Alcohol. Cigarettes. Asbestos. Bacon?
The headlines came fast and furious last week, after a panel under the auspices of the World Health Organization (WHO) said there’s sufficient evidence that processed meats cause colorectal cancer. This puts bacon, hot dogs and sausages into the WHO’s Group 1 category, the same as substances like tobacco and asbestos. The same group also cautioned that red meats “probably” cause cancer.
The report was released by the International Agency for Research on Cancer (IARC). (1) The group comprises 22 experts from 10 countries who act as an independent advisor to the World Health Organization and evaluate the risks of environmental and lifestyle factors that might contribute to cancer. According to the report, there’s enough evidence to say that processed meats like sausages definitely raise the risk of colon cancer and that red meats “probably” do too.
We knew processed foods were bad, but is it also time to say goodbye to your favorite steakhouse? And will enjoying a sneaky slice of bacon or other processed meats every once in a while really cause cancer? Let’s take a bite out of this report.
What Is Red and Processed Meat?
Red meat is (surprise!) any meat that’s a dark red prior to cooking, also known as muscle meat. This includes beef, lamb, pork, veal, mutton, goat and horse.
A piece of processed meat have been cured, salted, fermented, smoked or somehow transformed to enhance flavor and improve preservation. Examples include hot dogs, pepperoni, corned beef, beef jerky or ham.
Link to Cancer?
Processed meats have been assigned to the WHO’s Group 1, or carcinogenic to humans. Under the WHO standards, that means there’s enough convincing evidence that an agent — processed meats, in this case — cause cancer. This is done by evaluating studies showing the development of cancer in humans.
Of course, “causing cancer” is a pretty vague statement. In particular, processed meats are believed to raise the risk of colorectal (or bowel) cancer. Colorectal cancer is the third most common non-skin cancer in the U.S. It’s estimated that 133,000 people will be diagnosed with the disease in 2015. Overall, someone’s lifetime risk of colorectal cancer is 1 in 20, about 5 percent.
However, there’s evidence that, among people who eat a large amount of processed and red meats, there is a higher risk. While red meat (and certainly processed meats) won’t make most lists of cancer-fighting foods, the news that it could be a cancer-causing food is disturbing. But is it true?
A 2011 study by the World Cancer Research Fund/American Institute of Cancer Research found that those who ate the most processed meats had about a 17 percent higher risk of developing colorectal cancer. (2) And according to the WHO, it’s estimated that for every 50-gram portion of processed meat a person eats daily, his or her risk of colorectal cancer increases by about 18 percent.
But how Do Processed Meats and Red Meat Cause Cancer?
So what causes the risk of colorectal cancer to increase? Researchers aren’t sure just yet. But while they haven’t pinpointed why processed and red meats cause cells to become cancerous, all signs currently point to chemicals found in the actual meat.
For a processed meat, this happens during the actual “processing.” While the meat undergoes its Cinderalla transformation from ugly slab of pork into pretty sausages and hot dogs, harmful, carcinogenic chemicals form. Good to know: It doesn’t matter if you purchase a bulk package of hot dogs for $0.99 or one exquisite, pampered pig slice of prosciutto. It’s the process, not the quality, that raises the risk of cancer.
With red meat, the concern is not how the meat is processed (since it normally isn’t) but rather the natural chemicals already present in the meats, plus carcinogenic chemicals that arise when the meat is cooked. Again, this means that the meat quality — farmer’s market, local butcher or factory-farmed meats — does not matter.
And neither does the preparation method — for instance, pan frying vs. grilling or barbecuing. There’s currently not enough data to know whether one way of cooking red meat is healthier than another. Some researchers believe high-temperature cooking might create compounds that contribute to red meat’s carcinogenic risk, but there’s not enough proof yet.
It’s also important to note that red meats are not currently in the same category as processed meats. They are in Group 2A, meaning they are “probably” carcinogenic, but there’s limited evidence to prove it at this time.
Can I Still Eat It?
Let’s review the facts: There’s enough evidence to say that processed meats definitely cause cancer and red meats probably do. And yes, this does put processed meats into the same category as other, more lethal-sounding substances. But can you still enjoy a hot dog (preferably organic) or a hamburger (preferably grass-fed beef) at a barbecue?
According to the panel, yes. The IARC’s categories are meant to distinguish how confident the group is that substances cause cancer. They do not assess the level of risk or how much cancer they cause.
So the IARC has enough evidence to say that diet high in processed meats cause cancer. They also have enough evidence to say that tobacco causes cancer. They are not, however, saying that the risk of cancer from processed meats and tobacco is equal. The graphic below from Cancer Research UK illustrates it well: While 86 percent of lung cancers stem from tobacco, just 21 percent of colorectal cancers do.
For processed meat, I’d advise that you skip it most of the time, as it contains harmful chemical compounds that may increase the risk of chronic disease. It’s much better to purchase, cook (!) and consume high-quality, grass-fed beef, in moderation. It’s a terrific, natural source of protein and iron, plus it actually contains cancer-fighting conjugated linoleic acid. Conjugated lienoic acid has shown immune-enhancing effects and anticarcinogenic activities in several animal studies. (3) Eating this quality of meat 1–2 times a week on any diet, including the keto diet, can be healthy and satisfying.
Be sure to look at serving sizes, too. The American Heart Association recommends two to three ounces of cooked, lean protein per serving. Not sure what that means? One meat serving size should be about the size of a bar of soap. Be sure to round out your plate with plenty of veggies and other nutrient-rich foods and vary sources of protein by including fish and poultry, too.
And while I’ve long advised against eating processed meat for a variety of reasons … no, that occasional slice of bacon or bratwurst link will not give you cancer.