Tag Archives: red meat

Why is pork bad for you — a look at what the science says

Although in small quantities of under 70 grams (2.5 ounces) / day, red meat is not as harmful to your health, consumption of pork is associated with a significant risk of several chronic conditions including diabetes, cardiovascular disease, and several types of cancer.

“I would never recommend eating animal products, and certainly not pork,” says Dana Hunnes, assistant professor at the UCLA Fielding School of Public Health.

The main (but not the only) reason why pork is bad for you is its high content of saturated fats and cholesterol. However, as is often the case with nutrition, the scientific studies are not always clear-cut, and dietary recommendations tend to be laxer than existing evidence.

We eat too much pork

Pigs were domesticated in Mesopotamia, around 15,000 years ago. But up until the 20th century, consumption of pork was relatively low, and often restricted to the autumn-winter part of the year.

In the 20th century, mankind rethought its animal consumption, and industrial farming took over. The world now produces 4 times more meat than 50 years ago — which in 2013, meant 320 million tons of meat. Over 80 billion animals are slaughtered each year for meat, with pig meat being the most popular type of meat globally (although poultry is increasing most rapidly).

The average American consumes 124 kilograms of meat every year, and around 24 of those are pig. Pork (the “food” name of pigs) is consumed in a number of ways, from sausages and bacon to fresh meat and lard.

Image credits: Our World in Data.

Pork consumption in the US has remained relatively stable for much of the past century (although chicken, turkey, and beef have increased compared to the early 1900s). But this doesn’t necessarily mean good news.

Virtually all dietary guidelines recommend no more than 500 grams (1.1 pounds) of red meat a week — not just pork. Meanwhile, Americans consume double that, and the numbers keep growing.

It’s not just Americans (although the US is near the top of the list for per capita red meat consumption) — as the world is becoming more affluent, it is consuming more red meat, and pork is a staple in many parts of the world.

Despite some claims from the industry, pork is undoubtedly red meat. In particular, one advertising campaign from the U.S. National Pork Board labeled pork as “the other white meat”. The campaign was highly successful, and at some point, 87% of consumers identified pork with the slogan, although the USDA never considered pork to be anything other than red meat.

“Pork is considered a red meat, and it is high levels of saturated fat, and all of the other animal protein compounds that are deleterious to health. Pork is not a “white meat”, and even if it were, white meat has also been demonstrated to be deleterious to health,” Hunnes told ZME Science.

Is pork bad for you?

In 2012, a large study on over 100,000 individuals found strong evidence that consumption of red meat is linked to a shorter and less healthy life. The evidence was strong, although pork wasn’t analyzed in particular — this is often the case with such studies, they classify all red meat together.

“This study provides clear evidence that regular consumption of red meat, especially processed meat, contributes substantially to premature death,” according to Dr. Frank Hu, one of the senior scientists involved in the study and a professor of nutrition at the Harvard School of Public Health.

It was by no means an isolated study. Studies have highlighted the health risks associated with pork consumption for decades. Sometimes, it’s not always obvious problems — for instance, a 1985 study finding a correlation between pork consumption and cirrhosis. But most of the time, the same health problems pop up. Despite the fact that pork can be a source of nutrients such as protein and iron, it is associated with a number of health problems.

Pork consumption and cancer

In 2015, the International Agency for Research on Cancer concluded that red meat is probably carcinogenic to humans. Several types of cancer have been linked to pork. For instance, a 2011 analysis found that for each additional 100 grams of red meat (either pork or beef) per day, the risk of colorectal cancer increases by 17%. Correlations were also observed for pancreatic and prostate cancer, although the associations were not as strong.

“High intake of red and processed meat is associated with significant increased risk of colorectal, colon and rectal cancers,” the study concluded.

Even moderate intake of pork can increase the cancer risk, another study found. The study, carried out in 2019, found that even red meat consumption in accordance with existing guidelines leads to an increased bowel cancer risk: 20% with each extra slice of ham or rasher of bacon per day. This is particularly significant because it shows that the risk has remained significant even as people’s diets may have changed over the years.

Pork belly. Image credits: Rainer Zenz.

