Acute effects of coffee on endothelial function in healthy subjects

Therapeutic Options for Migraines in the Microsurgical Patient: A Scoping Review

BACKGROUND

There exists an increasing array of treatments proposed to prevent, alleviate, and abort symptoms of a migraine; however, for patients who undergo reconstructive microsurgery, caution must be taken to preserve vascular integrity. This study is the first-to-date scoping review of vascular and bleeding risk of current migraine therapies, with the purpose of identifying potential therapeutic agents for postoperative migraine management appropriate for microsurgical patients.

METHODS

Currently available migraine therapeutics were compiled from the UpToDate software system and the American Academy of Family Physicians. A PubMed literature review was performed for each therapeutic's effect on bleeding or vascular involvement. Data were compiled into tables of abortive, symptom-controlling and prophylactic, and nonpharmacologic treatments. Expert microsurgeons reviewed the data to provide recommendations for optimized patient care.

RESULTS

Triptans and other ergot derivatives demonstrated strong evidence of vasoconstriction and were greatly advised against for immediate postmicrosurgical use. Novel pharmaceutical therapies such as lasmiditan and calcitonin gene-related peptide antagonists have no literature indicating potential for vasoconstriction or hematoma and remain an investigational option for abortive medical treatment. For symptom control, acetaminophen appears the safest option, with clinical judgment and further research needed for use of nonsteroidal antiinflammatory drugs. Alternative treatment techniques may include migraine prophylaxis with botulinum toxin injection or nutraceutical treatment by means of magnesium supplementation or coenzyme Q10 administration, minimizing the need for additional medication in the postoperative setting.

CONCLUSIONS

Patients undergoing reconstructive microsurgery have a unique medical profile limiting the therapeutic options available to treat migraines. This review provides preliminary evidence to be considered as a guide for prescribing therapeutics for migraine in the postoperative setting.

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.

Acute Effects of Coffee Consumption on Blood Pressure and Endothelial Function in Individuals with Hypertension on Antihypertensive Drug Treatment: A Randomized Crossover Trial

INTRODUCTION

Coffee is a complex brew that contains several bioactive compounds and some of them can influence blood pressure (BP) and endothelial function (EF), such as caffeine and chlorogenic acids (CGAs).

AIM

This study aimed to evaluate the acute effects of coffee on BP and EF in individuals with hypertension on drug treatment who were habitual coffee consumers.

METHODS

This randomized crossover trial assigned 16 adults with hypertension to receive three test beverages one week apart: caffeinated coffee (CC; 135 mg caffeine, 61 mg CGAs), decaffeinated coffee (DC; 5 mg caffeine, 68 mg CGAs), and water. BP was continuously evaluated from 15 min before to 90 min after test beverages by digital photoplethysmography. Reactive hyperemia index (RHI) assessed by peripheral arterial tonometry evaluated EF before and at 90 min after test beverages. At the same time points, microvascular reactivity was assessed by laser speckle contrast imaging. Repeated-measures-ANOVA evaluated the effect of time, the effect of beverage, and the interaction between time and beverage (treatment effect).

RESULTS

Although the intake of CC produced a significant increase in BP and a significant decrease in RHI, these changes were also observed after the intake of DC and were not significantly different from the modifications observed after the consumption of DC and water. Microvascular reactivity did not present significant changes after the 3 beverages.

CONCLUSION

CC in comparison with DC and water neither promoted an acute increase in BP nor produced an improvement or deleterious effect on EF in individuals with hypertension on drug treatment who were coffee consumers.

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.

Plant Polyphenols and Their Potential Benefits on Cardiovascular Health: A Review

Fruits, vegetables, and other food items contain phytochemicals or secondary metabolites which may be considered non-essential nutrients but have medicinal importance. These dietary phytochemicals exhibit chemopreventive and therapeutic effects against numerous diseases. Polyphenols are secondary metabolites found in vegetables, fruits, and grains. These compounds exhibit several health benefits such as immune modulators, vasodilators, and antioxidants. This review focuses on recent studies on using dietary polyphenols to treat cardiovascular disorders, atherosclerosis, and vascular endothelium deficits. We focus on exploring the safety of highly effective polyphenols to ensure their maximum impact on cardiac abnormalities and discuss recent epidemiological evidence and intervention trials related to these properties. Kaempferol, quercetin, and resveratrol prevent oxidative stress by regulating proteins that induce oxidation in heart tissues. In addition, polyphenols modulate the tone of the endothelium of vessels by releasing nitric oxide (NO) and reducing low-density lipoprotein (LDL) oxidation to prevent atherosclerosis. In cardiomyocytes, polyphenols suppress the expression of inflammatory markers and inhibit the production of inflammation markers to exert an anti-inflammatory response. Consequently, heart diseases such as strokes, hypertension, heart failure, and ischemic heart disease could be prevented by dietary polyphenols.

A moderate dosage of coffee causes acute retinal capillary perfusion decrease in healthy young individuals

AIM

Caffeinated beverages are very popular across populations and cultures, but quantitative evidence of the acute effects of moderate coffee doses on retinal perfusion is sparse and contradicting. Thus, the aim of this randomized, cross-over and parallel-group design study was to investigate whether moderate consumption of coffee alters macular retinal capillary perfusion in young healthy individuals.

METHODS

Twenty-seven young healthy individuals were recruited for this study. Acute changes in retinal microvasculature were assessed using spectral-domain optical coherence tomography angiography (SD-OCTA) at baseline, 0.5 h, and 2 h after intake of coffee, or water. Meanwhile, cerebral blood flow (CBF) and retina-choroid blood flow were evaluated in a parallel-group design (4 participants each in coffee or water group) using magnetic resonance imaging (MRI) with pseudo-continuous arterial spin labeling sequences.

RESULTS

Two hours after coffee intake, blood caffeine concentration increased from 0 to 5.05 ± 1.36 µg/mL. Coffee caused a significant decrease in retinal vessel diameter index (VDI) (19.05 ± 0.24 versus [vs] 19.13 ± 0.26; p < 0.001) and CBF in the frontal lobe (77.47 ± 15.21 mL/100 mL/min vs. 84.13 ± 15.55 mL/100 mL/min; p < 0.05) 2 h after intake. However, it significantly increased retina-choroid blood flow after 0.5 and 2 h (163.18 ± 61.07 mL/100 mL/min vs. 132.68 ± 70.47 mL/100 mL/min, p < 0.001, and 161.21 ± 47.95 vs. 132.68 ± 70.47; p < 0.001, respectively).

