On October 26, 2015 the World Health Organization (WHO) announced that processed meat was to be classified as Group 1, “carcinogenic to humans”, and red meat was classified as Group 2A, “probably carcinogenic to humans”.
The report is problematic and extensive mainstream and social media coverage has been sensational, unquestioning, and often flat out wrong.
Let’s start with the fact that of the 22 scientists from 10 countries on the panel, 15 voted for the conclusions that were published and 7 disagreed or abstained. Usually these panels seek consensus and one prominent FDA food safety scientist I discussed the results with was surprised at how far they were from consensus. Why the significant dissent and why publish such far reaching conclusions designed to change lifestyles and damage livelihoods with a vote of only 68%? And why publish only a summary? Where is the full report? Well, according to Andrew L. Milkowski, PhD, of the University of Wissconsin Meat Science & Muscle Biology Laboratory “Publishing the summary is their standard protocol. The full monograph will follow and based on history, that will take 6 months to 4 years.” Holy cow!
The first big problem is the paper lumps processed meats with red meats despite the fact that their evaluations of the risks were significantly different. Instead, in the media’s mind and thus the public’s mind, the two have been basted with the same broad brush. By their own definition, processed meat “has been transformed through salting, curing, fermentation, smoking, or other processes” while red meat is “unprocessed mammalian muscle meat, for example, beef, veal, pork, lamb, mutton, horse, or goat meat.” The key word is “transformed”. To be sure this is a media problem, but these folks should have some sensitivity to the fact that the media needs handholding when it comes to reporting science.
Many media reports equated the meats with cigarettes because they are both Group 1. As an NPR listener and donor I was shocked to read this headline on their website “Bacon, sausage and other processed meats are now ranked alongside cigarettes and asbestos as known carcinogens.” After several days they changed it.
Yes, Group 1 includes asbestos, solar radiation, air pollution, X-rays, plutonium. This does not mean that they are all equally dangerous and in fact cigarettes are vastly more dangerous. Getting hit by a bicycle or a train can kill you, and they are both hazards, but the risk is very different and the rate of lethality is very different. Elsewhere on the WHO website, not in the widely reported study, they explain that they evaluate cancer “hazards but not the risks associated with exposure. The distinction between hazard and risk is important. An agent is considered a cancer hazard if it is capable of causing cancer under some circumstances. Risk measures the probability that cancer will occur, taking into account the level of exposure to the agent.” They go on to say ” two substances or agents classified in the same Group should not be compared.”
In other words, these groupings are meant to convey how certain they are that something is dangerous, not how dangerous it really is.
NOTE: I wrote all this in October 2015, and finally in December 2019 WHO recognized their folly and decided that meats treated with nitrites needed to be studied separately from meats without this preservative. Of course nitrites have been studied in the past and found not guilty, but further studies with more modern methods are always welcome.
What are my odds?
So why didn’t they say so in the document so uneducated reporters who slept through science class in college would know better than to equate cigarettes with bacon? And why not explain the risk? I want to know what the odds are that I’ll get cancer if I eat two slices of bacon with my eggs every morning. The WHO panel says that eating 50 grams of processed meat (about 4 slices of cooked American style bacon) per day increases your odds of colorectal cancer 18%. And they leave it at that. What the heck does that mean?
The Center For Disease Control (CDC) says that over a lifetime your risk of colorectal cancer, the focus of the WHO research, is under 5%. Two slices of bacon will up the odds to less than 6% not 23% (5% + 18%) as some math challenged reporters have told us.
Heck, according to CDC data, the incidence of colorectal cancer is significantly higher in Pennsylvania than in Maryland. Should we conclude Maryland is bad for your health and evacuate everyone?
As bad as it is, colorectal cancer is rarely fatal. So why scare the public and give people the false impression that a hot dog is as dangerous as plutonium? If the WHO wants to be informative and influence behavior, start by producing meaningful statistics and release the info in a meaningful way because surely scientists aren’t so dumb that they don’t know that the media will misinterpret if they have a chance to.
Then there is the problem of their batting average. You’ve heard people scoff and say “everything is carcinogenic”? Well that’s pretty close to true if you ask WHO. Since 1971 they have evaluated more than 900 potential carcinogens and determined that only one, a chemical used in making nylon, is “probably not” carcinogenic.
In an article in the New York Times, Amy Elmaleh, director of Colon Cancer Canada, an advocacy group said there’s a “conversation to have about screening, which is a huge opportunity to prevent colon cancer.” Where was that?
The limitations of observational studies
The panel based its conclusion by studying existing studies, a practice called meta-analysis. Many media reports claimed they looked at 800 studies, but that’s not exactly true. They started with 800 and eliminated all but 15 red meat studies and 18 processed meat studies.
The studies they studied were all called epidemiological or observational studies. These studies are done by asking people to keep a food diary and a medical diary and then the scientists come along and study everything in the diaries to see if they can find correlations between how much bacon they ate and how many got colorectal cancer. But correlation is not causation. The causes of their cancers could have been many other things, called confounders. Perhaps the real cause was that these people were not eating enough vegetables with cancer inhibitors or any number of other variables. Or that people who eat a lot of hot dogs are doing or eating other things that are high risk. Or that people who avoid them are also exercising more. The scientists claim they took into account such confounders but it is also well known that people are really bad about keeping accurate food diaries. They forget to write it all down, especially if they are asked to keep diaries over many years. And they fib. Two donuts becomes one because they feel guilty and they don’t want their spouse to read the diary and give them grief.
Consumers, governments, and doctors should take epidemiological studies with a grain of salty pastrami, they are the lowest form of research. The gold standard for science is a focused study with minimal variables and a control group, perhaps one comparing vegetarians to omnivores over several decades. The problem is, as my wife, an FDA food safety scientist told me, “You can’t put humans in a rat cage.”
