Recently, the prospect that eating red or processed meat can increase your risk of cancer has been highly talked about in the media. Lean red meat is not only delicious, but also an important source of iron, zinc, vitamin B12 and protein. So how can something seemingly so harmless inflict such a serious disease? It does so via chemicals known as “N-nitroso compounds” that are formed upon digestion of these meats, which go on to damage the cells that line the bowel. Other likely factors include the high fat content in meat, as well as the fact that if meat takes up a large proportion of your diet- you tend to miss out on cancer protective foods, like fruit and vegetables and wholegrain cereals.
It is important to be aware of what kinds of meat are associated with this risk. Red meat includes beef, veal, pork, lamb, mutton and goat; whilst processed meat refers to meat that has been treated in some manner e.g. smoking, curing, or other processes that may be used to enhance flavor or improved preservation. No link has been shown between eating poultry and developing cancer, whilst some studies have even shown that eating fish can actually reduce the risk of bowel, prostate and breast cancers!
Secondly, this risk must be put into perspective. Compared to the well-known risk factor of smoking (see Ellie's last post) only 3% of cancers can be ascribed to red or processed meat compared to 20% caused by tobacco. Another way of looking at this is by examining the impact of these risk factors on the cancers with which they are most closely linked. Where tobacco is responsible for 86% of all lung cancers, red or processed meat causes 21% of bowel cancer cases. It's all relative- but is this a risk you’re willing to take?
According to the Scientific Advisory Commission on Nutrition, there’s no need to cut meat out altogether- but we should eat no more than 70g of red/processed meat per day. That’s equal to less than 3 slices of bacon.
To many, this doesn’t sound like much of an allowance… but it's actually much easier to achieve than you might think. Start by eating smaller portions of meat and bulking out your meal with extra vegetables, beans and pulses. You can also swap your red meat filling in your burger/sandwich for chicken or fish. Another great way would be to take part in the global ‘Meatless Mondays’ movement. With time, I think many people would be surprised at how easy this is to cut meat out completely, and may want to consider its carcinogenic status yet another one of the many reasons to go vegetarian. Along with benefiting your long-term health, you would also be contributing to solving many of the environmental issues that face our planet (livestock production accounts for over 18% of anthropogenic greenhouse gas emissions... which is more than emissions both transport and power generation!), as well as no longer funding an industry that causes so much animal suffering.
The carcinogenic status of meat has arisen from epidemiological studies that found associations between diets high in these meats and the incidence of certain types of cancer- in particular colorectal and bowel cancer. Epidemiological studies are those which analyse the patterns, causes and effects of health and disease in defined populations. Cancer Research at Bath (CR@B) are part of a research collaboration that aims to investigate the variation in European cancer survival rates, and why Britain has such low survival rates compared with the rest of the continent. One of their recent projects looked at the factors affecting GP’s decision to refer patients for further investigation. It is thought that our low survival rates are mainly due to a delay in diagnosis, and hence it is hoped that by pin-pointing and correcting the reason why, we can save more lives.