Eating more whole grains reduces colorectal cancer by only 17% (RRR)

Our new report found, for the first time, that eating three servings (90g) of whole grains a day reduces the risk of colorectal cancer by 17 per cent.

The report evaluated all of the research worldwide on how diet, weight and physical activity affect colorectal cancer risk and also confirmed that the following increase colorectal cancer risk:

• Eating processed meat, such as bacon or salami
• Eating too much red meat, (over 500g cooked weight a week), such as beef or pork
• Being overweight or obese
• Drinking 2 or more alcoholic drinks a day, such as two glasses of wine or two measures of spirit

The report also found that being physically active decreases the risk of colon cancer.

40 cigarettes a day doubles the risk, it means 100% RR increase...

16% RRI with processed meat

12% of RRI with red and processed meat

12% of RRI with red meat and a great heterogeneity (https://www.meta-analysis-workshops.com/download/common-mistakes1.pdf) 

In all of those meta-analysis apart methodological problems, we see very weak relative risk increase or reduction. As all those studies are observational it does not mean that a causal relationship is involved.