Coffee is the most widespread drink in the world. It has also been one of the most studied foods in the medical literature. We discussed previously a study showing it may reduce your chances of getting some cancers. A recent study also shows a reduced chance of dying of heart disease, respiratory disease, stroke, diabetes, and a reduced chance of just dying. Because it is one of the foods high in potassium, one question about coffee is whether these favorable effects on health come from the potassium, or from one or more of the other thousand or so bioactive compounds in coffee.
Coffee is technically not one of the high potassium foods because it does not provide 200 mg of potassium in a single serving. But it does provide 115 to 130 mg in a cup. If you drink several cups a day, it can be a source of a great deal of potassium. Six cups would provide between 690 to 780 mg of potassium in a day.
Coffee And Health
There has been a major study (1) showing that as coffee consumption increased, mortality decreased. There were fewer early deaths from heart disease, respiratory disease, strokes, and diabetes in coffee drinkers. The study was done over 14 years. It included 600,000 participants over the age of 50, all from the United States. The researchers corrected for a number of possible confounders, such as gender, smoking, exercise, and diet.
As with the study we discussed previously about the reduced risk of cancer in coffee drinkers, the researchers found that the more coffee people drank, the lower the mortality. In contrast to that study, they did not find a lowering of mortality from cancer, though. There was no effect one way or the other.
Because coffee is not thought of as part of a healthy lifestyle in the U.S., coffee drinkers in the study were more likely to smoke, consume more than 3 alcoholic drinks per day, and eat more red meat. They also were less educated, less likely to exercise, and ate less fruits and vegetables.
Despite this, the more coffee the participants drank, the lower their mortality overall. And there were fewer deaths from heart disease, respiratory disease, strokes, and diabetes. Although the study did not look at what it is about coffee that contributes to this effect, they speculated that it could be related to the many bioactive compounds in coffee. They did not comment at all on coffee's potassium content.
Coffee And Atherosclerosis
Another study (2) studied over 5000 young people who were age 18 to 30 at the start of the study. The researchers followed them for 20 years. They examined the thickness of their carotid arteries in the neck. This artery is a common source of stroke when it becomes thickened or calcified. The arteries of the coffee drinkers did not show any increase in thickness or calcification over the 20 years.
The researchers also studied the effect on the coronary (heart) arteries. They found no effect from drinking coffee. And they examined the effect of tea consumption. Tea consumption had no effect on the carotid arteries, but actually provided protection of the coronary arteries.
These are just 2 of many thousands of studies on the health effects of coffee. They were chosen because they represent a growing body of evidence that coffee is not harmful. It actually is good for you, contributing to improved health in many ways. It does not contribute to heart disease, arterial disease, strokes, diabetes or cancer, and actually may help prevent these diseases.
Some Downside To Coffee
Of course, coffee has some acute effects that may be harmful to some types of people. It increases blood pressure slightly for a short period after drinking it. And it can cause irregular heartbeats in susceptible people. Those people need to be careful with their coffee consumption.
Also there are those who are kept awake at night if they drink it late in the day. Those who have this susceptibility would need to get their coffee early in the day.
Because of the acute effects, it is probably best to get coffee throughout the day in small divided doses. This minimizes the acute effects, and still allows getting a good amount of coffee.
The possible components of coffee that contribute to health remain speculative. Much like red wine, which has many potential functional components that may contribute to it as a functional food, coffee has many hundreds of bioactive compounds. The most popular bioactive compounds being studied at present are the flavonoids and polyphenols. These compounds are only useful for forming hypotheses for studies. But no conclusions can be drawn at this time about which are contributors to better health.
Yet one thing has become clear over the many years and many studies done on coffee. Coffee does not cause the harm that so many alarmists have proclaimed over the years. The more the better, at least up to 6 cups per day for most of us. So drink up.
1. Association of Coffee Drinking with Total and Cause-Specific Mortality, Neal D. Freedman, Ph.D., Yikyung Park, Sc.D., Christian C. Abnet, Ph.D., Albert R. Hollenbeck, Ph.D., and Rashmi Sinha, Ph.D., N Engl J Med 2012; 366:1891-1904May 17, 2012DOI: 10.1056/NEJMoa1112010
2. Coffee, decaffeinated coffee, caffeine, and tea consumption in young adulthood and atherosclerosis later in life: the CARDIA study. Reis JP, Loria CM, Steffen LM, Zhou X, van Horn L, Siscovick DS, Jacobs DR Jr, Carr JJ., Arterioscler Thromb Vasc Biol. 2010 Oct;30(10):2059-66. doi: 10.1161/ATVBAHA.110.208280. Epub 2010 Jul 8.