Let’s be honest, you probably don’t feel like yourself until you have your morning coffee. And you’re not alone: about 83 percent of adults drink coffee in the U.S. This is roughly equivalent to 120 million daily coffee drinkers (1).
Even though it’s a major staple of morning routines worldwide, the medical community has been skeptical concerning the safety of this drink.
Up until May 2016, it was believed that coffee could cause cancer. The World Health Organization (WHO) even went so far as to describe the beverage as “possibly carcinogenic,” in 1991, linking it to bladder cancer. The organization has since debunked this claim (2).
In a recent WHO report, 23 scientists from ten countries worked in collaboration with the International Agency for Research on Cancer (IARC) to analyze 1,000 studies on the relationship between coffee and cancer. They concluded that instead of being carcinogenic, coffee had the ability to protect against multiple kinds of cancer (3,4).
How Coffee Fights Cancer
In 2011, the scientific journal BMC Cancer published the results of meta-analyses and meta-regressions of 59 studies on coffee, including 40 independent cohorts (5).
They found that the studies suggested that regular coffee consumption reduced the risk of bladder, breast, buccal and pharyngeal, colorectal, endometrial, esophageal, hepatocellular, leukemic, pancreatic, and prostate cancers.
This is due to two specific diterpenes in coffee, cafestol, and kahweal. The compounds are believed to boost the activity of other anticarcinogenic substances.
Another powerful compound, caffeic acid, influences the cell cycle of cancer cells to reduce the size of tumors. It also modulates stress and inflammatory response.
What Caused The Confusion
It’s worth mentioning that the main reason drinking coffee was linked to cancer in the first place had to do with a closely related habit: smoking. This may have lead scientists to link the healthier of the two habits with the devastating disease.
“When these studies originally got started, back in the ’50s and the ’60s, it would be difficult to find an adult in this country that didn’t start their day off without having a cigarette and a cup of coffee,” said Dr. Roy A. Jensen, the director of the University of Kansas Cancer Center. “When so many people are engaging in two behaviors that are tightly linked, it becomes very difficult to disassociate those.”
Celebrate with a Cup (But Don’t Have too Much!)
Other studies have found that regular coffee consumption can lead to lower rates of heart disease, Type II diabetes, neurological disorders (including Alzheimer’s disease), liver disease, and liver damage (6).
“What I tell patients is, if you like coffee, go ahead and drink as much as you want and can,” says Dr. Peter Martin, director of the Institute for Coffee Studies at Vanderbilt University.
The American Medical Association agrees that “moderate tea or coffee drinking likely has no negative effect on health, as long as you live an otherwise healthy lifestyle.” It is possible to have too much of a good thing, so make sure not to go beyond the 3-5 cups recommended by the U.S. government’s dietary guidelines.
Although coffee has been given the clear, there are some strings attached.
Coffee Causes Cancer At This Temperature
The WHO report stated that drinking coffee at temperatures beverages at or above 149 degrees Fahrenheit (65 degrees Celsius) probably causes esophageal cancer. The agency has since classified hot beverages as “probably carcinogenic to humans” (7).
Coffee or other hot beverages at or above the cutoff temperature can burn the esophagus, and it’s that scalding that seems to trigger cancer, according to the report.
This link between hot drinks and cancer works in a similar way to the link between alcohol consumption and esophageal cancer, the eighth-most-common form of cancer worldwide, she said. So next time you brew a cup coffee, let is cool a little before taking a sip.