Busting myths: Can coffee cause, cure or prevent cancer?

Can coffee cause cancer or prevent it? Learn some of the myths and realities when it comes to coffee and cancer.
For many, the only way to start the day is with a hot, steaming cup of coffee. Whether you call it java, joe or jitter juice, or take it black or with cream and sugar, Americans are drinking more coffee than ever. A National Coffee Association survey released in March showed 64 percent of adult Americans have at least one cup of coffee per day. A cup of home-brewed joe may have at least 95 mg of caffeine, enough to jumpstart the day for most. For those who may seek a more potent morning jolt, a 20-ounce take-out from a popular coffee house franchise can have upwards of 475 mg of caffeine, according to the Center for Science in the Public Interest.

Coffee and cancer have had a rocky relationship over the years. Coffee was once recklessly touted as a cancer treatment and later declared a carcinogen. Today, new studies indicate it may help prevent certain types of cancer. And recently, a California judge stirred controversy by ruling that a health warning should be attached to coffee sold in that state. So, what are the myths and realities when it comes to coffee and cancer?

Can coffee increase the risk of cancer?

“There is no clear evidence linking coffee consumption and increased risk of cancer,” says Anthony Perre, MD, Chief of the Division of  Outpatient Medicine at Cancer Treatment Centers of America® and an Internist at our Philadelphia hospital. In fact, the World Health Organization (WHO) removed coffee from its list of carcinogens in 2016. WHO added coffee to its list of risk factors more than 25 years ago, but reversed course after more recent studies found no evidence that coffee increased cancer risk. “A study published in 2017 showed that drinking two cups of coffee a day may lower the risk for several cancer types, including breast cancer, colorectal cancer, liver cancer and head and neck cancers,” Dr. Perre says. “There are probably a number of factors that may contribute to the reduced risk.” The bottom line is there’s no overwhelming evidence that coffee can cause or help prevent cancer.

Why is coffee considered a carcinogen in California?

While there is no evidence coffee itself raises cancer risk, a substance formed when coffee is processed may. “There has been some concern about acrylamide, which is formed when coffee beans are roasted,” Dr. Perre says. In a court decision that stirred much debate, a California judge ruled that coffee sold in the state required a cancer warning because of the presence of acrylamide. The substance is listed among 900 chemicals that require warning labels under the state’s Safe Drinking Water and Toxic Enforcement Act, known as Prop 65. Acrylamide is a chemical used in the production of some paper and plastic products. It also forms in some starchy foods cooked at high temperatures. According to the American Cancer Society (ACS), “most of the studies done so far have not found an increased risk of cancer in humans.” But the ACS suggests more studies are needed. “For now, it is suggested that we may wish to reduce our consumption of other foods high in acrylamide—like French fries, potato chips, crackers, bread, cookies and breakfast cereals,” Dr. Perre says.

Can drinking hot coffee or other beverages increase cancer risk?

In 2016, WHO classified hot beverages as a probable carcinogen after the International Agency for Research on Cancer concluded that very hot beverages can cause cell damage and inflammation that may lead to cancer. Experts recommend not drinking hot beverages above 149 degrees Fahrenheit, or 65 degrees Celsius.

Are coffee enemas a viable treatment for colon cancer?

Information abounds on the alleged cancer-treating benefits of coffee enemas. The theory behind this unusual treatment is that coffee delivered directly into the colon causes rapid caffeine absorption that jumpstarts detoxification. The treatment was part of The Gerson Therapy, named for Max Gerson, MD, who promoted detoxification through enemas, juices and organic fruits and vegetables. In 1947, the National Cancer Institute called Gerson’s practice into question and found that cancer had progressed in all his patients. The U.S. Food and Drug Administration has not approved The Gerson Therapy to treat cancer or other diseases, and there is no evidence coffee enemas can successfully treat cancer. On the other hand, coffee enemas do come with some risks, including internal burns, colitis and infections.

Wissam Jaber, MD, an Interventional Pulmonologist at our Phoenix hospital, suggests patients check with their oncologists or other members of their care team before trying new or unconventional cancer treatments. Also, he said, those treatments should not act as alternative to their normal care regimen. “I tell my patients, if they want to try new things, let us know about it,” he says. “If we think it’s safe, they are perfectly fine to try them as long as they don't use it as a substitute for proven scientific treatments. If you get approval from your doctor to do something new or different, do it. But don't skip your chemotherapy.”