Cereal Fibre - beyond roughage

New research highlights importance of grains in the diet

A new review has provided more evidence of the importance of including a range of different fibre sources in a healthy diet, including grain foods. The meta-analysis of cohort studies reports that fibre from grain foods and particularly wholegrains is associated with reduced risk of bowel cancer, but fibre from fruit and vegetables does not have a significant association. Grain foods may be one key to help unlock the puzzle of our rising rates of bowel cancer.

Bowel cancer. It’s not really dinner time conversation, but maybe it should be. Colorectal cancer is one of the most common forms of cancer in Australia, affecting 1 in 12 people under the age of 85 and leading to the death of almost 80 people every week.

The good news is that if it is found early there is a high chance of survival, and even better news is that making smart choices about what you eat today could help reduce your chances of developing bowel cancer later.

Previous research has shown that people who eat higher-fibre foods, like fruit, vegetables and wholegrains, are less likely to develop a range of diseases, including bowel cancer. Recently, a systematic review and dose-response meta-analysis of 25 prospective cohort studies went one step further to determine if some high-fibre foods were better choices than others when it comes to preventing bowel cancer.

From an analysis of the eight cohort studies that reported on cereal fibre intake, the review found that for every 10g of cereal fibre, the risk of developing bowel cancer was reduced by 10% (RR=0.90 CI 0.83 – 0.97). The study also considered the effect of wholegrain foods including wholemeal bread, oats, wholegrain breakfast cereal, wholegrain rye bread, and brown rice. People who ate 3 serves of wholegrain foods per day were 17% less likely to develop bowel cancer than those people who didn’t eat wholegrain foods. Interestingly, the study found that fruit and vegetable fibre did not significantly help protect against bowel cancer (RR= 0.93, CI 0.82-1.05 and RR=0.98, CI 0.91-1.06 respectively).

The way in which fibre helps reduce the risk of colorectal cancer is due to several effects in the gut, but the precise mechanism is not yet fully understood. We know that fibre helps keep you regular which has many health benefits, but more recent research has also linked fibre in some grain foods to higher levels of bacteria in the bowel that produce short-chain-fatty-acids including butyrate. Recent research by the CSIRO found that increasing the intake of rye bread lead to significantly high levels of butyrate which is believed to help prevent cancer cell proliferation in the bowel.

According to the World Cancer Research Fund scientific review in 2011, other foods that may help fight bowel cancer are garlic, milk, and calcium. Other ways to reduce your chances of getting bowel cancer is to get at least 30 minutes of exercise every day, and to limit the amount of processed meat (like salami) in your diet.

References:
www.aihw.gov.au/cancer/
http://www.bowelcanceraustralia.org/