Every day we are faced with decisions that affect our health. From the time we wake up to when our heads hit the pillow, we are bombarded with these small health "dilemmas." Should you wake up early and forego sleep to get in a cardiovascular workout? How many cups of coffee should you drink? And is it okay to use a sugar substitute? Is the salad with nuts, cheese, and fruit a better choice for lunch than the turkey sandwich? Is that extra glass of wine tonight really going to hurt you?
Every time you turn on the TV, log onto Facebook or Twitter, it seems that there is a new study renouncing one habit and touting another. One day caffeine leads to increased risk of death, another day it improves memory. In an era that has shifted the responsibility for healthy decision making onto the patient, combined with an endless supply of "information" and "research" via social media, it is easy to feel overwhelmed.
And now there is one more report to add to the mix: On Oct. 25, the World Health Organization (WHO) proclaimed that processed meat (i.e., bacon, hot dogs, deli meat), and likely red meat, is a carcinogen and belongs in the same category as tobacco. Although a major earthquake had just occurred in South Asia, my newsfeed was filled with posts and outrage about bacon!
So what does this new report mean? Do you really need to give up bacon (and other processed meats) forever? If you don't, will you get cancer? And is bacon really as bad for you as tobacco?
First of all, did you really think bacon and processed meats were healthy? Seriously? I think any reasonable adult would agree that eating large amounts of processed meats is bad for your health. Processed meats are generally laden with fat and salt which can, in turn, contribute to obesity, high blood pressure and cardiovascular disease... which can all kill you! So the fact that eating processed meat regularly is bad for your health is not news.
Second, let us review some boring biostatistics (sorry). The main conclusions from this report were based on meta-analysis published in 2011. A what? A meta-analysis pools together a lot of smaller studies in order to get a larger sample size (i.e., more study participants). All of the studies included in the meta-analysis followed patients forward to try to correlate the amount of processed and red meat they were eating and whether or not they developed colorectal cancer. The problem inherent in this design is that dietary habits are hard to capture. Think about what you ate last week. Now try to quantify how many servings of meat, dairy and vegetables you think you ate? It's hard to do for just one day! In addition, while you can try to control for things such as exercise and alcohol intake, it is not perfect and there is likely bias. The other problem in a meta-analysis is that you are comparing multiple studies that may have been carried out in different ways -- in essence you are comparing apples to oranges (which are shown to be good for your health) which may affect your results. Unfortunately, the gold standard study, a randomized controlled trial where you assign people to eat processed meat or no processed meat would be impossible to conduct so this meta-analysis is the best data we can hope for.
Regardless of potential biases in the data used for the new WHO recommendations, it is (sadly) likely that eating processed meats increases your risk of colon cancer (again it also increases your risk of obesity and cardiovascular disease!). The question, though, is how much does it increase your risk? Many things increase your risk of cancer and/or death and you likely still do them anyways -- have you ever been in a moving car without a seatbelt? Colon cancer risk varies by individual but the average American has about a 5 percent lifetime risk of developing colon cancer (you can calculate your personal risk here). These studies showed that eating 50 grams of processed meat (1 regular sized hot dog or 2 slices of bacon) every day increases that 5 percent baseline risk by about 18 percent (5 x 1.18), which is pretty small in my book. However, if you already have a high baseline risk of colon cancer (family history, inflammatory bowel disease), you may want to take every measure possible to reduce or not increase your risk further.
So finally, since the WHO placed processed meat in the same category as tobacco, is it just as bad for you? Hopefully, I've clarified this part a bit in the paragraph above. While eating processed meats increases your risk of colorectal cancer by 18 percent (again multiply your baseline risk by 1.18), tobacco increases your risk of lung and other cancers by over 1,900 percent (that's over 20 fold, multiply that baseline risk by 20)! The worst thing you can do for your body and health is smoke! That said, what does it mean that processed meats are in the same carcinogen category as tobacco? Both are in Class 1, which means they are proven to be carcinogenic to humans, although they may have different risks of causing cancer. What else is considered to be a class 1 carcinogen? The sun, alcohol, air pollution, sex (via human papilloma virus), and tamoxifen (which is actually used to prevent breast cancer recurrence). In other words, it would take quite a lot of effort to avoid class 1 carcinogens all together. (By the way, shiftwork that involves circadian disruption, aka being a doctor, is classified as Group 2A -- probably carcinogenic to humans.)
The take home message from this is that life is a balance of risks and benefits. Research studies should be interpreted cautiously and taken with a grain of salt (but not too much). You likely engage in some form of "risky" behavior every day (I know you don't wear sunscreen every time you step outside). It is important to understand these risks but to also put them into the context of the rest of your lifestyle and health. Relaxation and happiness are also important for health and going crazy trying to follow every new recommendation will likely leave you frustrated, stressed and eating only kale salads for the rest of your life. So for now I will do as Michael Pollan says, "Eat food. Not too much. Mostly plants..." and occasionally bacon.