Coffee and health: explaining conflicting results in hypertension

Abstract

It is well established that dietary intake and other lifestyle factors play an important role in hypertension. 1 Available evidence suggests hypertensive patients should follow a weight-reducing diet, restrict alcohol and salt intake, reduce smoking and incorporate regular physical activity into their lifestyle. Another area of much interest relates to the impact of coffee consumption on blood pressure (BP), which was first debated nearly 30 years ago. 2 Coffee is one of the most widely consumed nonalcoholic beverages in Western society, although research pertaining to its effects on health, and particularly hypertension, remains equivocal.Previously reviewed evidence from a variety of cross-sectional and longitudinal epidemiologic studies of the effects of coffee consumption on BP appear to be inconsistent, demonstrating no effects, positive relations and inverse relations. 3 There are only two prospective cohort studies to date that have examined the influence of coffee intake on the risk of hypertension development, which present conflicting findings. Winkelmayer et al. 4 demonstrated no relationship between coffee intake and incident hypertension in 155 594 US women followed up over 12 years. However, in a cohort of 1017 men followed up over 33 years, coffee drinkers had a greater incidence of hypertension in unadjusted analyses and consumption of one cup of coffee significantly raised systolic and diastolic BP by 0.19 and 0.27 mm Hg, respectively, in adjusted models. 5 The nonsignificant association with incident hypertension after multivariate adjustment may therefore suggest that coffee drinking plays only a minor role. However, a confounding problem with such prospective studies is that individuals with heightened BP may be advised to moderate their coffee intake, thus impacting upon the findings.Recent meta-analyses that have examined the influence of coffee and caffeine intake on BP from randomized controlled trials (RCTs) also present conflicting findings. In an analysis of 11 trials, the BP effects of coffee were estimated as 2.4 and 1.2 mm Hg for systolic and diastolic BP, respectively, compared with the non-coffee groups, 6 which contrasts with smaller effects of 1.22 and 0.49 mm Hg in a larger meta-analysis of 16 studies. 7 The mean treatment duration was similar in both analyses, although mean caffeine dosage was higher in the earlier study 6 (see Table 1), which may explain the discrepancy in effect size. Hypertensive status, genetic vulnerability to hypertension and interactions with smoking and mental stress may also be important. A small amount of evidence suggests that pressor responses to coffee are exaggerated in hypertensives and additive in combination with smoking or mental stress, 3 although in stratified analyses, baseline BP was not associated with effects of coffee on BP in RCTs. 7 Also a recent finding demonstrated that acute administration of coffee resulted in blunted BP responses to mental stress among habitual coffee consumers but was enhanced among non-drinkers. 8 These effect...

Consumption of a boiled Greek type of coffee is associated with improved endothelial function: The Ikaria Study

“…21,22 At last, coffee consumption not only exhibits inherent antioxidant properties, but also activates the endogenous antioxidant defense system by increasing plasma levels of glutathione. 21,22,51 We note the discrepancy between studies concerning the association of coffee consumption and cardiovascular health. These differences can be attributed to the differences in study design (acute versus chronic coffee intake), in study population (healthy subjects, subjects suffering from arterial hypertension, diabetes mellitus or acute cardiovascular events) and to differences in studied endpoints or surrogate markers of cardiovascular disease.…”

“…49,50 Moreover, other micronutrients, including flavonoids, magnesium, potassium, niacin, and vitamin E, contribute to the observed health effects of coffee consumption, mainly because of their antioxidant properties. 51 Concerning boiled Greek coffee, this seems to offer further anti-inflammatory and antioxidant benefits as it contains 0.3-6.7 mg/100 ml cafestol and 0.1-7.1 mg/100 ml kahweol, in contrast with filtered coffee which contains 0-0.1 mg/100 ml of these diterpenes. 21,22 At last, coffee consumption not only exhibits inherent antioxidant properties, but also activates the endogenous antioxidant defense system by increasing plasma levels of glutathione.…”

El Café Y Sus Efectos en La Salud Cardiovascular Y en La Salud Materna

“…Estructura química de cafeín y adenosina que contienen cafeína, sí producen hipertensión (22). En base a esta información, los investigadores concluyen que los antioxidantes contenidos en el café y que no contienen las bebidas energizantes, contrarrestan el posible efecto hipertensor observado pata la cafeína (23).…”

Benefícios do café na saúde: mito ou realidade?

“…De facto, verificou-se uma melhoria da função endotelial e atenuação da hipertrofia vascular e da hipertensão em ratos espontaneamente hipertensos, após administração de ácido clorogénico durante 8 semanas. 201,206 Os estudos publicados não permitem confirmar efectivamente se o consumo de café está ou não associado à hipertensão. No entanto, recomenda-se moderação no consumo em indivíduos hipertensos, fumadores e/ou sujeitos a situações de stress, uma vez que existe um consenso geral de que serão grupos mais susceptíveis ao efeito vasopressor da cafeína.…”