Habitual coffee consumption and blood pressure: an epidemiological perspective

Coffee consumption and cardiometabolic health: a comprehensive review of the evidence

This review provides a comprehensive synthesis of longitudinal observational and interventional studies on the cardiometabolic effects of coffee consumption. It explores biological mechanisms, and clinical and policy implications, and highlights gaps in the evidence while suggesting future research directions. It also reviews evidence on the causal relationships between coffee consumption and cardiometabolic outcomes from Mendelian randomization (MR) studies. Findings indicate that while coffee may cause short-term increases in blood pressure, it does not contribute to long-term hypertension risk. There is limited evidence indicating that coffee intake might reduce the risk of metabolic syndrome and non-alcoholic fatty liver disease. Furthermore, coffee consumption is consistently linked with reduced risks of type 2 diabetes (T2D) and chronic kidney disease (CKD), showing dose-response relationships. The relationship between coffee and cardiovascular disease is complex, showing potential stroke prevention benefits but ambiguous effects on coronary heart disease. Moderate coffee consumption, typically ranging from 1 to 5 cups per day, is linked to a reduced risk of heart failure, while its impact on atrial fibrillation remains inconclusive. Furthermore, coffee consumption is associated with a lower risk of all-cause mortality, following a U-shaped pattern, with the largest risk reduction observed at moderate consumption levels. Except for T2D and CKD, MR studies do not robustly support a causal link between coffee consumption and adverse cardiometabolic outcomes. The potential beneficial effects of coffee on cardiometabolic health are consistent across age, sex, geographical regions, and coffee subtypes and are multi-dimensional, involving antioxidative, anti-inflammatory, lipid-modulating, insulin-sensitizing, and thermogenic effects. Based on its beneficial effects on cardiometabolic health and fundamental biological processes involved in aging, moderate coffee consumption has the potential to contribute to extending the healthspan and increasing longevity. The findings underscore the need for future research to understand the underlying mechanisms and refine health recommendations regarding coffee consumption.

Enjoy or quit: impact of coffee on cardiac and metabolic health

Coffee is one of the most consumed beverages worldwide. The effects of coffee on the body are primarily attributed to its key active ingredient, caffeine, a methylxanthine derivative with stimulant effects. However, coffee contains over one hundred bioactive compounds apart from caffeine, such as phenolic compounds, chlorogenic acids, tannin, thiamin, spermidine, quinides, trigonelline, lignins, and minerals like potassium and magnesium, all of which may contribute to its effects on the body. Each of these compounds may have beneficial effects. A common misconception is that coffee consumption should be avoided, especially by those with cardiovascular problems. However, recent data support the safety of moderate habitual consumption of two to three cups of coffee per day. Furthermore, this moderate regular consumption is associated with reduced cardiovascular mortality, lower blood pressure, and improved metabolic state. Many recent studies report additional medical benefits associated with coffee consumption. In this article, we review recent literature on the cardiometabolic effects of regular coffee drinking, including its impact on cardiac arrhythmia, blood pressure, and glucose and lipid metabolism. To sum up the medical evidence in the literature, individuals who drink modest amounts of coffee should feel comfortable continuing to enjoy it, provided they do not experience adverse effects.

The Effects of Caffeine on Blood Platelets and the Cardiovascular System through Adenosine Receptors

Caffeine is the most popular and widely consumed behaviourally active substance in the world. This review describes the influence of caffeine on the cardiovascular system, with a special focus on blood platelets. For many years, caffeine was thought to have a negative effect on the cardiovascular system mainly due to increasing blood pressure. However, more recent data suggest that habitual caffeine consumption may reduce the risk of cardiovascular disease and hypertension. This could be a significant finding as cardiovascular disease is the leading cause of death worldwide. Caffeine is known to inhibit A1 adenosine receptors, through which it is believed to modulate inter alia coronary blood flow, total peripheral resistance, diuresis, and heart rate. It has been shown that coffee possesses antiplatelet activity, but depending on the dose and the term of its use, caffeine may stimulate or inhibit platelet reactivity. Also, chronic exposure to caffeine may sensitize or upregulate the adenosine receptors in platelets causing increased cAMP accumulation and anti-aggregatory effects and decrease calcium levels elicited by AR agonists. The search for new, selective, and safe AR agonists is one of the new strategies for improving antiplatelet therapy involving targeting multiple pathways of platelet activation. Therefore, this review examines the AR-dependent impact of caffeine on blood platelets in the presence of adenosine receptor agonists.

Association of caffeine consumption with all-cause and cause-specific mortality in adult Americans with hypertension

Coffee is an important beverage that is widely consumed, of which caffeine is the main active ingredient. However, the long-term relationship between caffeine consumption and mortality in hypertensive patients has rarely been studied. This study analyzed a cohort of 12,093 US adults from the National Health and Nutrition Examination Survey from 1999 to 2018. Caffeine consumption was divided into five groups: no intake, >0 to ≤100, >100 to ≤300, >300 to ≤400 and >400 mg/day. Using multivariable-adjusted Cox proportional hazards models, this study performed a 20-year follow-up analysis (1999-2018). In the fully adjusted model, all caffeine consumers had lower all-cause mortality compared with no intake, especially in the >300 to ≤400 mg/day group (hazard ratio (HR) 0.71, 95% confidence interval (CI) 0.60-0.84). The result of restricted cubic spline also showed a nonlinear association between caffeine consumption and all-cause mortality. For cardiovascular disease, mortality decreased only at >400 mg/day (HR 0.63, 95% CI 0.47-0.85). For cancer, diabetes, and kidney disease, only >300 to ≤400 mg/day was significantly associated with decreased mortality: (HR 0.60, 95% CI 0.42-0.67), (HR 0.22, 95% CI 0.07-0.75), and (HR 0.32, 95% CI 0.10-0.96), respectively. Lower all-cause mortality was observed in non-Hispanic White, African American, population aged 40 or above, and people with a body mass index <25 kg/m2. Our findings indicate a nonlinear association between average caffeine consumption and all-cause mortality, suggesting that hypertensive patients may benefit from moderate caffeine intake.

The effects of caffeine supplementation on blood pressure in adults: A systematic review and dose-response meta-analysis

BACKGROUND AND AIMS

Hypertension is a serious complication linked to a higher risk for organs. Caffeine is a natural component that affects the cardiovascular system, while the mechanisms of its effects are not fully established. Therefore, we aimed to examine the impact of caffeine supplementation on blood pressure (BP) by conducting a systematic review and dose-response meta-analysis of randomized controlled clinical trials (RCTs).

