Does eating processed meat cause cancer?
Many of us enjoy some bacon for breakfast or a sausage roll at lunchtime, but could eating these processed meats increase our likelihood of getting cancer? We asked 3 experts in nutrition and public health, 'Does eating processed meat cause cancer?', here is what we found out...
Does eating processed meat cause cancer?
What are processed meats?
Processed meats are food items that contain meats which have been preserved. Processed meat may have been cured, smoked or had preservatives added to it. Processed meats include sausages, bacon, hams and salamis. Minced meat, for example that used to make hamburgers, is not considered processed meat unless it has also had preservatives added to it.
What is the evidence that processed meat is linked to cancer?
Dr Tim Crowe, a nutrition expert from Thinking Nutrition, says “People who eat a diet low in processed and red meat are less likely to develop bowel cancer. This link is nothing new and the 2015 International Agency for Research on Cancer (IARC) report investigating how likely red meat and processed meats are to cause cancer was a summary of the research to date. The IARC concluded that processed meat and also likely red meat are linked to causing colorectal cancer.”
These conclusions were based on several studies that looked at the incidence of colorectal cancer (also called bowel cancer) in people who ate varying amounts of processed and red meats. Many of these studied found a positive association – i.e. they found that people who ate more processed meat were more likely to develop this type of cancer.
How does processed meat increase cancer risk?
Dr Crowe says “The answer isn’t certain, but several plausible mechanisms have been proposed.”
He goes on to describe, “The first culprit is the haemoglobin pigment that gives red meat its colour. Haemoglobin breaks down to a family of chemicals called N-nitroso compounds in the gut. These compounds can damage the cells that line the bowel, causing them to divide and replicate more.” N-nitroso is particularly concentrated in processed meats such as bacon, sausages and hot dogs.
Dr Crowe says “A second candidate could be the actual cooking process of red meat itself, especially grilling or barbequing. The combination of high temperatures and charring of meat produces chemicals on the surface of the meat that may increase the risk of colon cancer. One simple way to reduce the formation of these compounds is to marinate meat first. Think of it as a protective layer on the meat, but with the added bonus of extra taste.” Some of the chemicals that are produced during cooking processed meats include MeIQx and PhIP. These chemicals are known as mutagens, meaning they can cause genetic mutations, which are the precursors for cancers.
How worried should I be about my processed meat intake?
Dr Gideon Meyerowitz-Katz, an expert in public health from Wollongong University in Australia, says “There is good evidence that eating processed meats is likely to increase the risk of bowel cancer. It is worth pointing out that, although the reported risk is 18%, this is a relative risk and therefore not that useful for individuals. The absolute risk increase in the rate of cancer from eating 2-3 rashers of bacon per day is about 0.2%, which means that for every 1,000 people who eat extra bacon, about 2 will develop bowel cancer who otherwise wouldn't. At a population level, these risks are quite important, but for individuals it's hard to say whether the risk of eating processed meat is particularly meaningful.”
Dr Crowe adds that “even the highest-level committee members of the IARC were not saying that if you eat a sausage you are a candidate for cancer. What they were warning about was that if processed meats were a daily feature of your diet, your risk of bowel cancer would go up.”
How often, how much and what types of processed meats you eat will all affect your cancer risk. Not all processed meats are the same - some meat items are processed using methods such as drying which doesn’t add any extra chemicals which may be linked to cancer. The way you cook your meat also affects its potential cancer risk.
Dr Crowe makes a suggestion: “While a sausage sandwich every now and then isn’t going to do you much harm, if you are eating a lot of processed and red meat then it could be a good idea to try to cut down. The World Cancer Research Fund recommends eating no more than 500 grams of cooked red meat per week. And if you eat processed meat, really keep that to a minimum. Chicken and fish make excellent alternatives to red meat. Or you could even consider having more vegetarian meals in your diet.”
If you often eat processed meat, try swapping out your next sausage with a chicken, fish or vegetarian option.
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