CONCLUSION

This is the first study to demonstrate the acute effects of daily dose coffee consumption on retinal capillary perfusion using SD-OCTA combinate with blood flow MRI. The findings imply that although moderate coffee intake caused a significant increase in retina-choroid blood flow, there was a significant acute decrease both in macular retinal capillary perfusion and CBF.

Relationship of Daily Coffee Intake with Vascular Function in Patients with Hypertension

We evaluated the relationship of daily coffee intake with endothelial function assessed by flow-mediated vasodilation and vascular smooth muscle function assessed by nitroglycerine-induced vasodilation in patients with hypertension. A total of 462 patients with hypertension were enrolled in this cross-sectional study. First, we divided the subjects into two groups based on information on daily coffee intake: no coffee group and coffee group. The median coffee intake was two cups per day in the coffee group. There were significant differences in both flow-mediated vasodilation (2.6 ± 2.8% in the no coffee group vs. 3.3 ± 2.9% in the coffee group, p = 0.04) and nitroglycerine-induced vasodilation (9.6 ± 5.5% in the no coffee group vs. 11.3 ± 5.4% in the coffee group, p = 0.02) between the two groups. After adjustment for confounding factors, the odds ratio for endothelial dysfunction (OR: 0.55, 95% CI: 0.32–0.95) and the odds ratio for vascular smooth muscle dysfunction (OR: 0.50, 95% CI: 0.28–0.89) were significantly lower in the coffee group than in the no coffee group. Next, we assessed the relationship of the amount of daily coffee intake with vascular function. Cubic spline curves revealed that patients with hypertension who drank half a cup to 2.5 cups of coffee per day had lower odds ratios for endothelial dysfunction assessed by flow-mediated vasodilation and vascular smooth muscle dysfunction assessed by nitroglycerine-induced vasodilation. Appropriate daily coffee intake might have beneficial effects on endothelial function and vascular smooth muscle function in patients with hypertension.

The Acute Effects of Prolonged Uninterrupted Sitting on Vascular Function: A Systematic Review and Meta-analysis

OBJECTIVE

This study aimed to determine the dose-response relationship between prolonged sitting and vascular function in healthy individuals and those with metabolic disturbances and to investigate the acute effects, on vascular function, of interventions that target interrupting prolonged sitting.

DESIGN

This is a systematic review with meta-analysis.

DATA SOURCES

Ovid Embase, Ovid Medline, PubMed, and CINAHL were searched from inception to 4 December 2020.

ELIGIBILITY CRITERIA

Randomized crossover trials, quasi-randomized trials, and parallel group trials where vascular function (flow-mediated dilation [FMD]) was assessed before and after an acute period of sedentary behavior was used in this study.

RESULTS

Prolonged sitting resulted in a significant decrease in the standardized mean change (SMC) for lower-limb FMD at the 120-min (SMC = -0.85, 95% confidence interval [CI] = -1.32 to -0.38) and 180-min (SMC = -1.18, 95% CI = -1.69 to -0.66) time points. A similar pattern was observed for lower-limb shear rate. No significant changes were observed for any outcomes in the upper limb. Subgroup analysis indicated that prolonged sitting decreased lower-limb FMD in healthy adults (SMC = -1.33, 95% CI = -1.89 to -0.78) who had higher a priori vascular endothelial function, but not in those with metabolic and vascular dysfunction (SMC = -0.51, 95% CI = -1.18 to 0.15). Interrupting sitting with active interruptions increased the standardized mean difference for FMD, relative to prolonged sitting, but it was not statistically significant (0.13, 95% CI = -0.20 to 0.45).

CONCLUSIONS

Lower-limb vascular function is progressively impaired as a consequence of prolonged sitting, up to 180 min. A similar trend was not observed in upper-limb vascular function. Subgroup analysis indicated that prolonged sitting negatively affects healthy populations, a finding not observed in those with metabolic disturbances. Regularly interrupting sitting with activity may be beneficial for those with metabolic disturbances.

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.

Sleep duration regularity, but not sleep duration, is associated with microvascular function in college students

STUDY OBJECTIVES

Vascular dysfunction is a hypothesized mechanism linking poor sleep habits to an increased incidence of cardiovascular diseases (CVDs). However, the vascular profile associated with free-living sleep duration and sleep regularity has not been well elucidated, particularly in young adults. Thus, this study aimed to evaluate the associations between mean sleep duration, regularity in sleep duration, and peripheral vascular function in young adult college students.

METHODS

Fifty-one healthy undergraduate students (20 ± 1 years) completed 14 days of 24-hour wrist actigraphy and subsequent vascular assessments. Macrovascular function was measured using brachial artery flow-mediated dilation (FMD) while microvascular function was measured via passive leg movement (PLM).

RESULTS

Mean sleep duration was unrelated to FMD and PLM. Conversely, more irregular sleep duration (14-day sleep duration standard deviation [SD]) was unfavorably associated with all three measures of PLM-induced hyperemia (peak leg blood flow [LBF], p = 0.01; change in LBF from baseline to peak, p < 0.01; LBF area under the curve, p < 0.01), and remained significant in regression models which adjusted for sex, body mass index, blood pressure, physical activity, alcohol and caffeine consumption, and sleep duration (all p < 0.05). When using a median split to dichotomize "low" and "high" sleep duration SD groups, those demonstrating high variability in sleep duration exhibited ~45% lower PLM responses compared with those demonstrating low variability.

CONCLUSIONS

Irregular sleep duration is associated with poorer microvascular function as early as young adulthood. These findings support the growing body of evidence that irregular sleep patterns may be an independent and modifiable risk factor for CVD.

Impact of green tea on the deleterious cardiometabolic effects of 7-days unhealthy lifestyle in young healthy males

PURPOSE

The aim of this study was to examine if catechin-rich green tea abrogates the negative effects of 7-days of physical inactivity and excessive calorie-intake on insulin homeostasis and peripheral vascular function.