METHODS AND RESULTS

We searched online databases using relevant keywords up to July 2022 to identify RCTs using caffeine on systolic (SBP) and diastolic BP (DBP) in adults. Inclusion criteria were adult participants ≥18 years old for subjects, examining the effect of caffeine supplementation on BP, and RCTs studies. A random-effects model was used to estimate the weighted mean difference (WMD) and 95% confidence (CI). The pooled of 11 effect sizes analysis of 8 studies demonstrated significant increases in SBP (WMD:1.94 mmHg; 95%CI:0.52, 3.35; p = 0.007) and DBP (WMD:1.66 mmHg; 95% CI:0.75, 2.57; p = 0.000) after caffeine supplementation. The subgroup analysis showed that caffeine supplementation more effectively increased SBP and DBP in males than females. Moreover, meta-regression analysis demonstrated a significant relationship between the dose of caffeine intake and changes in SBP (p = 0.000), DBP (p = 0.000), and duration of the trial in SBP (p = 0.005), and DBP (p = 0.001). The non-linear dose-response analysis detected the dosage of supplementation >400 mg/day is effective for increasing DBP (p = 0.034), and the duration of supplementation of more than nine weeks makes increasing in both SBP and DBP.

CONCLUSION

This meta-analysis shows that caffeine supplementation significantly increased SBP and DBP in adults.

Current therapeutic targets and multifaceted physiological impacts of caffeine

Caffeine, which shares consubstantial structural similarity with purine adenosine, has been demonstrated as a nonselective adenosine receptor antagonist for eliciting most of the biological functions at physiologically relevant dosages. Accumulating evidence supports caffeine's beneficial effects against different disorders, such as total cardiovascular diseases and type 2 diabetes. Conversely, paradoxical effects are also linked to caffeine ingestion in humans including hypertension-hypotension and tachycardia-bradycardia. These observations suggest the association of caffeine action with its ingested concentration and/or concurrent interaction with preferential molecular targets to direct explicit events in the human body. Thus, a coherent analysis of the functional targets of caffeine, relevant to normal physiology, and disease pathophysiology, is required to understand the pharmacology of caffeine. This review provides a broad overview of the experimentally validated targets of caffeine, particularly those of therapeutic interest, and the impacts of caffeine on organ-specific physiology and pathophysiology. Overall, the available empirical and epidemiological evidence supports the dose-dependent functional activities of caffeine and advocates for further studies to get insights into the caffeine-induced changes under specific conditions, such as asthma, DNA repair, and cancer, in view of its therapeutic applications.

Effect of Caffeine in Hypertension

Hypertension (HTN) is characterized by an elevated arterial blood pressure with no apparent symptom while proving to be a crucial risk factor for the other underlying disorders such as cardiac failure, atrial fibrillation, stroke and various others, steering to recurrent premature deaths worldwide if left untreated. There are innumerate factors responsible for causing HTN such as age factor, obesity, inheritance, physical inactivity, stress, and unhealthy diet whereas some therapeutics and pharmaceuticals may too trigger this condition notably caffeine. As caffeine is amongst the most widely consumed drinks worldwide and hence an ordeal to cease its use, accordingly this review article in-sighted to raise cognizance specifically towards the action of caffeine affiliated with HTN. Therefore, this review is focused on the risk factors and preventive measures associated with HTN, especially the role of caffeine in inducing HTN as to create social awareness regarding how the excessive habituated caffeine consumption may aggravate this condition.

Uncontrolled blood pressure and associated factors in adult hypertensive patients undergoing follow-up at public health facility ambulatory clinics in Bishoftu town, Ethiopia: a multi-center study

BACKGROUND

Uncontrolled blood pressure is an important medical and public health problem in developing countries like Ethiopia. Improving the management of hypertension requires a better comprehension of the factors influencing blood pressure control and the application of interventions. But in clinical practice, blood pressure is still not adequately controlled. Thus, this study aimed to assess uncontrolled blood pressure and associated among adult hypertensive patients on follow-up at public health facility ambulatory clinics in Bishoftu, Ethiopia.

METHODS

A hospital-based cross-sectional study was conducted among 398 adult hypertensive patients who were on treatment and follow-up from April to May 31, 2022. Systematic random sampling was used to select study participants. Data were collected using an interviewer-administered, semi-structured questionnaire and chart review. The Eighth Joint National Committee (JNC 8) criteria was applied to define blood pressure control status. Binary logistic regression analysis was used to model the association between dependent and independent variables. An adjusted odds ratio and 95% confidence interval were used to measure the strength of the association. Finally, at a p-value < 0.05, statistical significance was proclaimed.

RESULT

Of the total study participants, 249(62.6%) were male. The mean age was 62.26 ± 11.55 years. The overall proportion of uncontrolled blood pressure was 58.8% (95% CI: 54-64). Salt intake (AOR = 2.51; 95% CI: 1.49-4.24), lack of physical activity (AOR = 1.40; 95% CI: 1.10-2.62), habitual coffee consumption (AOR = 4.52; 95% CI: 2.67-7.64), higher BMI (AOR = 2.08; 95% CI: 1.24-3.49), and non-adherence to antihypertensive medications (AOR = 2.31; 95% CI: 1.3-3.89) were independent predictors of uncontrolled blood pressure.

CONCLUSION

More than half of the hypertensive patients in this study had uncontrolled blood pressure. Healthcare providers and other accountable stakeholders should urge patients to follow salt restriction, physical activity, and antihypertensive medication regimes. Reduced coffee consumption and weight maintenance are other crucial blood pressure control measures.

