Bowel cancer is one form of cancer where diet and lifestyle choices play a big part in determining a person’s risk of being diagnosed with it. Medical researchers have now put some hard numbers to how much this cancer can be prevented by following specific lifestyle recommendations. Associate Prof Tim Crowe, from the School of Exercise and Nutrition Sciences, explores this topic further.
Bowel cancer (also called colorectal or colon cancer) is the second biggest killer of Australians from cancer each year. Dietary factors alone are thought to explain almost half of bowel cancer risk, with physical activity (or lack of) around another quarter followed by genetics and family history. Processed meat, obesity (especially fat around the abdomen), smoking and alcohol are the diet and lifestyle factors that are considered to have the most evidence for being linked to colorectal cancer.
With such a large influence that diet and lifestyle has on a person’s risk of developing bowel cancer, combining these factors into a simple lifestyle assessment score could be an important public health initiative in identifying people at greatest risk of the disease.
Early detection of bowel cancer through screening has a dramatic impact on cutting mortality from the disease, so knowing who may benefit from earlier and more frequent screening would be valuable. Knowing what your individual risk assessment score was would also allow for targeted counselling on effective lifestyle changes.
Researchers from Denmark have evaluated a simple lifestyle risk assessment score for bowel cancer and estimated the number of cancer cases that could be linked to the risk score. The five factors included were physical activity, waist circumference, smoking, alcohol consumption and diet. Diet itself was an umbrella term which covered dietary fibre, fat, red and processed meat, and fruit and vegetable consumption.
The risk assessment was applied to an epidemiology model involving over 55,000 adult Danish men and women who were part of a long-term study looking at diet and cancer risk. The full study was published in the British Medical Journal.
After some complex statistical and mathematical modelling, there was a clear trend for a lower risk of bowel cancer for each lifestyle recommendation a person met. Adhering to guidelines for all five risk factors could have potentially prevented 23% of the cases of bowel cancer. Even if all the people in the study had of met just one recommendation, this could have markedly reduced the cases of colorectal cancer by 13%.
Recommendations to live by
So what where the healthy lifestyle guidelines used for each of the five risk factors?
- Not smoking at all
- Being physically active for at least 30 minutes per day
- Having 7 or less alcoholic drinks per week for women and 14 for men
- Having a waist circumference below 88 cm for women and 102 cm for men
- Eating more than 600 grams of fruits and vegetables per day
- Eating less than 500 grams of red and processed meat each week
- Having at least 25 grams of fibre per day
- Reducing fat to less than 30% of the energy in the diet.
What it all means
Most cases of bowel cancer are not inevitable and a person can significantly cut their risk by making changes to their diet and lifestyle today to reap rewards well into the future. The findings from this latest research tell an important message on where the focus on positive lifestyle changes should lie.
You can connect with Tim on his blog.