Researchers using data for nearly 500,000 men and women participating in the NIH-AARP Diet and Health Study have purportedly found that coffee consumption is “inversely associated with colon cancer, particularly proximal tumors.” Rashmi Sinha, “Caffeinated and decaffeinated coffee and tea intakes and risks of colorectal cancer in a large prospective study,” American Journal of Clinical Nutrition, June 13, 2012. Ninety percent of the cohort drank coffee, and 16 percent consumed more than four cups per day. “Compared with nondrinkers, heavy coffee drinkers (≥6cups/d) were more likely to be men, current smokers, and physically inactive and consumed more red meat and alcohol but less fruit and vegetables.” Heavy coffee drinkers also apparently consumed predominantly caffeinated coffee.  

According to the researchers, “there was an inverse association between individuals who drank 4-5 cups coffee/d compared with nondrinkers with colon cancer (HR: 0.85; 95%, CI: 0.75, 0.96), and the association was even stronger for subjects who drank ≥6 cups coffee/d (HR: 0.74; 95% CI: 0.61, 0.89).” Those who predominantly drank decaffeinated coffee allegedly had a decreased risk of both colon and rectal cancers, while no associations were found for those who drank tea. The cohort was predominantly non-Hispanic white, college educated and may have had “a healthier lifestyle than that of similarly aged adults in the US population.” Other acknowledged limitations to the researchers’ conclusions included smoking, red-meat consumption, self-reporting, and a lack of information about preparation methods. The authors call for additional investigations into these associations.