There has been a lot of misinformation and confusing coverage around the release of the World Health Organization (WHO)’s findings linking processed and red meat to cancer. The science isn’t new but the vastness of the research collected by such an influential organization has led to a subsequent media frenzy. As a result, most people don’t really know where they stand, or whether they should take red meat off their shopping list altogether.
Is red meat linked to cancer? The short answer is, yes, processed red meat is, but scientifically, we don’t know for sure about natural red meat yet. However, experts certainly believe it is, and there’s a good reason for that…
The Study
Processed meat and red meat were high priorities when an international advisory committee met in 2014. The committee recommended an evaluation by the International Agency for Research on Cancer (IARC) Monographs Program. That recommendation was based on studies of epidemics that suggested small increases in the risk of cancer may be associated with high consumption of red meat and processed meat.
This news isn’t actually new. It has been brewing and trickling out in individual studies for years now, and it has been widely accepted for a long time that meat can increase the risk of bowel cancer. This collaboration of research, however, is significant because it comes from the IARC. Their findings carry weight, and are listened to by governments and regulators. The working group considered more than 800 studies that investigated associations of more than a dozen types of cancer with the consumption of red meat or processed meat in many countries and populations with diverse diets. The most influential evidence came from large studies conducted over the past 20 years.
The Findings
This is the area that has become very clouded, with the industry trying to protect its reputation and journalists trying to squeeze the most juicy bits of the report into brief news bulletins and articles. What the researchers have found, after thoroughly reviewing an accumulation of scientific literature that had been mounting in recent years, is that the consumption of red meat is “probably” carcinogenic to humans, based on limited evidence that the consumption of red meat causes cancer in humans, and strong mechanistic evidence supporting a carcinogenic effect. The association is mainly relevant to colorectal cancer, but there are also links to pancreatic cancer and prostate cancer.
Processed meat, on the other hand, is classified as conclusively carcinogenic to humans, based on sufficient evidence that the consumption of processed meat causes colorectal cancer. The group of 22 experts from 10 different countries who worked on the report also found an association with stomach cancer, but that evidence was not conclusive.
To put it statistically, the experts have concluded that each 50 gram portion of processed meat eaten daily increases the risk of colorectal cancer by 18%.
Researchers haven’t conclusively found exactly how processed meat, and possibly red meat, cause cells to become cancerous. The findings so far blame chemicals that are found in the meat, starting with heme, which is part of the red pigment in the blood. Heme is broken down in the gut to form N-nitroso compounds that can damage cells in the bowel lining. As a result of this, other cells in the bowel lining are forced to replicate in order to heal, and that replication can increase the risk of problems with the development of the extra cells’ DNA. That is the first stage in a sequence of events that can lead to cancer.
“For an individual, the risk of developing colorectal cancer because of their consumption of processed meat remains small, but this risk increases with the amount of meat consumed,” Head of the IARC Monographs Programme Dr Kurt Straif said. “In view of the large number of people who consume processed meat, the global impact on cancer incidence is of public health importance.”
The research also found that high-temperature cooking methods generate compounds that may contribute to carcinogenic risk, such as direct contact with a flame or hot surface. The suggestion is that hot barbecues or frying pans can cause an increased production of certain carcinogenic chemicals like polycyclic aromatic hydrocarbons and heterocyclic aromatic amines. However, there was not enough data available for the IARC Working Group to reach a solid conclusion on this theory yet. This is another area that is confusing consumers because the industry is understandably publicizing the lack of scientific evidence that currently exists, but scientists are saying, it is a risk, and it might very well be proven in the long-run.
Director of the IARC, Dr Christopher Wild, said the findings further support current public health recommendations to limit our intake of meat. “At the same time, red meat has nutritional value. Therefore, these results are important in enabling governments and international regulatory agencies to conduct risk assessments, in order to balance the risks and benefits of eating red meat and processed meat and to provide the best possible dietary recommendations.”
Smoking Versus Eating Red Meat
This is an interesting link that has been drawn during the aftermath of the research findings being released. Processed meat has now been classified as carcinogenic to humans (Group 1), which puts it in the same category as tobacco smoking and asbestos, which are also both classified as carcinogenic to humans (Group 1). Red meat, on the other hand, is considered potentially carcinogenic to humans (Group 2A). While processed meat has been placed in the same category as tobacco and asbestos, it does not mean it is as dangerous as them. The classification is based on the strength of scientific evidence, not the level of risk. To put it into perspective; smoking three cigarettes per day increases the risk of lung cancer by 600%, while eating 50 grams of processed meat per day increases the risk of colorectal cancer by 18%.
The most interesting thing, however, is how similar it is to the discussion on smoking several decades ago. Like the processed and red meat industries, tobacco stood to lose a lot when science was in its early stages of linking smoking to cancer, and the uproar from consumers was also very similar. That’s not to say the science of red and processed meat will necessarily go the same way, but studies are in their very early stages, and there is still a lot to be revealed, proven and disproven, such as the link with high-temperature cooking.
About 34,000 deaths from cancer per year worldwide can be attributed to diets high in processed meat, according to the most recent estimates by the Global Burden of Disease Project, an independent academic research organization. And while the link between red meat and cancer has not yet been established, estimates are that diets high in red meat could be responsible for 50,000 cancer deaths per year worldwide, if proven to be causal. That is compared to approximately 1 million cancer deaths worldwide each year caused by tobacco smoking.
What’s The Difference Between Red Meat And Processed Meat?
