Evidence from many studies has suggested that lifestyle factors – including diet – play an important role in preventing colorectal cancer.
Now, an updated analysis of existing research has concluded that a number of dietary factors are strongly linked to colorectal cancer risk. As well, the researchers found that dietary patterns such as the Mediterranean diet and vegetarian diets offered protection.
Colorectal cancer is the third most commonly diagnosed cancer among men and the second most common among women worldwide.
About the research
For the analysis, published last week, researchers examined 45 meta-analyses of observational studies that investigated the association between diet and colorectal cancer risk. (A meta-analysis is a merging of data from many studies; it’s used to summarize the results of multiple studies.)
The researchers ranked the strength of the evidence according to five classifications: convincing, highly suggestive, suggestive, weak and nonsignificant.
Red meat, alcohol tied to increased risk, fibre and calcium protective
The evidence was “convincing” for the link between red meat (high versus low intake) and alcohol (more than four drinks per day versus little or none) and an increased colorectal cancer risk. In contrast, convincing evidence was found for a lower risk and higher (versus lower) intakes of fibre, dietary calcium and yogurt.
The evidence was graded “highly suggestive” for protection against colorectal cancer from a higher intake of total dairy products (milk, yogurt, cheese.)
It was also highly suggestive that a moderate alcohol intake (more than one up to three drinks per day) was associated with a greater risk of the cancer.
“Suggestive” evidence was found for protection from a higher intake of whole grains and adherence to a Mediterranean diet, pesco-vegetarian diet and semi-vegetarian diet. A Western diet, characterized by higher intakes of red and processed meat, refined grains and highly processed foods, was tied to a higher risk.
A pesco-vegetarian follows a mostly vegetarian diet but also eats fish and seafood. A semi-vegetarian, or flexitarian, eats a plant-based diet that occasionally includes meat.
These new findings add to a large body of evidence that suggests lifestyle modifications involving diet, as well physical activity and weight control, help guard against colorectal cancer.
Source: JAMA Network Open, February 18, 2021.
All research on this web site is the property of Leslie Beck Nutrition Consulting Inc. and is protected by copyright. Keep in mind that research on these matters continues daily and is subject to change. The information presented is not intended as a substitute for medical treatment. It is intended to provide ongoing support of your healthy lifestyle practices.