This restriction means that almost all nutrition and dietary research is crude. It is nowhere nearly as reliable as, say, physics, chemistry, agricultural, and other sciences where lab research can provide definitive answers. As a result, dietary recommendations are a moving target. Remember when butter was bad and margarine good? When we thought that the fat we ate ended up lining our arteries? When eggs were evil? All three of these shibboleths have been trashed in the past few years. I have written more on this subject in my article Food And Health, Some Thoughts About How Dietary Science And The Media Fail Us.
The red meat conclusion is not supported in their own report
My biggest complaint is the pronouncements about “red” meats. The report states that only 7 of the 15 “quality” studies they included found a correlation between red meat and cancer. That means that a majority of the studies found no correlation. So they concluded “no clear association was seen in several of the high quality studies.” They also stated “there is limited evidence in human beings for the carcinogenicity of the consumption of red meat.” The report also says “Red meat does have nutritional value too and is a major source of iron, zinc and vitamin B12.”
So how did they get from there to the conclusion that red meats are “probably carcinogenic to humans” and how did they assign the increased risk to 17% based on such sketchy evidence? And why have they included this data in with the processed meat data?
How can they lump beef, veal, pork, lamb, mutton, horse, or goat meat? The chemistry of beef and pork are pretty different. Just taste them or look at their colors. The iron part of hemoglobin, called the heme, gives it the dark purple pigment and is the subject of suspicion in some other studies. There is more heme in darker meats. So why paint veal or pork with taint? Why endanger people’s livelihoods with such sketchy evidence. If a crime is committed, police don’t just arrest everyone in sight, they find the criminal.
They mention that high temperature cooking has been shown to be a possible cause of carcinogens. So maybe the risk isn’t the meat, maybe it isn’t the heme, maybe it’s how some people cook it. If so, how dare they blame the meat? Ironically, the meeting was held in Lyon, France, one of the great food cities of the world and home to the culinary icon Paul Bocuse. A lunch at his restaurant might have caused someone to ask some impertinent questions. Maybe some of them did and they were among the dissenters.
Lousy WHO reporting = lousy media reporting = food scare
All the blame for a story poorly told should not go to WHO. Reporters have taken the opportunity to sensationalize the story. This is because so few media outlets can afford to employ science reporters capable of analyzing this sort of study nowadays, and partially because we consumers are so good at biting clickbait. No less a credible source than TIME magazine blamed nitrates and nitrites in precessed meats when other previous studies, even studies by WHO, have absolved them of guilt pointing out that we get 95% of our nitrates and nitrites from vegetables.
Sadly, in today’s evolving world of journalism, we are subjected to a steady bombardment of poorly reported news, facts, myths, research, and pseudo research. A direct result is that people are afraid of their food. Some of our silly diet regimens go beyond goofy to downright dangerous. Food anxiety will probably kill you faster than anything you can eat.
So before you become a vegetarian, think about this: Far more food-borne illnesses from bacteria, viruses, and parasites are caused by raw produce (46%) than by meat (22%), dairy and eggs (20%), and fish and shellfish (6%), according to the Center For Disease Control. That’s because anything raw is high risk. Lettuce and spinach in the fields are exposed to contamination from birds, bunnies, Bambi, and farm workers. CDC estimates that each year roughly 1 in 6 Americans (48 million people) get sick, 128,000 are hospitalized, and 3,000 die of foodborne diseases. So about 1 in 12 get sick from produce each year.
And remember, by far the most dangerous thing we do is get behind the wheel of our cars.
I have pointed this out before in a more detailed discussion of food and health, but it bears repeating: If you live to 79, the average life US expectancy, you will eat 86,505 meals. It is doubtful that a few bologna sandwiches, an occasional hot dog, or even a few bags of Cheetos will dent that. If you ate one hot dog a week for your entire life, that would be 4,108 hot dogs out of 86,505 meals. By the way, in Spain, where their cured meats are treasured, life expectancy is 82 years.
Every good dietician and physician will tell you that Mom was right: Eat a balanced diet and don’t overdo anything, and I might add, that means anything, from sausages to salads. Gregory Bloom, writing in the meat trade magazine Meatingplace suggests “Perhaps we should just stick a hyperbolic, one-size-fits-all label on all consumables that says, ‘Warning, the Surgeon General and the WHO have determined that everything you consume in excess is harmful to your health and will eventually kill you. No matter what you consume in excess, in the end, you will not survive it.'”
The sad part is that the WHO has damaged its reputation. They had a great opportunity to educate and communicate and expand their influence. Instead they went for sensational headlines. Reading news coverage online is almost uniform: People are unimpressed. They knew they shouldn’t eat too much processed meat, red meat, candy, lettuce, whatever. And most are not about to swear off their bacon and beef. The ones who are most alarmed seem to be the ones who have already given up gluten, soy, sugar, fat, and fun.
As I have said before: We all want a long, healthy life, but life should not be an ascetic journey of denial of pleasure so that we can arrive at the end with a perfect body. I plan to watch my diet and take everything in sensible proportion, but deny myself no opportunity for great pleasure because of some research paper that will be invalidated in a few years. As Dr. David Katz, the founding director of Yale University’s Prevention Research Center has said “The cold hard truth is that the only way to eat well is to eat well.”
I plan to arrive at the pearly gates with a bottle of wine in one hand and a rib bone in the other, laughing and regaling anyone within earshot with tales of how great my life was. See you there.
Some related links
- The whole WHO report
- WHO Press Release
- WHO Q&A on the carcinogenicity of the consumption of red meat and processed meat
- About WHO monographs and what they mean
- New York Times was an exception and they got it mostly right
For more information, contact WHO Spokesperson Gregory Härtl at email@example.com