpha, and beta adrenergic receptor. Results: We demonstrated that the low-level laser irradiation was able to increase the feed intake of the animals and the relative mass of the adipose tissue in the CTL (L) group compared with CTL. Laser treatment also increases serum triglycerides [CTL = 46.99 ± 5.87; CTL (L) = 57.46 ± 14.38; CAF = 43.98 ± 5.17; and CAF (L) = 56.9 ± 6.12; p = 0.007] and total cholesterol (CTL = 70.62 ± 6.80; CTL (L) = 79.41 ± 13.07; CAF = 71.01 ± 5.52; and CAF (L) = 79.23 ± 6.881; p = 0.003). Conclusions: Laser PBM decreased gene expression of the studied genes in the adipose tissue, indicating that PBM is able to block the catabolic responses of this tissue. Interestingly, the CAF (L) and CAF animals presented the same CLT (L) phenotype, however, without increasing the feed intake and the relative weight of the adipose tissue. The description of these phenomena opens a new perspective for the study of the action of low-level laser in adipose tissue.

Intermittent Nonhabitual Coffee Consumption and Risk of Atrial Fibrillation: The Multi-Ethnic Study of Atherosclerosis

Background

Though it is a widely held belief that caffeinated beverages predispose individuals to arrhythmias, it is not clear whether regular coffee consumption is associated with development of atrial fibrillation (AF).

Objective

We examined the association between long-term coffee consumption and development of AF in both habitual (≥0.5 cups of daily coffee) and nonhabitual (<0.5 cups/day) drinkers.

Methods

A total of 5,972 men and women, aged 45-84 years and without a history of cardiovascular disease at baseline in the Multi-Ethnic Study of Atherosclerosis (MESA) were followed from 2000 to 2014 for incident AF with baseline coffee consumption assessed in 2000-2002 via a Food Frequency Questionnaire and divided into quartiles of 0 cups/day, >0 to <0.5 cups/day, ≥0.5 to 1.5 cups/day, and ≥1.5 cups/day.

Results

Out of the 828 incident cases of AF, intermittent coffee consumption (>0 to 0.5 cups of daily coffee) was associated with a greater risk of incident AF (HR 1.22, 95% CI 1.01-1.48) relative to 0 cups/day in multivariable Cox proportional hazards models after adjustment for numerous AF risk factors. This relation was particularly pronounced in men (adjusted HR=1.36, 95% CI 1.04-1.77). Higher coffee consumption was not associated with AF risk (HR 1.03, 95%CI 0.93-1.14 for ≥0.5 to 1.5 cups/day and 1.05, 95%CI 0.97-1.13 for ≥1.5 cups/day).

Conclusions

While there appears to be no dose-response association between habitual coffee intake and AF risk, we found evidence that intermittent, but not habitual, coffee consumption is associated with a modestly increased risk of incident AF that deserves further study.

Cardiac autonomic activity during sleep deprivation with and without caffeine administration

Caffeine is often consumed to mitigate degraded alertness associated with sleep deprivation. Both caffeine and sleep deprivation have been implicated in cardiovascular disease, but evidence is largely anecdotal. We determined the effects of sleep deprivation and caffeine on markers of cardiac autonomic activity. Twelve healthy young adults completed an 18-day laboratory study. They were exposed to three 48 h sessions of acute total sleep deprivation (TSD), each separated by three recovery days. In randomized, counter-balanced order, subjects received 0 mg (placebo), 200 mg, or 300 mg of caffeine at 12 h intervals during each sleep deprivation session. Every 2 h during scheduled wakefulness, a 15-minute neurobehavioral task battery was administered, during which heart rate (HR) and the high frequency (HF) component of the HR variability power spectrum (HF-HRV) were measured. Caffeine administration decreased HR and increased HF-HRV, indicating elevated parasympathetic activity. The 300 mg caffeine dose did not significantly affect autonomic activity to a greater extent than the 200 mg dose. There was no significant effect of 48 h of TSD on HR, whereas there was a small increase across hours awake in HF-HRV. There was no significant interaction of TSD with caffeine. Circadian rhythmicity in HR and HF-HRV surpassed the magnitude of the effects of caffeine and TSD. Caffeine and acute TSD thus produced only modest changes in cardiac autonomic activity, unlikely to have immediate clinical implications in healthy young adults. However, further research is needed to determine the long-term effects of chronic exposure to sleep loss and/or caffeine on cardiac health, and to determine the generalizability of our findings to non-healthy populations.

Coffee and Endothelial Function: A Coffee Paradox?

Coffee is a popular beverage throughout the world. Coffee contains various chemical compounds (e.g., caffeine, chlorogenic acids, hydroxyhydroquinone, kahweol, cafestol, and complex chemical mixtures). Caffeine is also the most widely consumed pharmacological substance in the world and is included in various beverages (e.g., coffee, tea, soft drinks, and energy drinks), products containing chocolate, and drugs. The effects of coffee and caffeine on cardiovascular diseases remain controversial. It is well known that there are J-curve-type or U-curve-type associations of coffee consumption with cardiovascular events including myocardial infarction and stroke. However, there is little information on the direct and indirect effects of coffee consumption on endothelial function in humans. It is likely that the coffee paradox or caffeine paradox exists the association of coffee intake with cardiovascular diseases, cardiovascular outcomes, and endothelial function. This review focusses on the effects of coffee and caffeine on endothelial function from molecular mechanisms to clinical perspectives.

Effects of caffeine on intraocular pressure are subject to tolerance: a comparative study between low and high caffeine consumers

BACKGROUND

Caffeine has a well-established effect on intraocular pressure (IOP) and ocular perfusion pressure (OPP); however, the possible differences between low- and high-caffeine consumers remain unknown.

METHODS

In this placebo-controlled, double-blind, and balanced crossover study, 40 healthy individuals were divided in low- (n = 21) and high (n = 19)-caffeine consumers, according to their daily caffeine consumption. All participants ingested either caffeine (4 mg/kg) or placebo, and IOP and OPP were measured after 30, 60, and 90 min of ingesting caffeine or placebo. Subjective feelings of arousal were also obtained.

RESULTS

Caffeine induced an acute IOP rise (p < 0.001, ƞ_p² = 0.408), whereas habitual caffeine demonstrated a mediating effect on the IOP changes induced by caffeine intake, with high-caffeine consumers showing a less accentuated IOP rise in comparison to low-caffeine consumers. The greatest IOP change induced by caffeine intake was reached after 90 min from capsule ingestion, being more accentuated for the low-caffeine consumers (+ 3.4 mmHg) than for the high-caffeine consumers (+ 1.2 mmHg). Consequently, the participants reported higher levels of perceived arousal after ingesting caffeine in comparison to placebo (p = 0.002, ƞ_p² = 0.222); however, similar responses were given by high- and low-caffeine consumers (p = 0.256). Our data did not reveal any effect of caffeine consumption on OPP (p = 0.304).

CONCLUSIONS

These results suggest that IOP responsiveness to caffeine ingestion is subject to tolerance, which could have important implication in the management of glaucoma. This finding may be due to alterations in the adenosine receptor system caused by chronic caffeine consumption. Future studies are needed to assess if these findings are also applicable to patients with glaucoma.