METHODS

Using a randomized, double-blind, crossover design, twelve healthy men (29 ± 6 yrs) underwent 7-days unhealthy lifestyle (UL), including physical inactivity (-50% steps/day) and overfeeding (+50% kcal/day). This was combined with green tea consumption (UL-tea; 3 doses/day) or placebo (UL-placebo). Before and after each intervention, we examined postprandial blood glucose and insulin (3-h after a 1,202 kcal meal) and upper and lower limb vascular function (flow-mediated dilation (FMD%)) and carotid artery reactivity (CAR%).

RESULTS

UL-placebo increased postprandial glucose and insulin, while UL-tea decreased postprandial glucose and insulin (Time*Intervention interaction effects: both p < 0.05). UL-placebo decreased CAR% and femoral FMD%, while UL-tea prevented these effects (Time*Intervention interaction effects of p < 0.04 and p < 0.001, respectively). There was no main effect of Time or Time*Intervention interaction (both p > 0.05) for brachial FMD%.

CONCLUSION

Seven days of physical inactivity and overfeeding impair insulin homeostasis and vascular function. These effects were mitigated by a daily intake of catechin-rich green tea.

Effects of coffee consumption on arterial stiffness and endothelial function: a systematic review and meta-analysis of randomized clinical trials

BACKGROUND

Endothelial function (EF) and arterial stiffness (AS) are predictors of cardiovascular disease. As previous research concerning the effect of coffee intake on EF and AS was controversial, we conducted a systematic review and meta-analysis to synthesize research.

METHODS

We performed a systematic search in PubMed, Scopus and Web of Science to find clinical trials investigating the effect of coffee intake on EF or AS up to March 2020.Random-effects models were used to estimate the pooled weighted mean difference (WMD) between intervention and control groups for randomized controlled trials (RCTs). Between study heterogeneity was estimated using Cochran's Q and the I ²-inconsistency index. Internal validity of included randomized trials was determined with the Cochrane Collaboration's tool for assessing the risk of bias.

RESULTS

Twenty-three articles were included for qualitative and 11 articles for quantitative synthesis. Meta-analysis of 14 RCTs (nine articles) indicated a positive short-term (postprandial) effect of coffee intake on flow-mediated dilation (FMD) as a measure of EF (WMD: 1.93%[95% CI: 1.10-2.75]; I ²= 97.9%). Meta-analysis of three long-term RCTs(two articles) found no such effect on FMD (WMD: -0.08% [-3.82 to 3.66]; I ²= 61.4%).Most short-term information was from studies at low or unclear risk of bias, while the proportion of long-term information from studies at high risk of bias was considerable.

CONCLUSION

The results from this meta-analysis suggest a beneficial short-term effect of coffee intake on EF as measured by FMD. However, there might be unfavorable effects on AS. Our findings must be interpreted cautiously as the number of studies were low and included studies had a considerable risk of bias.

Assessment of the sublingual microcirculation with the GlycoCheck system: Reproducibility and examination conditions

Background

The glycocalyx is an extracellular layer lining the lumen of the vascular endothelium, protecting the endothelium from shear stress and atherosclerosis and contributes to coagulation, immune response and microvascular perfusion. The GlycoCheck system estimates glycocalyx’ thickness in vessels under the tongue from perfused boundary region (PBR) and microvascular perfusion (red blood cell (RBC) filling) via a camera and dedicated software.

Objectives

Evaluating reproducibility and influence of examination conditions on measurements with the GlycoCheck system.

Methods

Open, randomised, controlled study including 42 healthy smokers investigating day-to-day, side-of-tongue, inter-investigator variance, intraclass-correlation (ICC) and influence of examination conditions at intervals from 0–180 minutes on PBR and RBC filling.

Results

Mean (SD) age was 24.9 (6.1) years, 52% were male. There was no significant intra- or inter-investigator variation for PBR or RBC filling nor for PBR for side-of-tongue. A small day-to-day variance was found for PBR (0.012μm, p = 0.007) and RBC filling (0.003%, p = 0.005) and side-of-tongue, RBC filling (0.025%, p = 0.009). ICC was modest but highly improved by increasing measurements. Small significant influence of cigarette smoking (from 40–180 minutes), high calorie meal intake and coffee consumption was found. The latter two peaking immediately and tapering off but remained significant up to 180 minutes, highest PBR changes for the three being 0.042μm (p<0.05), 0.183μm (p<0.001) and 0.160μm (p<0.05) respectively.

Conclusions

Measurements with the GlycoCheck system have a moderate reproducibility, but highly increases with multiple measurements and a small day-to-day variability. Smoking, meal and coffee intake had effects up to 180 minutes, abstinence is recommended at least 180 minutes before GlycoCheck measurements. Future studies should standardise conditions during measurements.

Role of Polyphenols and Carotenoids in Endothelial Dysfunction: An Overview from Classic to Innovative Biomarkers

Nowadays, the dramatically increased prevalence of metabolic diseases, such as obesity and diabetes mellitus and their related complications, including endothelial dysfunction and cardiovascular disease, represents one of the leading causes of death worldwide. Dietary nutrients together with healthy lifestyles have a crucial role in the endothelium health-promoting effects. From a growing body of evidence, active natural compounds from food, including polyphenols and carotenoids, have attracted particular attention as a complementary therapy on atherosclerosis and cardiovascular disease, as well as preventive approaches through the attenuation of inflammation and oxidative stress. They mainly act as radical scavengers by promoting a variety of biological mechanisms, such as improvements in endothelial function, blood pressure, platelet activity, and insulin sensitivity, and by modulating various known biomarkers. The present review highlights the role of polyphenols and carotenoids in early endothelial dysfunction with attention to their beneficial effect in modulating both classical and recent technologically generated emerging biomarkers. These, alone or in combination, can play an important role in the prediction, diagnosis, and evolution of cardiovascular disease. However, a main challenge is to speed up early and prompt new interventions in order to prevent or slow down disease progression, even with an adequate intake of bioactive compounds. Hence, there is an urgent need of new more validated, appropriate, and reliable diagnostic and therapeutic biomarkers useful to diagnose endothelial dysfunction at an earlier stage.

The effects of green coffee extract supplementation on glycemic indices and lipid profile in adults: a systematic review and dose-response meta-analysis of clinical trials

Background

The role of coffee consumption in the risk of cardiovascular diseases has been debated for many years. The current study aimed to summarize earlier evidence on the effects of green coffee extract (GCE) supplementation on glycemic indices and lipid profile.

