Following on from our article looking at the risk of bowel cancer and fibre intake, we now explore the link between red and processed meats and bowel cancer.
Many of us probably don’t think about our red and processed meat intake but it’s something we should be conscious about, from both a health and an environmental perspective. To start let’s take a look at what defines red and processed meat:
- Red meat – includes beef, pork, lamb, veal, venison and goat
- Processed meat – are any meats that have been preserved by curing or salting for example hams, sausages, bacon and salami
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).
