Coffee is a complex beverage full of different chemicals and compounds. Although nearly everyone knows about the caffeine in regular coffee, most people do not think of phenolics, antioxidants or the more than 1,000 aroma compounds contained in coffee. It is this chemical complexity that can result in coffee’s effects on blood pressure.
Caffeine and Blood Pressure
Caffeine is a well-known stimulant. According to Dr. Sheldon Sheps of the Mayo Clinic, caffeine from any source, including coffee, can cause an increase in blood pressure. The mechanism of this effect is unknown. It could be related to caffeine’s effect on a hormone that helps to keep your arteries open, or caffeine could increase the production of adrenalin, which raises blood pressure. A study in the April 2011 “Food and Function” reports that caffeine given to habitual coffee and tea drinkers resulted in increased blood pressure even at low doses.
Coffee, Stress and Blood Pressure
Coffee was compared to caffeine in a study reported in the September 2005 issue of “Hypertension.” Healthy volunteers, some of whom regularly consumed coffee and some who normally abstained, were subjected to mental stress and given a triple espresso, intravenous caffeine or a placebo. Those who normally did not drink coffee had an increased blood pressure when subjected to mental stress and given a triple espresso, but did not react to the caffeine. The researchers concluded that compounds in the coffee other than caffeine were responsible for the increase in blood pressure.
Four Cups a Day
A published in the 2008 issue of “Vascular Health and Risk Management,” noted that more than four cups of coffee a day provided a protective effect against hypertension–high blood pressure–in women. Drinking more than five cups of coffee a day caused a small increase in blood pressure when compared to coffee abstinence or decaffeinated coffee. The author noted that many of the substances in coffee, such as phenols and potassium, might actually be beneficial for the cardiovascular system.
One to Three Cups a Day
An extensive review of studies on coffee and high blood pressure reported in the June 2011 “American Journal of Clinical Nutrition” found that people who drank less than one cup of coffee per day did not have a risk of hypertension, but when consumption increased to one to three cups per day, there was a slightly increased risk of developing hypertension.
Considerations
Moderate coffee consumption probably won’t affect your blood pressure significantly. But if you have hypertension and your blood pressure is difficult to control, you might want to consider going without caffeine to see it there is an improvement. If you have questions or concerns, consult a health care professional.
References
- “Vascular Health and Risk Management”; Habitual Coffee Consumption and Blood Pressure: An Epidemiological Perspective; J.M. Geleijnse; 2008
- “American Journal of Clinical Nutrition”; Habitual Coffee Consumption and Risk of Hypertension: A Systematic Review and Meta-Analysis of Prospective Observational Studies; Z. Zhang, et al.; June 2011
- MayoClinic.com; How Does Caffeine Affect Blood Pressure?; Sheldon G. Sheps, M.D.; November 2009
- Royal Society of Chemistry; Chemistry in Every Cup; Emma Davies; May 2011
- “Food and Function”; Habitual Coffee and Tea Drinkers Experienced Increases in Blood Pressure After Consuming Low to Moderate Doses of Caffeine; These Increases Were Larger Upright Than in The Supine Posture; M.K. McMullen, et al.; April 2008
- “Hypertension”; Coffee Blunts Mental Stress-Induced Blood Pressure Increase in Habitual But Not in Nonhabitual Coffee Drinkers; I. Sudano, et al.; September 2005