It’s worth noting that all these are big studies — and there’s more. A 2013 meta-analysis (a study of studies) found that gastric cancer risk also increases with red meat consumption, although the authors called for more research to clarify this connection.

A 2016 literature review found that for 100g or more per day of red meat, the risk breast cancer increases by 11%, 17% for colorectal cancer, and 19% for prostate cancer.

Meanwhile, a 2017 review found numerous potential carcinogens in red meat products, including polycyclic aromatic hydrocarbons, and heterocyclic amines

“Red meat products, especially those that have been processed, have a wide variety of carcinogenic molecules known to increase the risk of colorectal cancer,” the study concluded.

It should be noted that this is an increase in relative risk. Let’s take an example.

Let’s say the cancer risk is 10%, and pork consumption causes a 17% increase in the total cancer risk. The net increase in risk is 17% of 10% — so in total, it’s a 1.7% increase that takes the total risk from 10 to 11.7%.

Some use this to claim that the disease risk from red meat is exaggerated. At the end of the day, we all judge risk in our own way, and one may consider the extra risk acceptable — but even a 1% change is huge considering how common these diseases are.

The exact risk is hard to establish, but overall, pork consumption seems to be linked with higher cancer risk. There is “sufficient evidence” to draw a link between the consumption of processed meat products and cancer, WHO experts also conclude.

Pork consumption and obesity

It’s no secret that the world (and especially the developed world) is facing an obesity crisis. Decades ago, the culprit was considered to be fat, whereas in more recent years, sugar has also emerged as a major issue. However, according to a recent study, meat is also to blame.

“In the analysis of obesity prevalence across 170 countries, we have found that sugar availability in a nation explains 50% of obesity variation while meat availability another 50%. After correcting for differences in nations’ wealth (Gross Domestic Product), calorie consumption, levels of urbanization and of physical inactivity, which are all major contributors to obesity, sugar availability remained an important factor, contributing independently 13%, while meat contributed another 13% to obesity,” said Professor Maciej Henneberg, head of the Biological Anthropology and Comparative Anatomy Research Unit, and one of the study authors.

Again, the effect of individual meats was not calculated, but overall, high meat availability was found to be correlated with obesity. It’s also worth noting that it’s not necessarily the fat, but also the protein in the meat that contributes to obesity.

According to another 2014 review of studies covering a combined total over 1 million participants, “red and processed meat intake is directly associated with risk of obesity, and higher BMI.”

The key to understanding these nutritional studies is to look at the big picture. You will always find differences between individual studies, and you can find studies that support varying viewpoints.

If you want to have a better understanding of this process, it’s best to look at large-scale studies and reviews of studies.

The fact that many diet-and-disease studies lump pork together with other types of red meat also dilutes the association related to pork alone.

According to the Global Burden of Disease study 4.7 million people died prematurely in 2017 as a result of obesity. Obesity is one of the most important health risk factors. According to recent estimates

Pork consumption and the link to diabetes and cardiovascular disease

This is where things are not as clear as before. Because red meat consumption is associated with increased weight, and increased weight is associated with diabetes and cardiovascular disease, it’s doubly difficult to assess which risks are caused directly by meat, and which by increased weight. This is why studies in this regard are often inconclusive and hard to interpret.

Even so, the prevailing evidence seems to show negative effects of red meat consumption.

A 2011 study on over 100,000 participants found that “red meat consumption, particularly processed red meat, is associated with an increased risk of type 2 diabetes.” Substituting one serving of red meat per day with nuts, low-fat dairy and whole grains reduces the risk of type 2 diabetes by up to 35%. Another study, one year earlier, concluded that a “reduction of the consumption of processed meat may help prevent the global epidemic of type 2 diabetes”.

A review of almost half a million people found a positive link between red meat consumption and cardiovascular disease and overall mortality. Eating red meat daily triples the levels of a heart disease-related chemical called TMAO.

“These findings reinforce current dietary recommendations that encourage all ages to follow a heart-healthy eating plan that limits red meat,” says nutrition researcher Dr. Charlotte Pratt, the NHLBI project officer for the study. “This means eating a variety of foods, including more vegetables, fruits, whole grains, low-fat dairy foods, and plant-based protein sources such as beans and peas.”

