Bowel Cancer: Red & Processed Meat

What's the evidence?
Many studies have been done to research the link between red and processed meats and colorectal cancer. A 2011 meta-analysis of prospective studies concluded that "high intakes of red and processed meat is associated with significant increased risk of colorectal, colon and rectal cancers." The meta-analysis found that "the risk increase in colorectal cancer estimated in linear dose-response models was 14% for every 100 g/day increase of total red and processed meats, 25% in colon cancer, and 31% in rectal cancer. These results are consistent with those of the highest versus lowest meta-analyses."

What causes the increased risk of cancer?
This is still an area that scientists are researching. It`s thought that a chemical in red meat "“ haem (which gives meat its red colour) is broken down in our digestive system to form N-nitroso compounds which are found to damage the cells lining the bowel. Processed meats contain nitrites and nitrates and it`s thought that they also increase exposure to N-nitroso compounds.

There are also suggestions that the fat in red meat and cooking meats at high temperatures could also impact on colorectal cancer risk. Those who have a diet high in red and processed meat may also eat fewer of the foods that could help reduce the risk of cancer (fruits, vegetables, pulses).

What changes should I make to my diet?

Red meat is an important source of iron, zinc and B vitamins, so you don`t need to completely remove it from your diet. However if you consume a lot of it, and processed meat, on a regular basis then you should consider cutting down. Government guidelines advise that if you eat more than 90g (cooked weight) of red and/or processed meats a day you should cut down to 70g or less.

Average red and processed meat portions (out of home portions could be larger):

• 2 rashers cooked bacon = 50g
• 2 grilled thick sausages = 98g
• 2 slices of premium ham = 65g
• A portion of cooked mince beef = 100g
• 4 slices of a small salami = 25g

References
1. Iron and Health, SACN, 2010.
2. Chan D S M, Lau R, Aune D, Vieira R, Greenwood D C, Kampman E, Norat T. Red and Processed Meat and Colorectal Cancer Incidence: Meta-Analysis of Prospective Studies.; 2011; 6(6): e20456, PloS One (online).
3. Cancer Research UK: http://scienceblog.cancerresearchuk.org/2015/10/26/processed-meat-and-cancer-what-you-need-to-know/ (access online April 2017).