Are you worried that eating red meat and processed meat will increase your risk of cancer? Red meat receives a bad wrap for causing cancer. But is this really true? In this article, we will explore if red meat really does increase your chances of getting cancer or not.
In 2015 the World Health organization (WHO) classified processed meat as a class 1 cancer causing agent. This puts processed meat in the same category as asbestos, tobacco, and arsenic. Examples of processed meat include hot dogs, ham, bacon, sausages, corned beef, and beef jerky as well as canned meat and meat-based preparations and sauces. Most processed meat contains red meat but some also contain poultry. (1, 2, 3)
Red meat refers to muscle meat such as beef, veal, pork, lamb, mutton, horse, and goat that hasn’t been changed through salting, curing, fermentation, smoking, or other processes to enhance flavour or improve preservation. Red meat was listed as a class 2A cancer causing agent (carcinogenic). This suggests that it is “probably carcinogenic” to humans.
Weak association between red meat consumption and cancer
Most studies on red meat consumption and cancer will claim there is an association between the two. However, a reputable critical review of these claims says otherwise. (4) The authors looked at 35 of these studies and found lots of problems.
- Risks of eating red meat and cancer aren’t significant statistically and there is a lack of a clear dose-response trend. This means there is a weak association between red meat consumption and cancer and there is no relationship between the amount of red meat consumption and cancer. If red meat really did cause cancer, there would be an increase in cancer rates as red meat consumption increased. But that’s not what we’re seeing. In fact, some studies show a decrease in cancer rates in people who ate the most red meat. (5)
- Results of studies on red meat and cancer vary. Some studies show people who ate more red meat had less colon cancer while people who ate more red meat had more rectal cancer. As well, red meat has different effects in men and women. The association between red meat consumption and cancer in men is weakly elevated. In women, there isn’t a positive association at all. Without clear explanations on why the results vary, the likelihood of red meat causing cancer is reduced.
“Healthy user bias”
Probably one of the biggest problems with studies linking red meat and cancer is because of the “healthy user bias”. This means people who engage in an activity or behaviour that is perceived to be healthy are likely to engage in other activities and behaviours they perceive to be healthy. Likewise, people who engage in an activity or behaviour that is perceived to be unhealthy are likely to engage in other activities and behaviours perceived to be unhealthy.
Red meat has been perceived to be unhealthy to eat for over fifty years now in the industrialized world. Many studies have shown that people who eat more red meat also have a tendency to smoke and drink more, eat fewer vegetables and fruits, exercise less, and engage in other unhealthy behaviours that could cause cancer.(6, 7, 8, 9, 10)
What does a typical meal with red meat look like in North America? A burger with a white flour bun, chips or french fries cooked in rancid, processed vegetable or seed oils, and a soda pop loaded with fructose corn syrup (refined sugar). So how do we know it’s not the other foods or other unhealthy habits causing the increase in cancer versus the red meat?
The typical North American red meat meal consists of a burger between a white flour bun, chips or french fries cooked in rancid, processed vegetable or seed oils, and a soda pop loaded with fructose corn syrup (refined sugar). So how do we know it’s not the other foods or other unhealthy habits causing the increase in cancer versus the red meat?
It’s pretty hard to design a good red meat and cancer study where you have enough people in it with similar ages and characteristics, and we strictly control their diet, exercise, and other lifestyle factors. To determine if red meat truly caused cancer, we would have to isolate people in the study for decades and feed one group more red meat and the other group less. It’s just not feasible. (11)
We are then left with observational studies to determine whether red meat causes cancer or not. However, observational studies can only demonstrate an association or relationship between red meat and cancer, not causation. Sometimes the association will end up being the cause, and sometimes it’s not.
What is your risk of developing cancer if you eat processed meats?
About 3 extra cases of bowel cancer per 100,000 adults. (2) This means you have a 1 in 33,000 chance of developing bowel cancer if you eat processed meats.
Here’s some perspective. Remember WHO classifies smoking cigarettes (tobacco) in the same class as eating processed meats. So how does eating bacon and other processed meats compare to smoking cigarettes? Tobacco smoke is loaded with known cancer causing chemicals and increases the risk of lung cancer twentyfold. (12) In Canada, about 1 in 12 Canadians (8,333 per 100,000) will be diagnosed with lung cancer. 85% of lung cancer cases in Canada are due to smoking. That’s about 7,000 cases of lung cancer per 100,000 people. (13)
At this point in time, there is not enough evidence to show that eating processed meat is a significant risk factor for cancer. There’s even less evidence that fresh red meat poses a risk for cancer.
In my opinion, eating processed and cured meats periodically does not pose a significant health risk. This would be especially true if you’re eating real nutrient dense foods regularly, exercising regularly, minimizing mental stress, etc. As well, eating fresh red meat (especially wild or pasture raised), in my opinion, is part of the real nutrient dense foods we should be eating regularly. There is little evidence we should be limiting these foods at all. This is especially true if we use gentle cooking methods (rather than charring it) and when you eat organ meats and cheaper cuts of meat. I will expand on this topic in another future article.