Another recent study has found that eating two servings of red meat per week was linked to a 7% higher risk of heart and circulatory diseases, compared to eating none at all (again, this is relative risk).

However, another study concluded that eating meat within the recommended quantity does not increase cardiovascular risk, and recent studies have called for more studies on this issue.

A part of the reason why nutritional studies are so hard to reconcile is that they often rely on self-reported questionnaires. Humans are notoriously unreliable when it comes to self-reporting and often tend to distort the data.

This is why it’s important to look at results from multiple angles, and when possible, also try to find the mechanism producing the observed effect.

Another important aspect is how the meat is prepared: is it processed, and if yes, how? Is it cooked at high temperatures? All this can matter. As a rule of thumb, the more it is processed and cooked, the worse it is. This is particularly concerning since pork is often consumed in processed form (in products such as bacon or sausages), which seem to have an even higher health risk.

Other health risks associated with pork consumption: liver disease, MS, yersinia

Some of the health issues associated with pork consumption tend to fly under the radar.

For instance, the link between pork and multiple sclerosis (MS) is known at least since the 1980s, and has been demonstrated across dozens of countries. The link has been supported by multiple studies carried in various environments. It’s more than just an observation: between 2007 and 2009, a cluster of 24 pork plant workers fell mysteriously ill with a disease that triggers MS-like symptoms — a problem which was ultimately traced back to pork.

Remember the 1985 cirrhosis study we mentioned at the start of the article? Surprisingly, pork can also cause liver disease, including cirrhosis and liver cancer. Alcohol is of course a main driver here, but pig meat has been repeatedly proven to play a role in both liver cancer and cirrhosis.

Yersinia is another potential risk factor that is often overlooked. In pork that isn’t properly cooked, the Yersinia bacteria can creep in, causing severe symptoms and even contributing to mortality. In the US alone, yersinia kills 35 people and causes 117,000 cases of food poisoning each year. Its main point of access inside the human body? You’ve guessed it — pork. The problem can be averted by properly cooking the meat.

Can pork ever be good for you?

Example of nutritional value of 100 gram serving of pork. Values may vary substantially based on the type of meat and how it is prepared.

Every once in a while, you end up seeing a “pork isn’t bad for you” study picked up by the media. Recently, one such study published in late 2019 made all the rounds. “Red meat is back on the menu” and “Stop worrying about red meat” were just some of the headlines flown around, validating what meat lovers all around the world wanted to hear. But there’s a problem — several, actually.

This was just one study, the authors themselves admitted low-quality evidence, and the study was called into question in more ways than one (see our detailed analysis of that study here).

A Professor of Medicine and Human Nutrition at University of Otago, New Zealand, summed up the general feeling among scientists:

“In my opinion, the weak recommendation based on low-certainty evidence that adults continue current consumption of unprocessed red meat and processed meat is potentially unhelpful and could be misleading.”

This doesn’t mean that the study is meaningless or that we should immediately disregard conflicting evidence — but neither should we overturn decades of research because a conflicting study came out. This just means that we shouldn’t jump on the next study that gets picked up by the media. Instead, looking at multiple, large studies can offer a much more accurate image.

It can be daunting to look through studies when all you want is to know whether bacon is alright, so if you want to boil it down to a simple tidbit, it’s hard to see pork as part of a healthy diet.

“All animal proteins, exclusive of what animal they come from, can be harmful to health, especially if and when they are processed. So I would never recommend eating animal products, and certainly not pork,” says Hunnes.

This being said, if your diet is low in salts, saturated fats and you have an active lifestyle, you can incorporate low amounts of lean, preferably unprocessed pork into your diet, and will still have a relatively low risk of developing chronic diseases.

There are many things we don’t fully understand about nutrition, but what we do know is that the total matters more than the sum of the parts. Some things are healthier than others, and it’s important to be careful with all aspects of your lifestyle.

However as Havard researchers have pointed out, even the dietary guidelines sometimes don’t take into consideration the risks that their very own analyses highlight.

But don’t you need red meat for protein?

As mentioned, pork can contain large amounts of protein, but the idea that you need to eat red meat to get your protein is a myth.

