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Foods and Colorectal Cancer Risk: Update from the World Cancer Research Fund

6/27/2017 2:20:43 PM
The World Cancer Research Fund International (WCRF) Continuous Update Project published a review of evidence in 2011 related to risk factors for colorectal cancer. The report concluded that red and processed meat, alcoholic drinks in men, body fatness, abdominal fatness, and adult attained height increased the risk of colorectal cancer, whereas physical activity and foods containing fiber decreased the risk of colorectal cancer. The report suggested probable protective effects of alcoholic drinks in women, garlic, milk, and calcium.
 
The WCRF updated the systematic review and meta-analysis in 2017 with studies published through May 2015. A total of 400 individual study estimates from 111 unique cohorts were included in the analysis. Relative risks (RRs) of colorectal, colon, and rectal cancer were calculated for specific food groups and beverages. Here we report the RRs for colorectal cancer in the overall population. More specific data related to colon cancer, rectal cancer, men, and women can be found in the complete report.
 
Foods associated with increased colorectal cancer risk were red meats, processed meats, and alcohol. Red and processed meats as a group increased the risk of colorectal cancer by 12% (RR for 100g/d increment=1.12; 95% CI, 1.04-1.21); processed meat alone increased the risk by 18% (RR for 50g/d increment=1.18; 95% CI, 1.10-1.28); and the association between red meat alone and colorectal cancer was marginally significant (RR for 100g/d increment=1.12; 95 % CI, 1.00-1.25). Each increase of 10g/d of alcohol intake (equivalent to 1 standard drink) increased the risk of colorectal cancer by 7% (RR=1.07; 95% CI, 1.05-1.09).
 
Foods associated with decreased colorectal cancer risk were whole grains, dairy products, vegetables, and fish. Whole grains decreased the risk of colorectal cancer by 17% (RR for 90g/d=0.83; 95% CI, 0.79-0.89). Dairy products decreased the risk of colorectal cancer by 13% (RR for 400g/d=0.87; 95% CI, 0.83-0.90). Consumption of 100g/d of vegetables was associated with a slightly decreased risk of colorectal cancer (RR=0.98; 95% CI, 0.96-0.99). An increase of 100g/d of fish was associated with an 11% decreased risk of colorectal cancer (RR=0.89; 95% CI, 0.80-0.99) based on a single study.
 
Foods not associated with colorectal cancer risk were coffee, fruit, poultry, cheese, tea, and legumes. The authors acknowledge that these results may be due to a lack of statistical power to detect any associations.
 
Overall, the results of this updated report are consistent with the findings reported in 2011. The data reinforce that red and processed meats as well as alcoholic beverages increase the risk of colorectal cancer, whereas whole grains and dairy products decrease the risk.
 
Reference: Vieira AR, Abar L, Chan D, et al. Foods and beverages and colorectal cancer risk: a systematic review and meta-analysis of cohort studies, an update of the evidence of the WCRF-AICR Continuous Update Project. Ann Oncol. 2017