You might be reading this article while enjoying a nice, hot cup of your favorite morning brew. The aromas and flavors of coffee are rich and delicious, and some folks just can’t get going without it or the boost its caffeine provides.
Like so many of our favorite foods and beverages, coffee has been the subject of conflicting health information through the decades. Back in the early 1990s, the World Health Organization even listed it as a possible carcinogen. New research by 2016 showed coffee consumption was not associated with increased cancer risk, and the picture became even murkier when other research showed coffee consumption could actually cut the risk of certain cancers.
What are we supposed to believe? Is there a definitive answer as to whether coffee helps or harms our health?
Some of the newer studies on coffee have been larger and, therefore, are felt to be more accurate and relevant, though there are no large, randomized trials on coffee drinking, which are the best type of trials.
“The trials that have been done are observational, which look back and see how coffee drinking was related to a population of patients and whether they developed heart artery disease such as heart attacks or stroke,” explains Dr. Amish Mehta, cardiologist and Director of Noninvasive Cardiology at Allegheny Health Networks’ Jefferson Hospital. “In general, the more recent larger trials seem to indicate that coffee does no cardiovascular harm and may in fact have benefits to the heart.”
Coffee is a source of caffeine, vitamin B2 (riboflavin), magnesium and plant chemicals including polyphenols. One eight-ounce cup of brewed coffee contains about 95 mg of caffeine. A moderate amount of coffee is generally defined as three to five cups a day, or an average of 400 mg of caffeine.
To make things even more confusing, health benefits might not just depend on whether you drink coffee but rather on what kind of coffee and amount you drink. One of the studies from Europe found that ground and instant coffees, but not decaffeinated, were also found to reduce risk of irregular heartbeat called arrhythmia. Four to five daily cups of ground coffee and two to three cups of instant lowered arrhythmias by 17% and 12%, respectively. The question remains whether caffeine benefits the heart or whether it’s the other components in coffee that help.
“Most scientists seem to feel that the benefits from drinking coffee are not necessarily related to the caffeine but some of the other biologically active compounds that are found in coffee,” says Mehta. “It seems that both caffeinated as well as decaffeinated coffee have benefits, therefore it is not felt to be the caffeine.”
How does coffee help? Some reported benefits include decreased inflammation, improvement of how insulin works in the body, boosted metabolism, antioxidants and potentially blocking receptors that may cause irregular heart rhythms. Those are the pros, but there are cons, too.
“We do know that caffeine can increase blood pressure, so we recommend to patients that they not check their blood pressure for at least 30 minutes after drinking coffee,” Mehta said. “Patients with severe high blood pressure, potentially a blood pressure consistently running higher than 160/100, should consider avoiding coffee until their blood pressure is under better control. Coffee is a stimulant, but drinking in moderation of two to six cups per day is safe.”
When it comes to increasing or decreasing cancer risk, the answer is still somewhat unclear. Research shows there is some evidence that coffee can lower prostate cancer, liver cancer, endometrial cancer and some oral and throat cancers. “But in some of those studies, individuals had to drink four to six cups of coffee a day, which is a significant amount,” Mehta said. “If people add cream and sugar, this can contribute to excess calories and weight gain, which can actually cause cancers. Therefore, the relationship of coffee to cancer is somewhat unclear, and may be neutral.”
He recommends other actions to lower cancer risk, such as avoiding smoking, eating a healthy diet high in fruits and vegetables, and being physically active.
In the end, Mehta says these are the takeaways:
- When it comes to heart disease, coffee may have some benefit or no benefit. It does not seem that coffee is harmful.
- Individuals should be careful about trying to minimize the amount of cream and sugar they add to coffee, as they contribute extra calories.
- Patients should not check their blood pressure for 30 minutes after drinking coffee. If an individual has severely elevated blood pressure, they should avoid coffee until their blood pressure is under good control.
- Coffee is a stimulant and can interfere with sleep.
Ground and instant coffee, caffeinated and decaf: All may provide potential cardiac benefit, as the benefits seem to come from chemicals in the coffee itself and not related to the caffeine.
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