By now you’ve likely heard that on Monday the World Health Organization announced their decision to classify processed meat as a definite cause of cancer and red meat as a probable cause of cancer. The full article was published in the British medical journal, The Lancet Oncology, by The International Agency for Research on Cancer (IARC), the cancer agency of the World Health Organization. To come to their conclusion, 22 international scientists reviewed over 800 studies examining meat consumption and cancer.
So, what does this mean for all the bacon-lovers out there? Will eating ham sandwiches for lunch or an occasional grilled steak give you cancer? Let’s take a closer look at what the researchers actually said.
Reading the report, I noted that the authors were careful to state, right off the top, that “Red meat contains high biological-value proteins and important micronutrients such as B vitamins, iron (both free iron and haem iron), and zinc.” So…meat is good for us? AND it is going to give us cancer?!? What the heck do we do with that?!
First of all, let’s look at processed meats. Processed meats are any meat that is not sold fresh, but instead has been cured, salted, smoked, or otherwise preserved in some way (such as bacon, sausages, hot dogs, ham, salami, pepperoni, deli meats). The WHO scientists have concluded that people who eat processed meat have a significantly higher risk of developing bowel cancer. They have actually classified processed meat as a Group 1 carcinogen, the same as cigarettes. HOWEVER, it’s important to understand that this classification represents how confident the researchers are that processed meat causes cancer (very confident), but is not reflective of how much cancer processed meats actually cause (not as much as smoking).
This chart from Cancer Research UK clearly shows the difference:
This isn’t to say that you shouldn’t take the warning about processed meats seriously. The evidence shows that the MORE processed meat you eat the MORE likely you are to develop cancer as a result. Specifically, each 50g portion of processed meat eaten per day (i.e. two slices of ham) raises your risk of colorectal cancer by 18%. The IARC's Dr. Kurt Straif said, “For an individual, the risk of developing colorectal cancer because of their consumption of processed meat remains small, but this risk increases with the amount of meat consumed.”
As I said, these scientists have reviewed over 800 PAST studies. The link between red and processed meats and cancer is not “new” news. I have been advising clients to reduce or eliminate processed meats from their diets for years. That being said, the occasional BLT or ham sandwich is not likely to kill you. But, clearly the better choice is fresh unprocessed meats.
That brings us to red meat, which includes beef and lamb, but also pork (although the pork industry tries to sell it as “the other white meat”), which has also been linked to increased risk of cancer. The IARC has classified red meat as a Type 2A carcinogen, which means it “probably causes cancer”. Again, this is not new research and The Canadian Cancer Society has been advising people to keep their consumption of red meat down to 3 servings per week for years, based on the known association between red meat and colorectal cancer.
Researchers are still trying to determine exactly how red and processed meats cause cells to become cancerous, but the main theories centre around:
chemicals found within the meat itself as well as chemicals that are added to processed meats as a preservative (nitrates and nitrites).
cooking temperatures - cooking meat at high temperatures until it’s well done, such as on the BBQ or grill, causes the formation of potentially cancer-causing chemicals.
the high levels of iron in red meat, which may promote the formation of cancer-causing compounds.
Like I said, these are theories. We don’t really know for certain what the cause is, only the result: cancer.
So, are you wondering what on Earth you should be eating? What is safe? Doesn’t it feel like, at some time or another, everything supposedly causes cancer?! Really, the answer is simple. Eat Real Food: food that is as close as possible to its natural state; avoid processed carbohydrates (manufactured cookies, muffins, crackers, etc.) the same way you should avoid processed meats; eat plenty of vegetables and fruits; whole grains; raw nuts and seeds; beans and legumes; healthy fats like those found in olive oil, avocados and fatty fish; fresh fish; some white meat, if you like, and limited amounts of fresh red meat. Eat a wide variety of foods to get as many nutrients into you as you can! Oh, and while you’re at it, move around, stretch, go for a walk or a run. And don’t smoke. Eat well most of the time and then enjoy your BLT to the fullest when you have it.
PS. If you’re wondering how I handle processed meats in my house…well, my kids love bacon, so we have it very occasionally (less than once a month and it comes from a local producer) and once in a while I buy them ham from a local butcher/smoker at our farmer’s market, because they like to take ham sandwiches to school. Sometimes I buy prosciutto in the deli section of the supermarket and make them sandwiches with this. The ingredients list is: pork, salt. I never buy hotdogs, but my kids know that if they are offered one at a friend’s birthday party (for example) they are allowed to have it. In other words: Moderation.
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Bouvard V, Loomis D, Guyton K, et al. Carcinogenicity of consumption of red and processed meat. The Lancet Oncology. 2015.
full text: http://www.thelancet.com/journals/lanonc/article/PIIS1470-2045(15)00444-1/fulltext
Cancer Research UK: http://scienceblog.cancerresearchuk.org/2015/10/26/processed-meat-and-cancer-what-you-need-to-know/
Canadian Cancer Society: cancer.ca