In an unexpected reversal, The World Health Organization (WHO) has now concluded that coffee may not cause cancer after all. The International Agency for Research on Cancer (IARC) report published in The Lancet Oncology, had this to say:
“After thoroughly reviewing more than 1,000 studies in humans and animals, the Working Group found that there was inadequate evidence for the carcinogenicity of coffee drinking overall.
Many epidemiological studies showed that coffee drinking had no carcinogenic effects for cancers of the pancreas, female breast and prostate, and reduced risks were seen for cancers of the liver and uterine endometrium.
For more than 20 other cancers, the evidence was inconclusive.”
However, the IARC report notes that hot coffee or tea can pose a health risk if it exceeds 149° and may be a cause of esophageal cancer.
Interestingly, the bulk of the IARC report dealt with the threat of drinking scalding hot coffee as opposed to the apparently non-existent hazards of the coffee itself.
“Last year, a panel of scientists that shaped the federal government’s 2015 dietary guidelines said there was ‘strong evidence’ that three to five cups of coffee daily was not harmful, and that ‘moderate’ consumption might reduce chronic disease.
Another group, the World Cancer Research Fund International, reported that coffee protects against multiple types of cancer. And several systematic reviews of studies involving millions of people have found that regular coffee drinkers live longer than others.
The evidence is fairly convincing that coffee may not only lower your cancer risk, but also your risk of heart disease, type 2 diabetes and neurological disorders.
In 1991 coffee was classified as a “possible carcinogen” linked to bladder cancer. Early reports on coffee had compared its hazards with those of lead and diesel fuel.
Those previous studies hadn’t taken into account that many of the coffee drinkers that took part in these initial studies were also heavy smokers, according to Dana Loomis, Ph.D.,
first author of the report and deputy head of the WHO program focused on cancer-causing substance classifications. In addition, more up-to-date studies have become available.
Since then, 40 studies found either zero connection between coffee consumption and cancer risk or found it actually produced a slightly protective effect. Some of the studies under most scrutiny were those associating coffee consumption with decreasing uterine and liver cancer risks.
One of the most telling was a report that coffee drinkers exhibit a 15 percent decrease in liver cancer risk for every cup of coffee ingested per day.
A Harvard T.H. Chan School of Public Health analysis in 2012 reported that drinking coffee was linked to a decreased endometrial cancer risk.
Another study concluded that drinking at least five cups of coffee a day prevents some brain cancers by as much as 40 percent.
In 2015, the U.S. Department of Agriculture (USDA) submitted new dietary guidelines concluding that three to five cups of coffee a day — 400 milligrams of caffeine — was linked to a lowered risk of Parkinson’s disease.
With all this information about coffee, the Mayo Clinic noted on its website that in deciding whether coffee is a positive or negative, it’s possible that the health benefits outweigh the risks. “What the evidence shows overall is that coffee drinking is associated with either reduced risk of several cancers or certainly no clear increase in other cancers … There’s a strong signal that this is probably not something that we need to be worrying about.”
Dark Roast or Light?
The roasting process has a significant effect on the caffeine content of coffee. For those looking for a higher levels of caffeine by drinking a darker roast, you may be surprised that the dark roast will not deliver the jolt you are looking for. It may be counter-intuitive, but the added roasting time to make it darker actually breaks down the caffeine molecules.
Another byproduct of the roasting process is the chemical acrylamide, which is listed as a carcinogen under Proposition 65. One may think to lower the acrylamide content in coffee this would necessitate choosing a lighter roast, but strangely enough, at least one study found that the highest amount of acrylamide appears earlier in the roasting process rather than later, after which the acrylamide level begins to degrade. Another benefit of dark roasts is that they generate more of the chemical N-methylpyridinium than the lighter roasted coffee beans, which helps keep your stomach from producing excess acid. In addition Italian or French dark-roasted coffee or the types used for espresso or Turkish coffee contain more antioxidants such as vitamin E, and neuro-protective agents and protein-building glutathione than lighter roasts.