Caffeine and Incident Hypertension in Women

Abstract

1 found an inverse U-shaped relationship between habitual caffeine consumption and incident hypertension in a prospective cohort study of US women followed up for 12 years in the Nurses' Health Studies. However, when examining classes of caffeinated beverages, coffee consumption was not linked to an increased risk of hypertension. In contrast, cola beverage consumption was associated with an increased risk, independent of whether it was sugared or diet cola. The authors speculated that the substance responsible for the increased risk of hypertension in the cola drinks is a compound other than caffeine.Caffeine may still be the cause of the hypertension. Coffee has higher caffeine content than cola, and the average US diet receives 71% of its caffeine intake from coffee, 16% from cola, and 12% from tea.2 However, coffee contains antioxidants that consist of flavonoids, phenols, and melanoidins (from the roasting process), while cola is almost devoid of antioxidants as measured by 3 antioxidant assays. 3A coffee bean extract, chlorogenic acid (a major antioxidant ingredient of coffee), and a chlorogenic acid metabolite all decreased blood pressure in spontaneously hypertensive rats.4 Filtered coffee (3-4 cups/day) given to habitual alcohol drinkers with elevated blood pressure produced a decline in both systolic and diastolic blood pressure. When coffee was removed from the diet the blood pressure increased in the participants. 5 The antioxidant components of coffee thus appear to be hypotensive agents.Winkelmayer et al found a positive trend for tea drinking and hypertension. Although tea contains flavonoid and phenolic antioxidants, it has little of the chlorogenic acid found in coffee, suggesting that the caffeine in tea is responsible for the hypertensive effect.Thus, the antioxidants in coffee may blunt the blood pressure-elevation effect of caffeine. The colas, which contain caffeine but no antioxidants, may cause the increase in risk of hypertension seen in this study. Further, it is possible that regular consumption of decaffeinated coffee, which contains similar levels of antioxidants as caffeinated coffee, 3 might decrease blood pressure in normotensive and hypertensive individuals. To the Editor: In their study of habitual caffeine intake and the risk of hypertension, Dr Winkelmayer and colleagues 1 analyzed data from a large population-based cohort study in US nurses. Total caffeine intake was associated with risk of hypertension in this study, but no relationship with consumption of caffeinated coffee was observed. Cola and other caffeinated soft drinks, however, appeared to increase blood pressure.Findings from this study are compatible with a recent meta-analysis that we conducted, in which we combined data from randomized controlled trials to examine the effect of both coffee and caffeine on blood pressure.2 When caffeine trials (n=7) and coffee trials (n=18) were analyzed separately, blood pressure elevations appeared to be 4 times greater for caffeine given as tablets (4.2 mm Hg systolic and 2.4...

Time for tea: mood, blood pressure and cognitive performance effects of caffeine and theanine administered alone and together

“…Certain compounds such as cafestol (the presence of which is affected by brewing method) may increase risk, but chlorogenic acid and other polyphenols are thought to have beneficial effects (e.g. Hamer 2006;Vinson 2006;Cornelis and El-Sohemy 2005). Activity of one or more of these compounds may additionally explain why coffee reduces risk of type 2 diabetes (van Dam and Hu 2005), which is itself a risk factor for cardiovascular disease (Yamagishi et al 2006).…”

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

“…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).…”