In 2015, The World Health Organization (W.H.O.) released findings telling consumers that red meats are “probable carcinogens” and that processed meats are “carcinogenic to humans”. The processed meats finding was alarming and according the W.H.O. was “based on sufficient evidence in humans that the consumption of processed meat causes colorectal cancer”.
Generally speaking a meat is considered processed if has been transformed through salting, curing, fermentation or smoking and at a minimum this includes hot dogs, salamis and bacon. Processed meats were classified as Group 1 carcinogens; other agents in this group include cigarettes, arsenic, asbestos, plutonium. The W.H.O. conclusions were based on a study of studies, all of these studies were observational, based on self-reported food recall surveys.
But if eating bacon and other processed meats is as dangerous and risky as smoking or asbestos exposure, then why doesn’t the USDA’s Dietary Guidelines for Americans contain a warning that these foods are dangerous to your health and that they may cause death from cancer similar to cigarette packaging. Part of the explanation has to do with a failure to explain, and to understand, what the carcinogenic “groupings” mean as well as the alarmist headlines headlines that get written by health reporters.
Cancer is a complicated matter. To date, there’s no way of saying for sure that any particular food, substance or lifestyle will automatically result in any particular individual getting cancer. Instead we are left with a range of possibilities and risks. The World Health Organization has come up with a way of grouping agents into 1 of 5 groupings:
- Items in Group 1 are considered to be “carcinogenic to humans,” which means that we can be fairly sure that these things have the potential to cause cancer.
- Group 2A includes agents that are “probably carcinogenic to humans”. This basically means that there is some evidence that these things could cause cancer, but we can’t be sure.
- Group 2B means that a substance is “possibly carcinogenic to humans”. There’s no cut and dry guideline to tell the difference between ‘probably’ and ‘possibly’
- Group 3 includes agents that are unclassifiable with respect to carcinogenicity in humans
- Group 4 means that an agent is probably not carcinogenic to humans. There is only one substance (Caprolactam) in group 4
Relative vs Absolute Risk
Another part of the problem has to do with percentages, baselines and the difference between relative vs. absolute risk. These are nuances and scientific realities that are usually completely absent from the headlines.
For example, experts claim that people who smoke have a 2,500 percent greater lifetime risk of developing lung cancer compared to those who never smoke. Based on the associations identified by the W.H.O., eating two daily strips of bacon translates to about a 1 percent greater lifetime risk of getting colon cancer compared to those who never eat processed meats. The numbers say that an individual who consumes two strips of bacon daily has a 6 percent chance of getting colon cancer while the people who do not eat any bacon or processed meats have about a 5 percent colon cancer risk.
So it’s likely that eating too much processed meats will raise your risk rate somewhat but what the agency reported is that for every 50 gram portion of processed meat eaten daily your risk of getting colorectal cancer increases by 18 percent. An 18% greater risk seems high and relatively it is a statistically significant number. However, the increased risk is absolutely quite small because the baseline is that most everyone has a 5% risk of getting colon cancer regardless of whether they eat process meats or not.
Finally, it’s important to note that the exact causes of colon cancer (in fact most all cancers) remain shrouded in mystery. It’s most likely that the onset of cancer can attributed to a hodge-podge of causes including our environment, diet, lifestyles and perhaps most importantly our genetics.
Beyond the Cancer Issue:
Some critics of the “Bacon is Going to Kill You” message worry that a larger message may be lost. An ounce of bacon contains about 30 milligrams of cholesterol and is packed with sodium and nitrates. In addition, bacon and otehr processed foods are high in saturated fats which can raise cholesterol levels which can increase the risk of heart disease and stroke. It’s hard to say anything for certain but it’s likely that processed meats are not “health foods” and so the old idea of consuming everything in moderation may be a good rule to follow: