Coffee reduces risk of colon cancer by 26% (2016)
- 04/04/2016 - Regular coffee consumption reduces the risk of colorectal cancer, according to results of a study published in Cancer Epidemiology, Biomarkers & Prevention and substantiated by the research of the USC Norris Comprehensive Cancer Center.
Coffee has been proposed as a protective agent against colorectal cancer because several of its components affect the physiology of the colon. These compounds include caffeine, melanoidins, diterpenes, and polyphenols. Protection may arise from changes to the microbiome, antioxidant effects, antimutagenic effects, reduction of bile acid secretion, and improved bowel functions such as motility and capacity.
To substantiate widespread claims of the protective effect of coffee, Stephanie L. Schmit, PhD, MPH, from the USC Norris Comprehensive Cancer Center, University of Southern California, Los Angeles, and colleagues administered a validated, semiquantitative food frequency questionnaire to 5145 cases and 4097 controls from the Molecular Epidemiology of Colorectal Cancer (MECC) study, a population-based investigation in northern Israel.
The researchers considered coffee type (caffeinated or decaffeinated, boiled black coffee, black espresso, instant coffee, and filtered coffee), cancer site (colon and rectum), and ethnic subgroup (Ashkenazi Jews [61.3% of the population], Sephardi Jews [21.4%], and Arabs [13.5%]). The study adjusted for daily total liquid and caloric consumption.
Higher coffee consumption was associated with lower odds of developing colorectal cancer: one to less than two daily servings (OR, 0.78; 95% CI, 0.68 - 0.90; P < .001), from 2 to 2.5 daily servings (OR, 0.59; 95% CI, 0.51 - 0.68; P < .001), and more than 2.5 daily servings (OR, 0.46; 95% CI, 0.39 - 0.54; P < .001). The dose–response relationships were statistically significant for cancers of the colon and rectum and for Ashkenazi Jews and Sephardi Jews
Arabs reported the highest total amount of coffee drinking (average 3.3 servings per day), followed by Sephardi Jews (2.1 servings per day) and Ashkenazi Jews (1.8 servings per day).
Limitations of the study include reliance of recall of coffee consumption going back 1 year, lack of standardization of serving sizes, and possible effects of avoidance of coffee by individuals with gastrointestinal diseases.