Coffee and Green Tea Consumption and Cardiovascular Disease Mortality Among People With and Without Hypertension

Background This study was conducted to examine the impacts of coffee and green tea consumption on cardiovascular disease (CVD) mortality among people with severe hypertension. Methods and Results In the JACC (Japan Collaborative Cohort Study for Evaluation of Cancer Risk), 18 609 participants (6574 men and 12 035 women) aged 40 to 79 years at baseline who completed a lifestyle, diet, and medical history questionnaire, and health examinations, were followed up until 2009. We classified the participants into four blood pressure (BP) categories: optimal and normal BP, high-normal BP, grade 1 hypertension, and grade 2-3 hypertension. A Cox proportional hazard model was used to calculate the multivariable hazard ratios with 95% CIs of CVD mortality. During the 18.9 years of median follow-up, a total of 842 CVD deaths were documented. Coffee consumption was associated with an increased risk of CVD mortality among people with grade 2-3 hypertension; the multivariable hazard ratios (95% CI) of CVD mortality were 0.98 (0.67-1.43) for <1 cup/day, 0.74 (0.37-1.46) for 1 cup/day, and 2.05 (1.17-3.59) for ≥2 cups/day, compared with non-coffee drinkers. Such associations were not found among people with optimal and normal, high-normal BP, and grade 1 hypertension. Green tea consumption was not associated with an increased risk of CVD across any BP categories. Conclusions Heavy coffee consumption was associated with an increased risk of CVD mortality among people with severe hypertension, but not people without hypertension and with grade 1 hypertension. In contrast, green tea consumption was not associated with an increased risk of CVD mortality across all categories of BP.

Beyond thirst: Cravings for non-alcoholic beverages including soft drink

Cravings for a range of substances including drugs, alcohol, and food have been shown to predict subsequent consumption or use. However, this link has not yet been systematically examined for beverages other than alcohol. The present study aimed to provide a comprehensive investigation of cravings for non-alcoholic beverages and their link to consumption. Participants were 128 undergraduate students (17-25 years) who completed a craving diary and daily consumption measure over a period of a week. Cravings were reported for a range of beverages, including tea, juice, and flavoured milk, but by far the most craved beverages were water, coffee, and soft drink. Stronger cravings were associated with a greater likelihood of drinking and drinking more of the craved beverage. This was particularly the case for soft drink. Unlike water, cravings for coffee and soft drink were triggered by factors other than thirst, and the number of cravings predicted the total amount drunk over the week. The findings demonstrate the existence of cravings for non-alcoholic beverages such as soft drink, and point to these cravings as a potential target for reducing consumption.

Differences in Nutritional and Psychological Habits in Hypertension Patients

Multifactorial factors such as psychological and nutritional habits are controlling factors in hypertension. The aim of the present study was to analyze differences in nutritional and psychological habits in humans with hypertension. Fifty participants with hypertension (HG) (57.5 ± 13.6 years) and 100 participants as control group (CG) with no hypertension disease (48.9 ± 7.9 years) were interviewed via online questionnaire. Multifactorial items in nutrition habits and psychological profile were analyzed by a compendium of questionnaires; psychological measures refer to personality, anxiety, depression, loneliness, perceived stress, and psychological inflexibility; and a nutritional questionnaire to analyze eating habits and nutrition behaviors of the participants. CG showed significantly higher week vitality (p = 0.001), juice weekly consumption (p = 0.011), coffee weekly consumption (p = 0.050), fermented milk weekly consumption (p = 0.004), and fruit weekly consumption (p = 0.022) than HG. Lower values of weekly coffee consumption and week vitality were found in HG. According to the psychological profile, significant differences were found only depression values, finding HG more depressed than CG (p = 0.002). In conclusion, our results showed that people with better nutrition and mental health would present lower levels of blood pressure. Therefore, the combination of psychological therapy and nutritional recommendations for reducing the risk of having hypertension and improving the blood pressure levels may be needed for patient with hypertension.

Coffee Consumption and Blood Pressure: Results of the Second Wave of the Cognition of Older People, Education, Recreational Activities, Nutrition, Comorbidities, and Functional Capacity Studies (COPERNICUS)

This study examined the relationship between the frequency of coffee consumption and blood pressure over a two year follow up of a cohort of elderly people. Healthy, older people (N = 205) were examined at baseline and at two years. Participants completed physical and behavioural assessments, which included body composition, current pharmacological treatment, and frequency of coffee consumption grouped into three categories: “never to a few times per month”, “once a week to a few times per week”, and “every day”. Blood pressure (systolic (sBP), diastolic (dBP), mean (mBP), and pulse pressure (PP)) was measured at baseline and after two years. After adjusting for body composition, smoking status, age, sex, heart rate, and number of antihypertensive agents taken, participants who drank coffee everyday had a significant increase in sBP, with a mean of 8.63 (1.27; 15.77) and an mBP, with a mean of 5.55 mmHg (0.52; 10.37) after two years (t = 2.37, p = 0.02 and t = 2.17, p = 0.03, respectively) compared to participants who never or very rarely (up to a few times per month) drank coffee. DBP and PP were not affected by coffee consumption frequency in a statistically significant manner.

Association between hypertension and coffee drinking based on CYP1A2 rs762551 single nucleotide polymorphism in Taiwanese

Background

Hypertension increases the likelihood of cardiovascular diseases (CVDs). Cytochrome P450 1A2 (CYP1A2) single nucleotide polymorphism (SNP) is related to caffeine metabolism and the risk of CVD among coffee drinkers. CYP1A2 rs762551 influenced the risk of stroke among hypertensive patients. We examined the relationship between hypertension and coffee drinking based on CYP1A2 rs762551 SNP in Taiwanese adults.

Methods

We used data contained in the Taiwan Biobank database (2011–2018) and included 19,133 participants having complete information on hypertension, rs762551 polymorphism, coffee intake, etc. The risk of hypertension was determined using multiple logistic regression.

Results

Coffee intake was significantly associated with a lower risk of hypertension. The odds ratio (OR), 95% confidence interval (CI), and p-value were 0.877, 0.807–0.954, and 0.0032, respectively. CYP1A2 rs762551 was not significantly associated with the risk of hypertension, but it had a significant interactive association with coffee drinking (p value = 0.0303). After stratification by rs762551 genotypes, the inverse coffee drinking-hypertension association was retained, but significant results were observed only in those with the AC + CC genotype (OR 0.678, 95% CI 0.722–900, p value = 0.0001). According to the combination of coffee drinking and rs762551 genotypes (reference group: no coffee drinking and rs762551 AA), the coffee drinking-AC + CC group had a lower risk of hypertension (OR 0.888, 95% CI 0.789–0.999, p value = 0.0483).

Conclusion

Coffee drinking, particularly among individuals with the CYP1A2 rs762551 AC + CC genotype was associated with lower odds of hypertension.

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.