In simplistic terms, processed meat is generally considered unhealthy, while red meat is considered to be part of a healthy diet. Processed meat has been linked with a number of diseases and has been proven to possess harmful chemicals that would not be found naturally in unprocessed meat.
When meat has been preserved by curing, salting, smoking, drying or canning, it is called processed meat, and includes bacon, ham, sausages, hot dogs, salami and canned meat, to name a few. As the general consensus among the population over the last few decades has been that processed meat is unhealthy, it is usually consumed in high amounts by people with unhealthy lifestyle habits, rather than health-conscious people.
Red meat refers to muscle meat from mammals, including beef, pork, lamb, mutton, horse, veal and goat. It, on the other hand, has been a rather contentious subject, with evidence suggesting it can be harmful and evidence that it has health benefits. Humans have eaten meat throughout evolution, meaning our digestive systems are perfectly capable of handling it. However, even the unprocessed meat that humans eat today is extremely different to the free-roaming wild animal meat that our ancestors ate. If you’re buying a packet of steak from a supermarket in the US, then it most likely came from a steer born and raised in a factory farm, fed grain and probably pumped full of hormones and antibiotics. If you want natural red meat, it is important to look for grass-fed, certified organic cuts.
The Pros And Cons Of Eating Red Meat
PROS
Protein – This is where the science of red meat differs from processed meat. Where society accepts at large that processed meat should not be consumed for health benefits, red meat is known to be a great source of important nutrients. It is most commonly known for being rich in protein, which helps build muscles and bones. Eighty-five grams (3 ounces) of bottom-round steak (190 calories) provides 29 grams of protein, according to the US Department of Agriculture Nutrient Data Laboratory.
Iron – Red meat is also commonly associated with iron, a mineral that many teenage girls and pregnant women lack. The heme iron found in red meat is easily absorbed and is critical for binding and transporting the oxygen you breathe to the tissues throughout your body. It also plays a role in the enzymatic reactions during metabolism, detoxification, wound healing and growth, as well as improving the immune system, which is why an iron deficiency can affect a range of essential bodily functions.
Vitamins and Minerals – Red meat can be high in vitamin B12, B3 (Niacin), B6, zinc and selenium. Zinc helps during the production of new cells and supports the structure of proteins. It also supports the immune system and encourages neurological development. Because it is not stored in the body, it is important to get the little bit that you need every day through food. Selenium is an essential trace minimal that s necessary for immune system functionality. Deficiencies have been linked to mood swings and the risk of cardiovascular disease. B vitamins are extremely important during the metabolism process, especially in turning carbohydrates into energy.
Healthy Fats – Unprocessed red meat is full of healthy fats, especially from animals raised on grass. An Australian study found that beef from grass-fed animals contains up to 5 times the amount of Omega-3 as grain-fed animals. Oleic acid is a heart-healthy mono-unsaturated fat, famously found in olive oil, and it is also present in beef.
CONS
Climate change – There are other issues to take into account when eating meat of any kind, and one of them is the evidence that meat production is contributing to global warming. Agricultural activity worldwide, especially livestock production, is responsible for about a fifth of total greenhouse gas emissions. Scientists have concluded that lowering our consumption of meat will decrease the demand, and therefore decrease production, ultimately lessening greenhouse gas emissions.
Ethics – The other issue to consider is the ethical choice. Many people have turned away from eating meat and animal products in recent years in favor of plant-based foods. There has been a lot of publicity around animal intelligence, pain and suffering, alongside investigations that have uncovered cruelty within the meat industry around the world.
Diseases – Besides the recent evidence concluding that processed meat can cause cancer and that red meat most likely contributes to cancer, there are also a number of other diseases associated with the consumption of red meat. Research over the years has found that eating red meat, particularly in large amounts, may shorten your lifespan and increase the risk of diabetes and cardiovascular disease.
So, Should I Eat Red Meat?
This is the question that everyone wants answered and the problem is, you can read two different news stories in one day that will say the opposite. We already know the answer to the processed meat question. No, you shouldn’t eat processed meat if you want to eat cleanly, and if you do eat it, it should be on an extremely rare occasion in extremely small amounts.
The jury is still out on red meat, however. On the one hand, scientists say it probably contributes to cancer, even though they haven’t yet been able to conclude that absolutely. On the other hand, it is one of the best sources of protein available and has some very beneficial nutrients and important vitamins and minerals.
Whether you choose to eat red meat or not, the biggest issue in the western world is the over-consumption of meat in general. Many people still believe meat needs to be the feature point in a meal and the vegetables and carbohydrates, a necessary side accompaniment. But that is the wrong way to think about meals. They should be considered as a whole, and meat should be eaten in far smaller percentages than it currently is on average. Vegetables and carbohydrates should make up the bulk of your meal, with meat being a maximum of 20% of it. On top of that, it should not be featured in every meal. There are plenty of other sources to get iron and protein from, so some days should be vegetarian or vegan days, and some days can include a meal that features meat in it.
The Bottom Line
Processed meat has been linked to cancer. That is a fact. The industry and people who don’t want to give it up can spin it in different ways, but that is the current science on it. Red meat has not been so strongly linked to cancer. There are robust suggestions that it potentially poses the risk, and the general consensus amongst scientists is that it will probably be proven down the track, but in terms of modern science, there is not a solid conclusion as of the year 2015.
So, does processed meat increase the risk of cancer? Yes. Does red meat? Probably.