Methods

We searched available online databases for relevant clinical trials published up to October 2019. All clinical trials investigating the effect of GCE supplementation, compared with a control group, on fasting blood glucose (FBG), serum insulin, total cholesterol (TC), triglyceride (TG), low-density lipoprotein (LDL), and high-density lipoprotein (HDL) were included. Overall, 14 clinical trials with a total sample size of 766 participants were included in the current meta-analysis.

Results

We found a significant reducing effect of GCE supplementation on FBG (weighted mean difference (WMD): -2.35, 95% CI: − 3.78, − 0.92 mg/dL, P = 0.001) and serum insulin (WMD: -0.63, 95% CI: − 1.11, − 0.15 μU/L, P = 0.01). With regard to lipid profile, we observed a significant reduction only in serum levels of TC following GCE supplementation in the overall meta-analysis (WMD: -4.51, 95% CI: − 8.39, − 0.64, P = 0.02). However, subgroup analysis showed a significant reduction in serum TG in studies enrolled both genders. Also, such a significant reduction was seen in serum levels of LDL and HDL when the analyses confined to studies with intervention duration of ≥8 weeks and those included female subjects. In the non-linear dose-response analyses, we found that the effects of chlorogenic acid (CGA) dosage, the main polyphenol in GCE, on FBG, TG and HDL were in the non-linear fashions.

Conclusion

In conclusion, we found that GCE supplementation improved FBG and serum levels of insulin and TC. Also, there was a significant improvement in other markers of lipid profile in some subgroups of clinical trials.

Caffeine Augments the Prothrombotic but Not the Fibrinolytic Response to Exercise

Caffeine, a popular ergogenic supplement, induces neural and vascular changes that may influence coagulation and/or fibrinolysis at rest and during exercise.

PURPOSE

The purpose of this study was to assess the effect of a single dose of caffeine on measures of coagulation and fibrinolysis before and after a single bout of high-intensity exercise.

METHODS

Forty-eight men (age, 23 ± 3 yr; body mass index, 24 ± 3 kg·m) completed two trials, with 6 mg·kg of caffeine (CAFF) or placebo (PLAC), in random order, followed by a maximal cycle ergometer test. Plasma concentrations of fibrinogen, factor VIII antigen, active tissue plasminogen activator (tPA:c), tissue plasminogen activator antigen (tPA:g), and active plasminogen activator inhibitor-1 (PAI-1:c) were assessed at baseline and immediately after exercise.

RESULTS

Exercise led to significant changes in tPA:c (Δ 8.5 ± 4.36 IU·mL for CAFF, 6.6 ± 3.7 for PLAC), tPA:g (Δ 2.4 ± 3.2 ng·mL for CAFF, 1.9 ± 3.1 for PLAC), fibrinogen (Δ 30.6 ± 61.4 mg·dL for CAFF, 28.1 ± 66.4 for PLAC), and PAI-1:c (Δ -3.4 ± 7.9 IU·mL for CAFF, -4.0 ± 12.0 for PLAC) (all P < 0.05), but no effect of condition or time-condition interactions were observed. Main effects of time, condition, and a significant time-condition interaction were observed for factor VIII, which increased from 1.0 ± 0.4 IU·mL to 3.3 ± 1.3 IU·mL with CAFF and 1.0 ± 0.4 IU·mL to 2.4 ± 0.9 IU·mL with PLAC.

CONCLUSIONS

Coagulation potential during exercise is augmented after caffeine intake, without a similar increase in fibrinolysis. These results suggest caffeine intake may increase risk of a thrombotic event during exercise.

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 coffee consumption on glucose metabolism: A systematic review of clinical trials

Epidemiological studies indicate an inverse association of coffee consumption with risk of type 2 diabetes mellitus. However, studies to determine the clinical effects of coffee consumption on the glucose metabolism biomarkers remain uncertain. The aim of this systematic review was to evaluate the effects of coffee consumption on glucose metabolism. A search of electronic databases (PubMed and Web of Science) was performed identifying studies published until September 2017. Eight clinical trials (n = 247 subjects) were identified for analyses. Participants and studies characteristics, main findings, and study quality (Jadad Score) were reported. Short-term (1-3 h) and long-term (2-16 weeks) studies were summarized separately. Short-term studies showed that consumption of caffeinated coffee may increase the area under the curve for glucose response, while for long-term studies, caffeinated coffee may improve the glycaemic metabolism by reducing the glucose curve and increasing the insulin response. The findings suggest that consumption of caffeinated coffee may lead to unfavourable acute effects; however, an improvement on glucose metabolism was found on long-term follow-up.

Coffee consumption and plasma biomarkers of metabolic and inflammatory pathways in US health professionals

BACKGROUND

Coffee consumption has been linked to lower risk of various health outcomes. However, the biological pathways mediating the associations remain poorly understood.

OBJECTIVES

The aim of this study was to assess the association between coffee consumption and concentrations of plasma biomarkers in key metabolic and inflammatory pathways underlying common chronic diseases.

METHODS

We investigated the associations of total, caffeinated, and decaffeinated coffee consumption with 14 plasma biomarkers, including C-peptide, insulin-like growth factor 1 (IGF-1), IGF binding protein (IGFBP) 1, IGFBP-3, estrone, total and free estradiol, total and free testosterone, sex hormone-binding globulin (SHBG), total adiponectin, high-molecular-weight (HMW) adiponectin, leptin, C-reactive protein (CRP), interleukin 6 (IL-6), and soluble tumor necrosis factor receptor 2 (sTNFR-2). Data were derived from 2 cohorts of 15,551 women (Nurses' Health Study) and 7397 men (Health Professionals Follow-Up Study), who provided detailed dietary data before blood draw and were free of diabetes, cardiovascular disease, or cancer at the time of blood draw. Multivariable linear regression was used to calculate the percentage difference of biomarker concentrations comparing coffee drinkers with nondrinkers, after adjusting for a variety of demographic, clinical, and lifestyle factors.