“We need nutrients, and we need amino acids that come from protein, but neither of these do we need from animal proteins,” Hunne explains.

Replacing red meat with plant protein has been found to increase longevity and improve overall health in a number of studies. While people who don’t eat much meat (or don’t eat meat at all) need to pay some attention to complementing their protein and vitamin intake, diets focused on plant rather than animal protein tend to be associated with better health outcomes.

Plant-based protein is associated with better health in several studies.

In 2006, a study compared plant with animal protein, concluding that “with a proper combination of sources, vegetable proteins may provide similar benefits as protein from animal sources.”

Results of a 2016 meta-analysis found that plant-based protein is associated with a lower risk of disease of all-cause mortality, and cardiovascular problems — a link that was especially prevalent for people who have at least one health risk factor.

“Substitution of plant protein for animal protein, especially that from processed red meat, was associated with lower mortality, suggesting the importance of protein source.”

The bottom line

Consumption of meat, in any quantity, can be detrimental to your health in a number of ways, and generally speaking, the more you eat, the more you increase your risk.

Not all pork is made equal. Uncooked meat can carry pathogens, while processed meat tends to be worse. Meat that is high in saturated fats and trans fats causes the greatest risk to health.

Multiple conditions have been associated with pork consumption, including but not limited to diabetes, MS, cardiovascular disease, obesity, cirrhosis, and multiple types of cancer. The exact nature of this risk is still a matter of active research, but if you want to be on the safe side, no amount of pork is safe. If you just can’t give it up, the common recommendation is to not go over 500 g (1.1 pounds) per week and stick to lean, unprocessed meat.

Substituting red meat protein with plant protein is linked to a longer, healthier life, with multiple studies backing this up. Reducing pork consumption can also have a positive environmental impact, reducing the greenhouse gas emissions and water consumption associated with our food. Ethically, slaughtering billions of animals every year (especially animals as — or even more — intelligent than dogs) is not the right thing to do.

Oh, and there’s another reason why avoiding pork might be wise, Hunnes notes.

“In the past couple of decades, a couple of disease epidemics (swine flus) have emerged from pigs. Just another reason not to raise animals in confinement.

In short, I do not recommend eating pork. Under any circumstances,” she concludes.

Credit: Pixabay.

Replacing red meat with a plant-based diet increases longevity

People who replaced red meat in their diet with nuts, seeds, fish, vegetables and whole grains, experienced a more than 10% reduction in their risk of mortality. The biggest gains in longevity were experienced by those who ate considerable amounts of processed red meat and then switched to a plant-based diet.

Credit: Pixabay.

Credit: Pixabay.

In their new study, nutritionists at the Harvard T.H. Chan School of Public Health tracked the diets and health outcomes of more than 80,000 for several decades. During the study’s timeframe, 14,019 deaths were recorded.

The researchers analyzed the association of changes in red meat consumption over eight years with mortality risk during the subsequent eight years. The findings revealed a strong association between shifting away from red meat and leading a longer, healthier life.

“An increase in total red meat consumption of at least half a serving per day was associated with a 10% higher mortality risk. For processed and unprocessed red meat consumption, an increase of at least half a serving per day was associated with a 13% higher mortality risk,” the authors wrote in the British Medical Journal.

Although red meat consumption in the United States had declined in recent years, it’s still more than twice the global average. Previously, studies have linked high red meat consumption — particularly processed red meat (i.e. hot dogs, bacon, sausages) — with an increased risk of type 2 diabetes, cardiovascular disease, and certain types of cancer. Scientists think that these adverse health outcomes may be due to red meat and processed red meat components such as saturated fats, sodium, preservatives, and potential carcinogens like polycyclic aromatic hydrocarbons.

Even a moderate amount of red meat can be dangerous. A recent study, which followed half a million men and women who signed up for the UK Biobank research project, found that the risk of bowel cancer for people who eat 76g of processed red meat a day (the equivalent of 3 rashers of bacon) is 20% higher compared with those who averaged 21g a day. That’s equivalent to an approximately 10% increase in risk per daily rasher of bacon.

