Drinking more than three cups of coffee a day may place you at no greater risk of high blood pressure than the occasional cup, according to a recent analysis of six observational studies. The studies showed that people who drink one to three cups of coffee a day have slightly elevated blood pressure, but those who drink more than three cups a day do not.
How might drinking more coffee be less hazardous? One possibility: Coffee is high in potassium, which lowers blood pressureso the more you drink, the more protection you may be afforded from coffee's hypertensive effect.
Source: American J. of Clinical Nutrition, vol. 93, p. 1212; Prepared by the Editors of The Johns Hopkins Medical Letter: Health After 50