RESULTS

Compared with nondrinkers, participants who drank ≥4 cups of total coffee/d had lower concentrations of C-peptide (-8.7%), IGFBP-3 (-2.2%), estrone (-6.4%), total estradiol (-5.7%), free estradiol (-8.1%), leptin (-6.4%), CRP (-16.6%), IL-6 (-8.1%), and sTNFR-2 (-5.8%) and higher concentrations of SHBG (5.0%), total testosterone (7.3% in women and 5.3% in men), total adiponectin (9.3%), and HMW adiponectin (17.2%). The results were largely similar for caffeinated and decaffeinated coffee.

CONCLUSION

Our data indicate that coffee consumption is associated with favorable profiles of numerous biomarkers in key metabolic and inflammatory pathways. This trial was registered at clinicaltrials.gov as NCT03419455.

TNF-α-induced oxidative stress and endothelial dysfunction in EA.hy926 cells is prevented by mate and green coffee extracts, 5-caffeoylquinic acid and its microbial metabolite, dihydrocaffeic acid

The main phenol in mate and coffee, 5-caffeoylquinic-acid (5-CQA), and its relevant microbial metabolites, dihydrocaffeic (DHCA) and dihydroferulic (DHFA) acids, have shown oxidative-stress protective effects in HepG2 cells. To evaluate possible endothelial-protective effects of the extracts and compounds, endothelial EA.hy926 cells were pre-treated with yerba mate (YME) and green coffee bean (GCBE) phenolic extracts, 5-CQA, DHCA and DHFA and afterwards stressed with tumour-necrosis-factor-alpha (TNF-α). Then oxidative-stress markers and endothelial-nitric-oxide-synthase levels were studied. TNF-α (10 ng/mL, 24 h) depleted reduced glutathione (GSH) and eNOS levels, increased reactive oxygen species (ROS) production, glutathione peroxidase (GPx) and reductase (GR) activities, and protein oxidation (carbonyl groups, CG) in EA.hy926 cells. Pre-treatment with YME, GCBE, 5-CQA, DHCA at certain physiological concentrations, lowered ROS production, recovered depleted GSH, reduced GR and GPx activities, and CG levels, and enhanced eNOS concentration.. YME, GCBE and 5-CQA show antioxidant effects in endothelial cells playing DHCA an important role in such protection; moreover, the extracts, 5-CQA, DHCA and DHFA increased eNOS levels.

Decaffeinated coffee improves insulin sensitivity in healthy men

Epidemiological studies have found coffee consumption is associated with a lower risk for type 2 diabetes mellitus, but the underlying mechanisms remain unclear. Thus, the aim of this randomised, cross-over single-blind study was to investigate the effects of regular coffee, regular coffee with sugar and decaffeinated coffee consumption on glucose metabolism and incretin hormones. Seventeen healthy men participated in five trials each, during which they consumed coffee (decaffeinated, regular (containing caffeine) or regular with sugar) or water (with or without sugar). After 1 h of each intervention, they received an oral glucose tolerance test with one intravenous dose of [1-13C]glucose. The Oral Dose Intravenous Label Experiment was applied and glucose and insulin levels were interpreted using a stable isotope two-compartment minimal model. A mixed-model procedure (PROC MIXED), with subject as random effect and time as repeated measure, was used to compare the effects of the beverages on glucose metabolism and incretin parameters (glucose-dependent insulinotropic peptide (GIP)) and glucagon-like peptide-1 (GLP-1)). Insulin sensitivity was higher with decaffeinated coffee than with water (P<0·05). Regular coffee with sugar did not significantly affect glucose, insulin, C-peptide and incretin hormones, compared with water with sugar. Glucose, insulin, C-peptide, GLP-1 and GIP levels were not statistically different after regular and decaffeinated coffee compared with water. Our findings demonstrated that the consumption of decaffeinated coffee improves insulin sensitivity without changing incretin hormones levels. There was no short-term adverse effect on glucose homoeostasis, after an oral glucose challenge, attributable to the consumption of regular coffee with sugar.

Coffee with a high content of chlorogenic acids and low content of hydroxyhydroquinone improves postprandial endothelial dysfunction in patients with borderline and stage 1 hypertension

Purpose

The purpose of this study was to evaluate acute effects of coffee with a high content of chlorogenic acids and different hydroxyhydroquinone contents on postprandial endothelial dysfunction.

Methods

This was a single-blind, randomized, placebo-controlled, crossover-within-subject clinical trial. A total of 37 patients with borderline or stage 1 hypertension were randomized to two study groups. The participants consumed a test meal with a single intake of the test coffee. Subjects in the Study 1 group were randomized to single intake of coffee with a high content of chlorogenic acids and low content of hydroxyhydroquinone or coffee with a high content of chlorogenic acids and a high content of hydroxyhydroquinone with crossover. Subjects in the Study 2 group were randomized to single intake of coffee with a high content of chlorogenic acids and low content of hydroxyhydroquinone or placebo coffee with crossover. Endothelial function assessed by flow-mediated vasodilation and plasma concentration of 8-isoprostanes were measured at baseline and at 1 and 2 h after coffee intake.

Results

Compared with baseline values, single intake of coffee with a high content of chlorogenic acids and low content of hydroxyhydroquinone, but not coffee with a high content of chlorogenic acids and high content of hydroxyhydroquinone or placebo coffee, significantly improved postprandial flow-mediated vasodilation and decreased circulating 8-isoprostane levels.

Conclusions

These findings suggest that a single intake of coffee with a high content of chlorogenic acids and low content of hydroxyhydroquinone is effective for improving postprandial endothelial dysfunction.

Clinical Trial Registration

URL for Clinical Trial: https://upload.umin.ac.jp; Registration Number for Clinical Trial: UMIN000013283.

The acute effect of black tea consumption on resistance artery endothelial function in healthy subjects. A randomized controlled trial

BACKGROUND & AIMS

Black tea is a main source of flavonoids in the Western diet and has been associated with reduced risk for cardiovascular disease, possibly through lowering blood pressure. These effects may be mediated through improving endothelial function of resistance arteries. The aim of this study was therefore to examine the acute impact of black tea on forearm resistance artery endothelial function in healthy, normotensive middle-aged subjects.

METHODS

Twenty middle-aged men and women (age-range 45-75 years) were recruited into a double-blind, randomized, placebo-controlled crossover intervention study. Forearm resistance artery blood flow (FBF, measured using venous occlusion plethysmography) in response to incremental doses of acetylcholine, sodium nitroprusside and L-N^G-monomethyl arginine were determined 2 h after consumption of either black tea containing ∼400 mg flavonoids (equivalent to 2-3 cups of tea) or a taste- and color-matched placebo.

