Caffeine has long been known to elevate blood pressure (BP). A well-designed study examined the impact of 250 mg of caffeine in subjects who had consumed no coffee in the previous 3 weeks. This study found caffeine increased BP by an average of 14/10 mmHg an hour after consumption. A clinical trial of patients with hypertension who stopped drinking coffee did find a significant drop in BP, at least in the short-term.1 2

Coffee can raise BP by narrowing blood vessels. Coffee, including decaffeinated, has been shown to raise homocysteine (Hcy) levels in the blood.3 Increased levels of Hcy and LDL damage endothelial cells and reduce their nitric oxide (NO) activity. NO is the major vasodilating agent in blood vessels.There is no doubt that coffee and caffeine can elevate BP acutely. The more important consideration is whether or not they contribute to the gradual rise in BP seen with age in all modern societies. A study that followed 1017 former medical students for an average of 33 years found a modest increase in the incidence of hypertension (HTN) over time in the coffee drinkers compared to those who did not drink coffee. Nevertheless, BP still rose markedly with age even in those who never drank coffee. The authors of this study conclude, “Over many years of follow-up, coffee drinking is associated with small increases in blood pressure, but this appears to play a small role in the development of hypertension.”4The impact of caffeine and coffee on BP is largely short-lived, and there is no compelling evidence to suggest it plays a major role in the inexorable rise in BP seen with age in all modern human populations. Nevertheless, it seems prudent to advise HTN or high BP patients to cut back or even stop drinking coffee. At least in the short-term, this will help lower BP and should reduce other cardiovascular disease risk factors like LDL and Hcy.The bottom line: There is no doubt that coffee and caffeine cause a transient rise in BP, but there is little evidence to suggest that those who consume a lot of coffee and other sources of caffeine are at a much greater risk for developing HTN.References:1. Am L Cardiol 1994;73:780-42. N Engl J Med 1978;298:181-63. Am J Clin Nutr 2001;74:302-74. Arch Intern Med 2002;162:657-62For more information on the treatment and prevention of HTN, see the new CPE course on Salt Toxicity found in the CPE section at www.foodandhealth.com.