Habitual coffee and caffeinated beverages consumption is inversely associated with arterial stiffness and central and peripheral blood pressure

The effects of chronic coffee consumption on the cardiovascular system are still under debate. Aortic stiffness, wave reflections, and central and peripheral blood pressure (BP) are milestone indicators of cardiovascular-risk. We sought to investigate the association between coffee and caffeine consumption, arterial stiffness, and central/peripheral BP. Aortic stiffness was evaluated via pulse wave velocity (PWV); wave reflections with the augmentation index (AIx);peripheral systolic BP (SBP), diastolic BP (DBP), and central BP (cSBP/cDBP) were non-invasively assessed. Coffee and caffeine consumption was ascertained using a questionnaire. A linear inverse relationship between coffee and caffeine consumption and arterial stiffness and central and peripheral BP was found.Light coffee and caffeine consumers showed β-coefficients for PWV-0.15, SBP-3.61, DBP-2.48, cSBP-3.21, and cDBP-2.18 (all p values < 0.05).Present findings suggest that coffee and caffeine consumption is inversely associated with arterial stiffness and central and peripheral BP in a large population sample. Interventional prospective studies are needed to demonstrate the causal association.

Effects of Caffeine on Brown Adipose Tissue Thermogenesis and Metabolic Homeostasis: A Review

The impact of brown adipose tissue (BAT) metabolism on understanding energy balance in humans is a relatively new and exciting field of research. The pathogenesis of obesity can be largely explained by an imbalance between caloric intake and energy expenditure, but the underlying mechanisms are far more complex. Traditional non-selective sympathetic activators have been used to artificially elevate energy utilization, or suppress appetite, however undesirable side effects are apparent with the use of these pharmacological interventions. Understanding the role of BAT, in relation to human energy homeostasis has the potential to dramatically offset the energy imbalance associated with obesity. This review discusses paradoxical effects of caffeine on peripheral adenosine receptors and the possible role of adenosine in increasing metabolism is highlighted, with consideration to the potential of central rather than peripheral mechanisms for caffeine mediated BAT thermogenesis and energy expenditure. Research on the complex physiology of adipose tissue, the embryonic lineage and function of the different types of adipocytes is summarized. In addition, the effect of BAT on overall human metabolism and the extent of the associated increase in energy expenditure are discussed. The controversy surrounding the primary β-adrenoceptor involved in human BAT activation is examined, and suggestions as to the lack of translational findings from animal to human physiology and human in vitro to in vivo models are provided. This review compares and distinguishes human and rodent BAT effects, thus developing an understanding of human BAT thermogenesis to aid lifestyle interventions targeting obesity and metabolic syndrome. The focus of this review is on the effect of BAT thermogenesis on overall metabolism, and the potential therapeutic effects of caffeine in increasing metabolism via its effects on BAT.

Metabolic syndrome and lifestyle factors among type 2 diabetes mellitus patients in Dessie Referral Hospital, Amhara region, Ethiopia

Background

The prevalence of metabolic syndrome is rising at an alarming rate and more common among Type 2 Diabetes Mellitus patients in the world. The risk for cardiovascular disease is greater among individuals who have a combination of Type 2 Diabetes Mellitus and metabolic syndrome compared to those who have either alone.

Objective

To assess the proportion of metabolic syndrome and lifestyle factors among Type 2 Diabetes Mellitus Patients in Dessie Referral Hospital, Amhara Region, Ethiopia.

Methods

A hospital-based cross-sectional study was conducted from February to March 2017 among 343 randomly selected Type 2 Diabetes Mellitus patients. Three definitions of Metabolic syndrome were considered. Multivariable logistic regression analysis was conducted to identify factors associated with metabolic syndrome. Adjusted odds ratio (AOR) with 95% confidence intervals (CI) were reported to show the strength of association. Statistical significance was declared at P-value < 0.05.

Result

The proportion of metabolic syndrome was 50.3%, 59.4% and 64.5% according to 2005 International Diabetes Federation, revised ATP III and 2009 harmonized criteria, respectively. Being female (AOR = 2.43; 95% CI = 1.40, 4.21), consumption of red meat (AOR = 2.61; 95% CI = 1.28, 5.33), sedentary leisure time activity (AOR = 2.65; 95% CI = 1.47, 4.78), coffee intake (AOR = 0.43; 95% CI = 0.21, 0.86), BMI ≥ 25 kg/m² (AOR = 9.59; 95% CI = 4.98, 18.47), 40–49 years of age (AOR = 2.74, 95% CI = (1.02, 7.37), 50–59 years of age (AOR = 4.22; 95% CI = 1.60, 11.11) and ≥70 years of age (AOR = 4.51, 95% CI = 1.44, 14.15) were significantly associated with metabolic syndrome.

Conclusion and recommendation

The proportion of metabolic syndrome was high among Type 2 Diabetes Mellitus patients. Overweight and obesity, being female, age of respondent, intake of coffee, regular red meat consumption, and sedentary leisure-time activity were factors associated with metabolic syndrome. Counseling of Type 2 Diabetes Mellitus patients on the need for spending leisure time with activities, intake of coffee, control of body weight, and avoidance of regular red meat consumption is recommended.

Multilevel Analysis of 24-Hour Blood Pressure, Heart Rate, and Associated Factors among Police Officers in Hanoi, Vietnam

Background

Due to long-hour outdoor working environment, policemen have been subjected to tremendous health risks including blood pressure (BP) and heart rate (HR). In tropical countries, the temperature is extremely harsh which may get peak at above 40 Celsius degrees or drops under 8 Celsius degrees. However, the existing data on the effects of weather variation on BP and HR among police task force has been scarce in Vietnam.

Aims

This study aimed to describe the variation of 24-hour BP and HR and identify factors associated with BP and HR for further appropriate interventions in order to reduce health risks from occupational exposure.

Methods

Multilevel regression analysis (MLRA) was applied with two levels of influent factors. 24-hour holter measured systolic blood pressure (SBP), diastolic blood pressure (DBP), and HR values were the first level which should then be nested in the second level (individual). 24-hour temperature and humidity variations were extracted, respectively, from Hanoi Hydrometeorology Department. All individual characteristics and risk behaviours were measured within 24 studying hours.