RESULTS

The mean FBF-response to acetylcholine after tea consumption was 23% higher compared to the response after placebo (95% CI: -20%, +88%), but this difference did not reach statistical significance (P = 0.32). No significant differences in the FBF-responses to sodium nitroprusside and L-N^G-monomethyl arginine were found between the tea and placebo interventions (P = 0.96 and 0.74, respectively). Correcting FBF for changes in blood pressure did not alter the outcomes.

CONCLUSIONS

We found no evidence that acute intake of black tea significantly altered endothelium-dependent vasodilation of forearm resistance arteries in healthy middle-aged subjects. Interventions with a longer duration of tea ingestion are required to further explore the (long-term) impact of tea flavonoids on blood pressure regulatory mechanisms. This trial was registered at clinicaltrials.gov as NCT02328339.

CORP: Ultrasound assessment of vascular function with the passive leg movement technique

As dysfunction of the vascular system is an early, modifiable step in the progression of many cardiovascular diseases, there is demand for methods to monitor the health of the vascular system noninvasively in clinical and research settings. Validated by very good agreement with more technical assessments of vascular function, like intra-arterial drug infusions and flow-mediated dilation, the passive leg movement (PLM) technique has emerged as a powerful, yet relatively simple, test of peripheral vascular function. In the PLM technique, the change in leg blood flow elicited by the passive movement of the leg through a 90° range of motion is quantified with Doppler ultrasound. This relatively easy-to-learn test has proven to be ≤80% dependent on nitric oxide bioavailability and is especially adept at determining peripheral vascular function across the spectrum of cardiovascular health. Indeed, multiple reports have documented that individuals with decreased cardiovascular health such as the elderly and those with heart failure tend to exhibit a substantially blunted PLM-induced hyperemic response (~50 and ~85% reduction, respectively) compared with populations with good cardiovascular health such as young individuals. As specific guidelines have not yet been put forth, the purpose of this Cores of Reproducibility in Physiology (CORP) article is to provide a comprehensive reference for the assessment and interpretation of vascular function with PLM with the aim to increase reproducibility and consistency among studies and facilitate the use of PLM as a research tool with clinical relevance.

The role of polyphenols in modern nutrition

Polyphenols are found in plant‐based foods and beverages, notably apples, berries, citrus fruit, plums, broccoli, cocoa, tea and coffee and many others. There is substantial epidemiological evidence that a diet high in polyphenol‐rich fruit, vegetables, cocoa and beverages protects against developing cardiovascular disease and type 2 diabetes. The absorption and metabolism of these compounds have been well described and, for many, the gut microbiota play a critical role in absorption; taking into consideration the parent compound and the metabolites from colon bacteria catabolism, more than 80% of a dose can be absorbed and ultimately excreted in the urine. Common polyphenols in the diet are flavanols (cocoa, tea, apples, broad beans), flavanones (hesperidin in citrus fruit), hydroxycinnamates (coffee, many fruits), flavonols (quercetin in onions, apples and tea) and anthocyanins (berries). Many intervention studies, mechanistic in vitro data and epidemiological studies support a role for polyphenols against the development of chronic diseases. For example, flavanols decrease endothelial dysfunction, lower blood pressure and cholesterol, and modulate energy metabolism. Coffee and tea both reduce the risk of developing type 2 diabetes, through action of their constituent polyphenols. Despite extensive research, the exact mechanisms of action of polyphenols in the human body have not been decisively proven, but there is strong evidence that some targets such as nitric oxide metabolism, carbohydrate digestion and oxidative enzymes are important for health benefits. Consumption of polyphenols as healthy dietary components is consistent with the advice to eat five or more portions of fruit and vegetables per day, but it is currently difficult to recommend what ‘doses’ of specific polyphenols should be consumed to derive maximum benefit.

Acute effects of coffee on skin blood flow and microvascular function

OBJECTIVE

Studies on the acute effects of coffee on the microcirculation have shown contradicting results. This study aimed to investigate if intake of caffeine-containing coffee changes blood flow and microvascular reactivity in the skin.

METHODS

We measured acute changes in cutaneous vascular conductance (CVC) in the forearm and the tip of the finger, the microvascular response to transdermal iontophoresis of acetylcholine (ACh) and sodium nitroprusside (SNP) and post-occlusive reactive hyperemia (PORH) in the skin, after intake of caffeinated or decaffeinated coffee.

RESULTS

Vasodilatation during iontophoresis of ACh was significantly stronger after intake of caffeinated coffee compared to after intake of decaffeinated coffee (1.26±0.20PU/mmHg vs. 1.13±0.38PU/mmHg, P<0.001). Forearm CVC before and after PORH were not affected by caffeinated and decaffeinated coffee. After intake of caffeinated coffee, a more pronounced decrease in CVC in the fingertip was observed compared to after intake of decaffeinated coffee (-1.36PU/mmHg vs. -0.52PU/mmHg, P=0.002).

CONCLUSIONS

Caffeine, as ingested by drinking caffeinated coffee acutely improves endothelium-dependent microvascular responses in the forearm skin, while endothelium-independent responses to PORH and SNP iontophoresis are not affected. Blood flow in the fingertip decreases markedly during the first hour after drinking caffeinated coffee compared to decaffeinated coffee.

Tea-induced improvement of endothelial function in humans: No role for epigallocatechin gallate (EGCG)

Consumption of tea is inversely associated with cardiovascular diseases. However, the active compound(s) responsible for the protective effects of tea are unknown. Although many favorable cardiovascular effects in vitro are mediated by epigallocatechin gallate (EGCG), its contribution to the beneficial effects of tea in vivo remains unresolved. In a randomised crossover study, a single dose of 200 mg EGCG was applied in three different formulas (as green tea beverage, green tea extract (GTE), and isolated EGCG) to 50 healthy men. Flow-mediated dilation (FMD) and endothelial-independent nitro-mediated dilation (NMD) was measured before and two hours after ingestion. Plasma levels of tea compounds were determined after each intervention and correlated with FMD. FMD significantly improved after consumption of green tea containing 200 mg EGCG (p < 0.01). However, GTE and EGCG had no significant effect on FMD. NMD did not significantly differ between interventions. EGCG plasma levels were highest after administration of EGCG and lowest after consumption of green tea. Plasma levels of caffeine increased after green tea consumption. The results show that EGCG is most likely not involved in improvement of flow-mediated dilation by green tea. Instead, other tea compounds, metabolites or combinations thereof may play a role.

