processed meats linked to cancer

WHO Says Processed Meats Rank Alongside Smoking as Cancer Causes

Fans of bacon, sausage and ham will be troubled by the World Health Organization’s (WHO) decision to categorize processed and cured meats in the same classification category as alcohol, arsenic, asbestos, and tobacco.

A report from the WHO states that evidence exists to justify ranking processed meats as a group 1 carcinogen as a result of findings demonstrating a causal link between consumption and bowel cancer.

But to understand exactly what this pronouncement means, and what the actual risk is to an individual considering limited or cutting off processed meat consumption, it’s important to delve into the details of the report to understand exactly what the WHO is saying.

Processed Meat’s Classification

The International Agency of Research into Cancer (IARC), the WHO’s division focused on cancer, states that processed meat is now a Group 1 carcinogen, meaning it’s definitively carcinogenic, joining a list of 119 other substances. The IARC also classifies substances as Class 2A (Probably carcinogenic), Class 2B (Possibly carcinogenic), and Class 3 (Not classifiable as to its carcinogenicity to humans), and Class 4 (Not carcinogenic).

Specifically, the IARC states that research demonstrates that daily consumption of 50 grams (or 1.8 ounces) of processed meat increases the risk of colorectal cancer by 18%.

It’s necessary to put this into context, though. The baseline risk of colorectal cancer over a person’s lifetime is roughly 5%. Increasing a 5% risk by 18% doesn’t equate to a 23% risk, however. Increasing a 5% risk by 18% results in a 5.9% risk. So it’s important to understand that for any individual person, the effect of consuming processed meats regularly is not particularly dramatic.

The IARC acknowledges this, stating that their focus is on the big picture. Increasing the risk of one person developing colorectal cancer from 5% to 5.9% is most times going to equate to nothing significant. However, take a population of 100,000,000 and increase the risk by 0.9%, and now there are 900,000 more people suffering from colorectal cancer over the course of their lifetimes. As a collective public health hazard, the IARC feels justified in classifying processed meats in it’s harshest category.

What Class 1 Means

classes of cancer causing meats

As previously defined, Class 1 substances are substances the IARC judges are definitely carcinogenic. But not all Class 1 substances are equal. Substances like tobacco and asbestos are incredibly carcinogenic, increasing a person’s chances of developing cancer by significant amounts. Processed meats, on the other hand, don’t increase an individual’s chances of developing cancer by a great deal.

So it’s a little bit sensationalist to view processed meats as being on the same level as some of the more troubling Class 1 substances simply because they share a classification. The classification system is more about certainty than it is about severity. What the IARC is saying is that they believe the scientific evidence is clear that processed meats have an effect on cancer rates.

Should You Eat Processed Meat?

In light of the IARC/WHO report, it’s possible that you might want to consider lessening your processed meat consumption if you consume it heavily. While consuming 50 grams of daily processed meats increases your risk of cancer by only 0.9%, at 250 grams per day your risk has nearly doubled, from 5% to 9.5%.

At a bare minimum, the research the IARC is citing shows that eating extremely large quantities of processed meats with regularity causes a marked increase in risk of developing colorectal cancer. Which means that moderation is important when it comes to consuming processed meats, like it is with most things in life.

Nutrition and dietary experts suggest that an ideal diet generally consists of large quantities of vegetables, moderate amounts of fruit, and a smaller quantity of grains, dairy, meats, and other sources of protein. If the meat you’re eating is processed, at the very least it ought to be in small enough quantities that you’re not increasing your cancer risk by a large amount.

It’s worth noting that the IARC has long classified red meat as a 2A carcinogen, meaning that they believe it to be probably carcinogenic, being linked to pancreatic and prostate cancer. And yet, experts in the field of diet and nutrition believe that red meat can have a place in a healthy diet. In truth, there are many things we encounter in our daily lives that raise our risk of developing cancer to varying extents, and it’s probably unavoidable. Even the air we breathe often times is carcinogenic. The key is avoiding substances that dramatically raise the chances of developing cancer.


If you’re worried about absolutely minimizing your chances of developing cancer, then it may be time to put down the daily bacon or sausage, as painful as that might be. The difference between 5% and 5.9% is small, but it is real. However, scaling back even to having processed meats once a week rather than daily would have a real effect in cutting down your risk of developing colorectal cancer.