Results

Temperature and humidity were major factors that influenced (74%-78%) the variation of BP and HR among the policemen population. When each of the Celsius degree temperature or percentage humidity increases, the SBP goes down by 0.44 (0.11-0.77) and by 0.2 (0.33-0.77), respectively, and the DBP goes down by 0.21 (-0.05-0.48) and by 0.12 (0.02-0.22), respectively, and vice versa. Interaction between temperature and humidity was significantly influent to SBP. The farther the time section from the first time section (0-6AM) the more the variation of the BP and HR. Transition from winter to summer made SBP and DBP decrease and vice versa. Individual characteristics including body mass index (BMI), bad life styles, and stress contributed 22% to 26% to the variation of BP and HR. Traffic policemen were at the greatest risks of the outdoor ambient variation in comparison with the firefighters and office-based policemen.

Conclusion

Designing and equipping appropriate uniform and outdoor facilities could help to reduce influence of temperature and humidity variation in the outdoor workplace. Besides, training and educating programs that aimed at controlling BMI, risk behaviours, and stress for police taskforce, especially the traffic policemen, should be implemented.

Caffeine and Exercise: What Next?

Caffeine is a widely utilized performance-enhancing supplement used by athletes and non-athletes alike. In recent years, a number of meta-analyses have demonstrated that caffeine's ergogenic effects on exercise performance are well-established and well-replicated, appearing consistent across a broad range of exercise modalities. As such, it is clear that caffeine is an ergogenic aid-but can we further explore the context of this ergogenic aid in order to better inform practice? We propose that future research should aim to better understand the nuances of caffeine use within sport and exercise. Here, we propose a number of areas for exploration within future caffeine research. These include an understanding of the effects of training status, habitual caffeine use, time of day, age, and sex on caffeine ergogenicity, as well as further insight into the modifying effects of genotype. We also propose that a better understanding of the wider, non-direct effects of caffeine on exercise, such as how it modifies sleep, anxiety, and post-exercise recovery, will ensure athletes can maximize the performance benefits of caffeine supplementation during both training and competition. Whilst not exhaustive, we hope that the questions provided within this manuscript will prompt researchers to explore areas with the potential to have a large impact on caffeine use in the future.

Association between Dietary Intakes of Tea, Coffee, and Soft Drinks in Patients Undergoing Coronary Angiography with Coronary Artery Stenosis

Background:

Coronary artery disease (CAD) is one of the major causes of mortality that is related to the nutritional habits and lifestyle. The aim of this study was to examine the association between tea, coffee, and soft drink consumption and coronary artery stenosis in patients undergoing coronary angiography.

Methods:

Out of all the patients, 208 cases (101 Female) with 57.81 ± 12.18 (mean ± SD) were assigned to participate in this cross-sectional study. In total, 168-items, semi-quantitative food frequency questionnaire collected for assessments of dietary intakes of black tea, coffee, caffeine, and soft drinks and record demographic and clinical questionnaire.

Results:

There were negative association between arteries with stenosis of more than 50% number with dietary intakes of tea (P = 0.011, r = – 0.187), coffee (P = 0.069, r = – 0.098) intakes, and dietary caffeine intake (P = 0.043, r = –0.118). The high consumptions of soft drinks (P = 0.005, r = 0.387) were associated with an enhancement in arteries with stenosis of more than 50% number. In addition, dietary consumption of black tea have a negatively significant association with the history of previous angiography (P = 0.044, r = –0.121), the history of previous Stanton (P = 0.035, r = –0.132), and coronary artery bypass graft surgery nomination (P = 0.008, r = –0.216). Coffee consumption showed a significant negative relationship with engagement for coronary artery bypass graft surgery (P = 0.004, r = –0.598).

Conclusions:

Dietary intakes of tea, coffee, and caffeine may have a negative relationship with CAD and cardio vascular diseases. Healthy dietary lifestyle is an important issue for the prevention of chronic diseases.

Age Modulates the Association of Caffeine Intake With Cognition and With Gray Matter in Elderly Diabetics

BACKGROUND

The association between caffeine and cognitive performance has not been tested in older individuals with type 2 diabetes (T2D). Its association with brain volume in T2D has been tested only in animals.

METHODS

We examined the association of caffeine with cognitive function and brain volume in a sample of elderly diabetics participating in the Israel Diabetes and Cognitive Decline Study (n = 638) and the moderating effect of age on this association. In a subsample (n = 185) with magnetic resonance imaging, we also examined these associations with gray and white matter volumes (GM/WM).

RESULTS

Using linear regression adjusting for cognition-related covariates, we found that higher caffeine intake was associated with better function in overall cognition (p = .018), attention/working memory (p = .002), executive functioning (p = .047), and semantic categorization (p = .026). Interaction analyses of caffeine intake with age were significant for semantic categorization (p = .025), and approached significance for overall cognition (p = .066). This association was driven by the older group (above-median) for whom the association of caffeine intake with semantic categorization (p = .001), attention/working memory (p = .007), executive functioning (p = .005), and overall cognition (p = .002) were significant. In the magnetic resonance imaging subsample, there was an interaction (p = .034) of caffeine intake with age for GM volume; in the older group, higher caffeine intake was associated with greater GM volume (β = .198, p = .033).

CONCLUSIONS

Caffeine intake may have a beneficial role in cognitive functioning of elderly adults with T2D, which may be moderated by age. Greater GM volume may be a mechanism underlying the association of higher caffeine intake with better cognitive function.

Elemental analysis of Brazilian coffee with ion beam techniques: From ground coffee to the final beverage

Brazilian coffee is well known worldwide due to its quality and richness in taste. The aim of the present study is to provide the elemental characterization of Brazilian coffee along different stages of the drip brewing process. To that end, samples from roasted ground coffee, spent coffee, paper filters and the final beverage were analyzed with one single ion beam technique, namely particle-induced X-ray emission (PIXE). In total, over 140 samples from 8 different Brazilian brands of ground coffee were analyzed. Large differences in some elemental concentrations were observed among different brands and among different batches of a single brand, which leads to high variances in the data. Concerning the beverage preparation, the analysis of the spent coffee shows that the transfer ratio from the ground coffee to the beverage differs for each element. Our results indicate that potassium and chlorine have the highest transfer ratio. Moreover, the concentration of rubidium is relatively high in drinking coffee. Finally, there is no influence of the elemental composition of paper filter in the preparation of drinking coffee.

Effects of Coffee Intake on Incident Chronic Kidney Disease: A Community-Based Prospective Cohort Study

BACKGROUND

Drinking coffee can raise public health problems, but the association between coffee and kidney disease is unknown. We studied whether coffee intake can affect the development of chronic kidney disease in the general population.