Electronic cigarettes—A review of the physiological health effects

Electronic cigarettes (ECs) are devices that are used recreationally or as smoking cessation tools, and have become increasingly popular in recent years. We conducted a review of the available literature to determine the health effects caused by the use of these devices. A heating element in the EC aerosolizes a solution of propylene glycol, glycerol, nicotine (optional), and flavouring (optional). These compounds are generally harmless on their own. However, upon heating, they produce various carcinogens and irritants. We found that concentrations of these toxicants vary significantly depending on the type of EC device, the type of EC liquid, and the smoking behaviour of the user. Exposure to these vapours can cause inflammation and oxidative damage to in vitro and in vivo cells. EC aerosol can also potentially affect organ systems and especially cardiovascular and lung function. We concluded that EC use causes acute effects on health but not as severe as those of conventional cigarettes (CCs). These devices could, therefore, be of use for smokers of CCs wishing to quit. However, as EC aerosol introduces new toxicants not found in CCs, long-term studies are needed to investigate possible chronic effects associated with EC use.

Sources of inaccuracy in the measurement of adult patients' resting blood pressure in clinical settings: a systematic review

BACKGROUND

To interpret blood pressure (BP) data appropriately, healthcare providers need to be knowledgeable of the factors that can potentially impact the accuracy of BP measurement and contribute to variability between measurements.

METHODS

A systematic review of studies quantifying BP measurement inaccuracy. Medline and CINAHL databases were searched for empirical articles and systematic reviews published up to June 2015. Empirical articles were included if they reported a study that was relevant to the measurement of adult patients' resting BP at the upper arm in a clinical setting (e.g. ward or office); identified a specific source of inaccuracy; and quantified its effect. Reference lists and reviews were searched for additional articles.

RESULTS

A total of 328 empirical studies were included. They investigated 29 potential sources of inaccuracy, categorized as relating to the patient, device, procedure or observer. Significant directional effects were found for 27; however, for some, the effects were inconsistent in direction. Compared with true resting BP, significant effects of individual sources ranged from -23.6 to +33 mmHg SBP and -14 to +23 mmHg DBP.

CONCLUSION

A single BP value outside the expected range should be interpreted with caution and not taken as a definitive indicator of clinical deterioration. Where a measurement is abnormally high or low, further measurements should be taken and averaged. Wherever possible, BP values should be recorded graphically within ranges. This may reduce the impact of sources of inaccuracy and reduce the scope for misinterpretations based on small, likely erroneous or misleading, changes.

Coffee consumption and risk of cardiovascular events in hypertensive patients. Results from the HARVEST

BACKGROUND

Controversy still exists about the long-term cardiovascular effects of coffee consumption in hypertension.

METHODS

The predictive capacity of coffee use for cardiovascular events (CVEs) was investigated in 1204 participants from the HARVEST, a prospective cohort study of non-diabetic subjects aged 18-45years, screened for stage 1 hypertension. Subjects were grouped into three categories of coffee drinking, non-drinkers (none), moderate drinkers (1 to 3cups/day) and heavy drinkers (4or more cups/day). Multivariate Cox proportional hazards models were developed adjusting for possible confounding variables and risk factors.

RESULTS

During a median follow-up of 12.6years, CVEs were developed by 60 participants. CVEs were more common among coffee drinkers than abstainers (abstainers, 2.2%; moderate drinkers, 7.0%; heavy drinkers, 14.0%; p for trend=0.0003). In a multivariable Cox regression model, coffee use was a significant predictor of CVE in both coffee categories, with a hazard ratio of 2.8 (95% CI, 1.0-7.9) in moderate coffee drinkers and of 4.5 (1.4-14.2) in heavy drinkers compared to abstainers. After inclusion of change in body weight (p=ns), incident hypertension (p=0.027) and presence of diabetes/prediabetes (p=ns) at follow-up end, the association with CVE was attenuated but remained significant in heavy coffee drinkers (HR, 95% CI, 3.4, 1.04-11.3).

CONCLUSIONS

These data show that coffee consumption increases the risk of CVE in a linear fashion in hypertension. This association may be explained in part by the association between coffee and development of hypertension. Hypertensive patients should be discouraged from drinking coffee.

Coffee Consumption Increases the Antioxidant Capacity of Plasma and Has No Effect on the Lipid Profile or Vascular Function in Healthy Adults in a Randomized Controlled Trial

BACKGROUND

Coffee, a source of antioxidants, has controversial effects on cardiovascular health.

OBJECTIVE

We evaluated the bioavailability of chlorogenic acids (CGAs) in 2 coffees and the effects of their consumption on the plasma antioxidant capacity (AC), the serum lipid profile, and the vascular function in healthy adults.

METHODS

Thirty-eight men and 37 women with a mean ± SD age of 38.5 ± 9 y and body mass index of 24.1 ± 2.6 kg/m(2) were randomly assigned to 3 groups: a control group that did not consume coffee or a placebo and 2 groups that consumed 400 mL coffee/d for 8 wk containing a medium (MCCGA; 420 mg) or high (HCCGA; 780 mg) CGA content. Both were low in diterpenes (0.83 mg/d) and caffeine (193 mg/d). Plasma caffeic and ferulic acid concentrations were measured by GC, and the plasma AC was evaluated with use of the ferric-reducing antioxidant power method. The serum lipid profile, nitric oxide (NO) plasma metabolites, vascular endothelial function (flow-mediated dilation; FMD), and blood pressure (BP) were evaluated.

RESULTS

After coffee consumption (1 h and 8 wk), caffeic and ferulic acid concentrations increased in the coffee-drinking groups, although the values of the 2 groups were significantly different (P < 0.001); caffeic and ferulic acid concentrations were undetectable in the control group. At 1 h after consumption, the plasma AC in the control group was significantly lower than the baseline value (-2%) and significantly increased in the MCCGA (6%) and HCCGA (5%) groups (P < 0.05). After 8 wk, no significant differences in the lipid, FMD, BP, or NO plasma metabolite values were observed between the groups.

