The International Agency for Research on Cancer (IARC), an arm of the World Health Organization lists processed meats in its 鈥淐ategory 1,鈥� reserved for substances known to cause cancer in humans. There is really nothing all that noteworthy here except for the official classification. Unofficial advice about minimizing processed meat has been dispensed by nutritional scientists for a long time. And for good reason.
First, let鈥檚 clarify what is meant by processed meat. Grinding meat into hamburger does not result in processed meat. But smoking, fermenting, or adding chemicals such as salt or nitrites to either extend the product鈥檚 shelf life or change its taste does. We鈥檙e talking about bacon, sausages, hot dogs, salami, corned beef, beef jerky and ham as well as canned meat and often meat-based sauces.
The evidence that these tasty morsels are linked to cancer comes from observational studies, which of course do not prove cause and effect. But they are quite consistent in demonstrating that populations that consume lots of processed meats have higher cancer rates, particularly colorectal cancer, even when corrections are made for smoking, other foods eaten, and activity levels. Furthermore, there are theoretical and experimental foundations for declaring some components found in processed meat, like polycyclic aromatics, heterocyclic amines, nitrites, insulin-like growth factor and heme-iron, carcinogenic.
The evidence is certainly not ironclad, but science rarely is. It comes down to making educated guesses and evaluating the downside of such guesses. There is no significant downside to limiting processed meat, especially if it is replaced by plant products. But the significant question to ask is how much can we reduce our risk of colorectal cancer by robbing our taste buds of the taste of bacon and such? The risk of this cancer in the general population is roughly six in a hundred. After poring through some 800 peer-reviewed publications, IARC estimates that eating 50 grams of processed meat every day over a lifetime increases risk by about 18%. In other words, if a hundred people follow such a regimen over a lifetime, there will be seven cases of colorectal cancer instead of six. So, for an individual, the chance of being afflicted with colon cancer because of eating processed meats is about 1 in 100. That is a very small risk, but because there may well be millions of people following such a diet, the impact on the population can be significant, in IARC鈥檚 estimate, about 34,000 cases a year. 聽
What do we do with this information? A one in a hundred chance is not insignificant and it makes sense to try to reduce it. That means consuming less than 50 grams of processed meat a day on average. To do that we need to keep some numbers in mind. Two to three strips of bacon add up to 50 grams, as do two slices of ham, 4 slices of salami or one hot dog. Remember though that we are talking averages here. A couple of hot dogs, a salami sandwich and a couple of bacon and egg breakfasts a week is not a great risk. But if you have a smoked meat sandwich, well, you have used up your weekly allotment.
In case you are considering switching to cheese from meat, prompted by the IARC classification, you may be going from the frying pan into the fire. At least according to Dr. Neal Barnard, founder of the Physicians Committee for Responsible Medicine (PCRM). He claims that casein in cheese is like crack. Actually, PCRM is an animal rights activist group that wants to eliminate all animal experiments and of course the consumption of any animal products. The group is myopic, looking at and publicizing only studies that mesh with its quasi-religious views. I think a ham and cheese sandwich would do to Barnard what a cross does to a vampire.
So, according to IARC we can't eat meat, according to PCRM we can't eat cheese, according to cardiologist William Davis we can鈥檛 eat grains, according to the Environmental Working Group (EWG) we can鈥檛 eat conventionally grown vegetables or fruits, and according to pediatric endocrinologist Robert Lustig, sugar is poison. So that leaves our nails to chew on. But wait, only if they have no nail polish that contains endocrine-disrupting phthalates.