METHODS

We analyzed 8717 subjects with normal renal function recruited from the Korean Genome and Epidemiology Study (KoGES) cohort. Based on a food frequency questionnaire, coffee consumption was categorized into 5 groups: 0 per week, <1 cup per week, 1-6 cups per week, 1 cup per day, and ≥2 cups per day. The primary outcome was incident chronic kidney disease, defined as an estimated glomerular filtration rate <60 mL/min/1.73 m².

RESULTS

The mean age (standard deviation) of study subjects was 52.0 (8.8) years, and 47.8% were male. Among the subjects, 52.8% were daily coffee consumers. During a mean follow-up of 11.3 (range, 5.9-11.5) years, 9.5% of participants developed chronic kidney disease. The incident chronic kidney disease occurred less in daily coffee consumers. Unadjusted hazard ratios (HRs) was significantly lower in daily coffee consumers. In multivariable Cox model even after adjustment of blood pressure, hypertension, cardiovascular disease, diabetes, and amount of daily intake for caffeine-containing foods such as tea and chocolate, coffee consumers with 1 cup per day (HR, 0.76; 95% confidence interval, 0.63-0.92) and ≥2 cups per day (HR, 0.80; 95% confidence interval, 0.65-0.98) were associated with a lower risk of chronic kidney disease development than nondrinkers. Time-averaged and time-varying Cox models yielded similar results. The rates of decline in glomerular filtration were lower in daily coffee consumers.

CONCLUSIONS

Our findings suggest that daily coffee intake is associated with decreased risk of the development of chronic kidney disease.

Coffee consumption in hemodialysis patients: how many?

BACKGROUND AND AIMS

Coffee is one of the most widely consumed beverages worldwide. However, fluid intake restriction is an important and difficult challenge for hemodialysis (HD) patients. The aim of this study was to analyze the effect of coffee intake on hydration and nutritional parameters of HD patients.

METHODS

This was an observational, cross-sectional, multicenter study where 373 HD patients from 8 dialysis centers in Portugal were enrolled. A face-to-face questionnaire was applied and patient's clinical and body composition parameters were analyzed. The sample was divided into 3 groups depending on coffee intake: group 1-don't drink coffee, group 2-drink 1-2 coffees/day and group 3-drink 3 or more coffees/day. Laboratory and body composition parameters were registered in the month prior to the questionnaire application. Body composition was assessed with the Body Composition Monitor (BCM; Fresenius Medical Care Deutschland GmbH, Germany).

RESULTS

Patient's mean age was 67.2 ± 14.4 years and the mean HD vintage was 61.3 ± 56.2 months. Patients who reported drinking 3 or more coffees daily were younger, presented higher levels of potassium, phosphorus, diastolic BP, albumin and interdialytic weight gain (IDWG) and lower dialysis adequacy (Kt/V). Regarding body composition, patients in the group 3 showed higher body cell mass index (BCMI) and lean tissue index (LTI). On the other hand, the group 1 were the oldest, had a higher Kt/V, a lower diastolic blood pressure (BP) and potassium levels, whereas G2 presented a lower LTI, BCMI and IDWG.

CONCLUSIONS

Drinking 3 or more coffees daily increases the risk of a higher diastolic BP, potassium and IDWG in HD patients.

Effect of Green Coffee Consumption on Resting Energy Expenditure, Blood Pressure, and Body Temperature in Healthy Women: A Pilot Study

KEY TEACHING POINTS

• There are several findings, and chlorogenic acid may have antihypertensive effects. • There is a significant correlation between green coffee chlorogenic acid amount and REE. • Intracellular and extracellular liquid amounts decrease following green coffee consumption (215-280 mg caffeine), and these changes are observed in individuals whose usual dietary caffeine intake is relatively both low and high. • The body temperature values of individuals whose usual dietary caffeine intake was in the 50th percentile or greater (relatively high) increased after green coffee consumption.

Variable role of carotid bodies in cardiovascular responses to exercise, hypoxia and hypercapnia in spontaneously hypertensive rats

KEY POINTS

Carotid bodies play a critical role in maintaining arterial pressure during hypoxia and this has important implications when considering resection therapy of the carotid body in disease states such as hypertension. Curbing hypertension in patients whether resting or under stress remains a major global health challenge. We demonstrated previously the benefits of removing carotid body afferent input into the brain for both alleviating sympathetic overdrive and reducing blood pressure in neurogenic hypertension. We describe a new approach in rats for selective ablation of the carotid bodies that spares the functional integrity of the carotid sinus baroreceptors, and demonstrate the importance of the carotid bodies in the haemodynamic response to forced exercise, hypoxia and hypercapnia in conditions of hypertension. Selective ablation reduced blood pressure in hypertensive rats and re-set baroreceptor reflex function accordingly; the increases in blood pressure seen during exercise, hypoxia and hypercapnia were unaffected, abolished and augmented, respectively, after selective carotid body removal. The data suggest that carotid body ablation may trigger potential cardiovascular risks particularly during hypoxia and hypercapnia and that suppression rather than obliteration of their activity may be a more effective and safer route to pursue.

ABSTRACT

The carotid body has recently emerged as a promising therapeutic target for treating cardiovascular disease, but the potential impact of carotid body removal on the dynamic cardiovascular responses to acute stressors such as exercise, hypoxia and hypercapnia in hypertension is an important safety consideration that has not been studied. We first validated a novel surgical approach to selectively resect the carotid bodies bilaterally (CBR) sparing the carotid sinus baroreflex. Second, we evaluated the impact of CBR on the cardiovascular responses to exercise, hypoxia and hypercapnia in conscious, chronically instrumented spontaneously hypertensive (SH) rats. The results confirm that our CBR technique successfully and selectively abolished the chemoreflex, whilst preserving carotid baroreflex function. CBR produced a sustained fall in arterial pressure in the SH rat of ∼20 mmHg that persisted across both dark and light phases (P < 0.001), with baroreflex function curves resetting around lower arterial pressure levels. The cardiovascular and respiratory responses to moderate forced exercise were similar between CBR and Sham rats. In contrast, CBR abolished the pressor response to hypoxia seen in Sham animals, although the increases in heart rate and respiration were similar between Sham and CBR groups. Both the pressor and the respiratory responses to 7% hypercapnia were augmented after CBR (P < 0.05) compared to sham. Our finding that the carotid bodies play a critical role in maintaining arterial pressure during hypoxia has important implications when considering resection therapy of the carotid body in disease states such as hypertension as well as heart failure with sleep apnoea.

Coffee consumption and disease correlations

Coffee is one of the most widely consumed beverages in the world. It has primarily consumed due to its stimulant effect and unique taste since the ancient times. Afterwards, its consumption has been historically associated with a lower risk of some diseases such as type 2 diabetes mellitus, obesity, cardiovascular disease and some type of cancer and thus it has also consumed due to health benefits. It contains many bioactive compounds such as caffeine, chlorogenic acids and diterpenoid alcohols which have so far been associated with many potential health benefits. For example, caffeine reduces risk of developing neurodegenerative disease and chlorogenic acids (CGA) and diterpene alcohols have many health benefits such as antioxidant and chemo-preventive. Coffee also have harmful effects. For example, diterpenoid alcohols increases serum homocysteine and cholesterol levels and thus it has adverse effects on cardiovascular system. Overall, the study that supports the health benefits of coffee is increasing. But, it is thought-provoking that the association with health benefits of coffee consumption and frequency at different levels in each study. For this reason, we aimed to examine the health effect of the coffee and how much consumption is to investigate whether it meets the claimed health benefits.

Diet-independent relevance of serum uric acid for blood pressure in a representative population sample

A direct relationship between serum uric acid and blood pressure (BP) has been reported, but the possible confounding impact of diet on this association is unclear. The authors performed a cross-sectional analysis in the representative German Health Interview and Examination Survey for Adults (n=6788, aged 18-79 years). In adjusted regression models considering dietary factors, each 1-mg/dL higher uric acid value was associated with a 1.10-mm Hg (P=.0002) and a 0.60-mm Hg (P=.04) higher systolic BP among participants younger than 50 years and participants 50 years and older, respectively. For diastolic BP, uric acid was a significant predictor (β=0.71 mm Hg, P=.0001) among participants younger than 50 years and for participants 50 years and older without antihypertensive treatment. Adjusted odds ratios of hypertension for participants with hyperuricemia were broadly similar in younger (odds ratio, 1.71; P=.02) and older (odds ratio, 1.81; P=.0003) participants. Uric acid is a significant predictor of systolic BP and hypertension prevalence in the general adult population in Germany independently of several known dietary BP influences.

The Relationship Between Caffeine Intake and Immunological and Virological Markers of HIV Disease Progression in Miami Adult Studies on HIV Cohort

Although there are many studies on adverse health effects of substance use and HIV disease progression, similar studies about caffeine consumption are few. In this study, we investigated the effects of caffeine on immunological and virological markers of HIV disease progression. A convenience sample of 130 clinically stable people living with HIV/AIDS on antiretroviral therapy (65 consuming ≤250 mg/day and 65 consuming >250 mg/day of caffeine) were recruited from the Miami Adult Studies on HIV (MASH) cohort. This study included a baseline and 3-month follow-up visit. Demographics, body composition measures, substance use, Modified Caffeine Consumption Questionnaire (MCCQ), and CD4 count and HIV viral load were obtained for all participants. Multivariable linear regression and Linear Mixed Models (LMMs) were used to understand the effect of caffeine consumption on CD4 count and HIV viral load. The mean age of the cohort was 47.9 ± 6.4 years, 60.8% were men and 75.4% were African Americans. All participants were on ART during both the visits. Mean caffeine intake at baseline was 337.6 ± 305.0 mg/day and did not change significantly at the 3-month follow-up visit. Multivariable linear regressions after adjustment for covariates showed significant association between caffeine consumption and higher CD4 count (β = 1.532, p = 0.049) and lower HIV viral load (β = -1.067, p = 0.048). LMM after adjustment for covariates showed that the relationship between caffeine and CD4 count (β = 1.720, p = 0.042) and HIV viral load (β = -1.389, p = 0.033) continued over time in a dose-response manner. Higher caffeine consumption was associated with higher CD4 cell counts and lower HIV viral loads indicating beneficial effects on HIV disease progression. Further studies examining biochemical effects of caffeine on CD4 cell counts and viral replication need to be done in the future.

Update in Hypertension Therapy

Hypertension is the leading cause of early mortality in the world, and reduction of blood pressure can help to reduce that burden. There is an enormous and ever-expanding body of literature on hypertension, with a 2016 Medline search for hypertension retrieving more than 113,000 publications. Recent guidelines from major societies have been published, and often present conflicting recommendations based on the same data. Using a question-and-answer format, this article reviews some of the recent developments and opinions on management of blood pressure and provides practical suggestions for management in the clinical arena.

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.

Coffee and caffeine consumption and the risk of hypertension in postmenopausal women

BACKGROUND

The associations of coffee and caffeine intakes with the risk of incident hypertension remain controversial.

OBJECTIVE

We sought to assess longitudinal relations of caffeinated coffee, decaffeinated coffee, and total caffeine intakes with mean blood pressure and incident hypertension in postmenopausal women in the Women's Health Initiative Observational Study.

DESIGN

In a large prospective study, type and amount of coffee and total caffeine intakes were assessed by using self-reported questionnaires. Hypertension status was ascertained by using measured blood pressure and self-reported drug-treated hypertension. The mean intakes of caffeinated coffee, decaffeinated coffee, and caffeine were 2-3 cups/d, 1 cup/d, and 196 mg/d, respectively. Using multivariable linear regression, we examined the associations of baseline intakes of caffeinated coffee, decaffeinated coffee, and caffeine with measured systolic and diastolic blood pressures at annual visit 3 in 29,985 postmenopausal women who were not hypertensive at baseline. We used Cox proportional hazards models to estimate HRs and their 95% CIs for time to incident hypertension.

RESULTS

During 112,935 person-years of follow-up, 5566 cases of incident hypertension were reported. Neither caffeinated coffee nor caffeine intake was associated with mean systolic or diastolic blood pressure, but decaffeinated coffee intake was associated with a small but clinically irrelevant decrease in mean diastolic blood pressure. Decaffeinated coffee intake was not associated with mean systolic blood pressure. Intakes of caffeinated coffee, decaffeinated coffee, and caffeine were not associated with the risk of incident hypertension (P-trend > 0.05 for all).

CONCLUSION

In summary, these findings suggest that caffeinated coffee, decaffeinated coffee, and caffeine are not risk factors for hypertension in postmenopausal women.

Association of daily coffee and tea consumption and metabolic syndrome: results from the Polish arm of the HAPIEE study

Purpose

The aim of this study was to evaluate whether daily consumption of coffee and tea was associated with components and prevalence of metabolic syndrome (MetS) in the Polish arm of the Health, Alcohol and Psychosocial factors In Eastern Europe cohort study.

Methods

A cross-sectional population-based survey including 8,821 adults (51.4 % female) was conducted in Krakow, Poland. Coffee and tea consumption was evaluated using food frequency questionnaires. MetS was defined according to the International Diabetes Federation definition. Linear and logistic regression models were performed to estimate odds ratios and confidence intervals.

Results

Among high coffee and tea consumers (3 or more cups/day), high prevalence of female gender, young age, medium–high educational and occupational level, high total energy intake, and smoking habit were found. High coffee drinkers had lower BMI, waist circumference, systolic and diastolic blood pressure, triglycerides, and higher HDL cholesterol than those drinking less than 1 cup/day. In contrast, high tea consumers had lower BMI, waist circumference, but not diastolic blood pressure, which was higher than low drinkers. After adjusting for potential confounding factors, both higher coffee and tea consumption were negatively associated with MetS (OR 0.75, 95 % CI 0.66, 0.86 and OR 0.79, 95 % CI 0.67, 0.92, respectively). Among specific components of MetS, high coffee consumption was negatively associated with waist circumference, hypertension, and triglycerides, whereas tea consumption with central obesity and fasting plasma glucose in women, but not in men.

Conclusions

Coffee and tea consumption was negatively associated with MetS and some of its components.

Consumption of green coffee reduces blood pressure and body composition by influencing 11β-HSD1 enzyme activity in healthy individuals: a pilot crossover study using green and black coffee

Dietary polyphenols may have a protective role against the development of CVD. Thus, we aimed to investigate the effects of green coffee (GC), rich in chlorogenic acid, and black coffee (BC) on cardiovascular markers. A randomised pilot crossover study was performed on healthy subjects who consumed both coffees for 2 weeks. We measured anthropometry, blood pressure, and arterial elasticity after each intervention and collected urine samples to monitor antioxidant capacity. Free cortisol and cortisone levels were obtained from urine and analysed by specific ELISA methods. Systolic blood pressure (P = 0.018) and arterial elasticity (P = 0.001) were significantly reduced after GC. BMI (P = 0.04 for BC; P = 0.01 for GC) and abdominal fat (P = 0.01 for BC; P = 0.009 for GC) were also significantly reduced with no changes in energy intake. Urinary free cortisol was significantly reduced from 125.6 ± 85.9 nmol/day to 76.0 ± 54.9 nmol/day following GC and increased to 132.1 ± 89.1 nmol/day after BC. Urinary free cortisone increased by 18% following BC and 9% following GC (nonsignificant). Cortisol/cortisone ratio (indicating 11β-HSD1 activity) was reduced after GC (from 3.5 ± 1.9 to 1.7 ± 1.04, P = 0.002). This suggests that GC can play a role in reducing cardiovascular risk factors. Further research including hypertensive and overweight individuals will now be justified to clarify whether GC could have a therapeutic role in CVD.

Caffeine intake improves fructose-induced hypertension and insulin resistance by enhancing central insulin signaling

Recent clinical studies found that fructose intake leads to insulin resistance and hypertension. Fructose consumption promotes protein fructosylation and formation of superoxide. In a previous study, we revealed that inhibition of superoxide production in the nucleus tractus solitarii (NTS) reduces blood pressure. Caffeine displays significant antioxidant ability in protecting membranes against oxidative damage and can lower the risk of insulin resistance. However, the mechanism through which caffeine improves fructose-induced insulin resistance is unclear. The aim of this study was to investigate whether caffeine consumption can abolish superoxide generation to enhance insulin signaling in the NTS, thereby reducing blood pressure in rats with fructose-induced hypertension. Treatment with caffeine for 4 weeks decreased blood pressure, serum fasting glucose, insulin, homeostatic model assessment-insulin resistance, and triglyceride levels and increased the serum direct high-density lipoprotein level in fructose-fed rats but not in control rats. Caffeine treatment resulted in the recovery of fructose-induced decrease in nitric oxide production in the NTS. Immunoblotting and immunofluorescence analyses further showed that caffeine reduced the fructose-induced phosphorylation of insulin receptor substrate 1 (IRS1(S307)) and reversed Akt(S473) and neuronal nitric oxide synthase phosphorylation. Similarly, caffeine was able to improve insulin sensitivity and decrease insulin levels in the NTS evoked by fructose. Caffeine intake also reduced the production of superoxide and expression of receptor of advanced glycation end product in the NTS. These results suggest that caffeine may enhance insulin receptor substrate 1-phosphatidylinositol 3-kinase-Akt-neuronal nitric oxide synthase signaling to decrease blood pressure by abolishing superoxide production in the NTS.

[Caffeine in analgesics--myth or medicine?]

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

Caffeine and blood pressure response: sex, age, and hormonal status

PURPOSE

The pressor effect of caffeine has been established in young men and premenopausal women. The effect of caffeine on blood pressure (BP) remains unknown in postmenopausal women and in relation to hormone replacement therapy (HRT) use.

MATERIALS AND METHODS

In a randomized, 2-week cross-over design, we studied 165 healthy men and women in 6 groups: men and premenopausal women (35-49 yrs) vs. men and postmenopausal women (50-64 yrs), with postmenopausal women divided into those taking no hormone replacements (HR), estrogen alone, or estrogen and progesterone. Testing during one week of the study involved 6 days of caffeine maintenance at home (80 mg, 3x/day) followed by testing of responses to a challenge dose of caffeine (250 mg) in the laboratory. The other week involved ingesting placebos on maintenance and lab days. Resting BP responses to caffeine were measured at baseline and at 45 to 60 min following caffeine vs placebo ingestion, using automated monitors.

RESULTS

Ingestion of caffeine resulted in a significant increase in systolic BP in all 6 groups (4 +/- .6, p < 0.01). Diastolic BP significantly increased in response to caffeine in all (3 +/- .4, p < 0.04) but the group of older men (2 +/- 1.0, p = 0.1). The observed pressor responses to caffeine did not vary by age.

CONCLUSIONS

Caffeine resulted in an increase in BP in healthy, normotensive, young and older men and women. This finding warrants the consideration of caffeine in the lifestyle interventions recommended for BP control across the age span.