CONCLUSIONS

Both coffees, which contained CGAs and were low in diterpenes and caffeine, provided bioavailable CGAs and had a positive acute effect on the plasma AC in healthy adults and no effect on blood lipids or vascular function. The group that did not drink coffee showed no improvement in serum lipid profile, FMD, BP, or NO plasma metabolites. This trial was registered at registroclinico.sld.cu as RPCEC00000168.

Coffee consumption and risk of hypertension in the Polish arm of the HAPIEE cohort study

BACKGROUND/OBJECTIVES

Coffee consumption has been hypothesized to be associated with blood pressure (BP), but previous findings are not homogeneous. The aim of this study was to evaluate the association between coffee consumption and the risk of developing hypertension.

SUBJECTS/METHODS

Data on coffee consumption, BP and use of anti-hypertensive medicament were derived from 2725 participants of the Polish arm of the HAPIEE project (Health, Alcohol and Psychosocial factors In Eastern Europe) who were free of hypertension at baseline and followed up for an average of 5 years. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated by multivariate logistic regression analyses and stratified for potential confounding factors.

RESULTS

Coffee consumption was related to decreased age, smoking status and total energy intake. Compared with persons who drink <1 cup coffee per day, systolic BP was significantly associated with coffee consumption and the risk of hypertension was lower for individuals consuming 3-4 cups per day. Despite the analysis stratified by gender showed that the protective effect of coffee consumption on hypertension was significant only in women, the analysis after stratification by smoking status revealed a decreased risk of hypertension in non-smokers drinking 3-4 cups of coffee per day in both sexes (OR 0.41, 95% CI: 0.21, 0.79 for men and OR 0.54, 95% CI: 0.29, 0.99 for women). Upper category coffee consumption (>4 cups per day) was not related to significant increased risk of hypertension.

CONCLUSIONS

Relation between coffee consumption and incidence of hypertension was related to smoking status. Consumption of 3-4 cups of coffee per day decreased the risk of hypertension in non-smoking men and women only.

From sodium intake restriction to nitrate supplementation: Different measures with converging mechanistic pathways?

Endothelial nitric oxide synthase is at the centre of endothelial physiology producing nitric oxide which dilates blood vessels, inhibits platelet aggregation and smooth muscle cell proliferation and reduces adhesion molecule production. The laminar shear stress is a common test used usually as the flow mediated dilatation test (FMD) which is sensitive to saturated fat, sodium and potassium although with the latter ion it is possible potassium has direct effects on ion channels in the smooth muscle cell as well as the endothelial cell. High blood pressure and blood cholesterol both reduce nitric oxide production, the latter probably by increasing caveolin-1 which binds nitric oxide synthase. Saturated fat reduces nitric oxide by elevating LDL cholesterol and caveolin-1 while insulin stimulates nitric oxide synthase activity by serine phosphorylation. Polyphenols from tea, coffee and cocoa and virgin olive oil enhance FMD and eNOS activity is essential for this activity. Wine polyphenols produce mixed results and it is not clear at present that they are beneficial. Blackberries and other polyphenol-rich fruit also enhance FMD. Dietary nitrate from beetroot and green leafy vegetables is converted to nitrite by salivary microbes and then to nitric oxide and this acts directly on the smooth muscle to lower blood pressure particularly in a low oxygen environment. Dietary nitrate also improves work efficiency and improves flow mediated dilatation.

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

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

A Rapid Method to Evaluate Cardiac Repolarization Changes: The Effect of Two Coffee Strengths on the QT Interval

Objectives: To assess the effect of coffee on ventricular repolarization as measured by an electrocardiogram. Methods: Fifty-four healthy volunteers (34 males and 20 females, age 23 ± 5 years) received 1 cup of coffee (caffeine content 120 mg) and 11 participants received 2 cups. Blood pressure and heart rate were measured prior to coffee and every hour thereafter for 5 h. A 12-lead digital Holter recorded continuously, and RR, QT, and QTc intervals were obtained every 30 min. Results: Following coffee, RR increased from 802 ± 102 to 873 ± 126 ms (p = 0.001), QT increased from 359 ± 26 to 367 ± 27 ms at 1.5 h (p = 0.047), and QTc decreased from 387 ± 21 to 381 ± 23 ms at 30 min (p = 0.001), with no changes noted at other time points. Caffeine users and caffeine-naive subjects did not differ in QTc effects (p = 0.971). Females had longer QTc at each time point than males (p = 0.037), but neither had QTc prolongation following coffee. The heart rate decreased from 73 ± 9 to 69 ± 11 bpm at 1 h (p = 0.018), and no significant changes in blood pressure were noted. The effects of 1 or 2 cups of coffee did not differ in terms of QTc (p = 0.663), heart rate (p = 0.161), diastolic (p = 0.250), or systolic blood pressure (p = 0.168). Conclusion: Neither 1 nor 2 cups of coffee increased ventricular repolarization.

Espresso coffee consumption and risk of coronary heart disease in a large Italian cohort

Background

The relationship between coffee consumption and coronary heart disease (CHD) has been investigated in several studies with discrepant results. We examined the association between Italian-style (espresso and mocha) coffee consumption and CHD risk.

Methods

We investigated 12,800 men and 30,449 women without history of cardiovascular disease recruited to the EPICOR prospective cohort study. Coffee consumption was assessed at baseline. In a random sub-cohort of 1472 subjects, plasma triglycerides, and total, LDL and HDL cholesterol were determined to investigate the effect of coffee consumption on plasma lipids.

Results

After a mean follow up of 10.9 years, 804 cases of CHD (500 acute events, 56 fatal events and 248 revascularizations, all first events) were identified. Multivariable adjusted hazard ratios for CHD were: 1.18 (95% CI 0.87–1.60) for drinking 1–2 cups/day, 1.37 (95% CI 1.03–1.82) for >2–4 cups/day and 1.52 (95% CI 1.11–2.07) for over 4 cups/day (P trend <0.001) compared to reference (<1 cup/day). Plasma triglycerides, and total, LDL and HDL cholesterol did not vary significantly (ANOVA) with coffee consumption.

Conclusion

Consumption of over 2 cups/day of Italian-style coffee is associated with increased CHD risk, but coffee consumption was not associated with plasma lipid changes, so the adverse effect of consumption appears unrelated to lipid profile.