While there are a lot of studies showing that red meat consumption is strongly associated with increased mortality risk, this study is different. It’s one of the few that tracked what happened when people switched away from red meat. According to the researcher’s estimate, replacing red and processed meats with nuts, seeds, veggies, whole grains, and alternative proteins (fish, up to an egg a day, etc) leads to a 10% average reduction in the risk of mortality.

Although this is an observational study, which cannot establish cause and effect, the findings agree with a growing body of literature on the adverse effects of red meat.

“Our analysis provides further evidence to support the replacement of red and processed meat consumption with healthy alternative food choices,” the authors concluded.

Even moderate intake of red meat substantially increases risk of bowel cancer

Even if you follow the dietary guidelines for red meat, you’re still at an increased risk of cancer, a new study concludes.

Want to reduce your risk of cancer? Eat less red meat, a new study suggests.

A five-year study followed half a million men and women who have signed up for the UK Biobank research project. They found that the risk of bowel cancer for people who eat 76g of processed red meat a day (the equivalent of 3 rashers of bacon) have a 20% increased risk of bowel cancer compared with those who averaged 21g a day. There’s an approximately 10% increase in risk per daily rasher of bacon.

Researchers also report that the risk increases by 19% with each thick slice of roast beef or the edible part of a lamb cutlet (about 50g).

In the UK, the dietary guidelines suggest a consumption lower than 70g per day — which is still enough to put people at risk. In the US, the Dietary Reference Intake is 0.8 grams of protein per kilogram of body weight, or 0.36 grams per pound, which amounts to approximately 56 grams per day for the average sedentary man and 46 grams per day for the average sedentary woman.

There were a few factors affecting the increased risk. Alcohol drinkers had an 8% higher risk per for every 10 g per day. Meanwhile, people who ate more fibers enjoyed a protective effect.

It’s important to put this into perspective. The 10% increase in risk per rasher of bacon is relative, not absolute. It’s estimated that by 2035, the incidence rate for bowel cancer will be 74 cases per 100,000 people — so for the absolute average person, the risk is 0.074%. For every rasher of bacon a day, your bowel cancer risk increases relatively by 10%, and absolutely by 0.0074% — which doesn’t seem nearly as damning, although you should keep in mind that the risk is also exacerbated by other factors such as alcohol, sedentary lifestyle, and insufficient consumption of dietary fiber. In this particular study, the absolute risk was found to increase by 0.2%.

At the end of the day, the choice is yours. It’s not the be-all-end-all of good health, but it is significant. Bowel cancer is not the only risk associated with red meat, which has been found to also increase the risk of many other health conditions and to reduce overall lifespan. In addition, red meat is very taxing on the environment.

The study has been published in the International Journal of Epidemiology.

Eating a lot of animal protein probably means you’ll have a shorter life

Finnish researchers found that a diet rich in animal protein, particularly red meat, increases a person’s risk of death compared to individuals who include plant-based protein in their diet.

Credit: Pixabay.

The study was performed by a team of researchers at the University of Eastern Finland, who analyzed the data from the Kuopio Ischaemic Heart Disease Risk Factor Study (KIHD). The study included the diets of about 2,600 Finnish men aged between 42 and 60 at the start of the study in 1984. Researchers performed follow-ups with the participants up 20 years after the study’s onset.

The results suggest that men whose primary source of protein was animal-based had a 23% higher risk of death compared to men who ate a balanced ratio of animal and plant-based protein. Specifically, men who ate more than 200 grams of meat per day had a 23% higher risk of premature death during the follow-up than men whose meat intake was less than 100 grams per day. As a caveat, the study only included Finnish men who primarily consumed red meat (i.e. pork, beef), which is associated with more health problems than white meat (i.e. chicken).

Previously, researchers found that red meat (and processed meats) causes cancer, common inflammatory bowel condition, and raises the risk of premature death.

High protein intake, whether animal- or plant-based, was associated with a greater risk of death in individuals who had type 2 diabetes, cardiovascular disease or cancer at the onset of the study. High protein intake did not seem to be associated with an increase in the risk of death for healthy people.

“However, these findings should not be generalized to older people who are at a greater risk of malnutrition and whose intake of protein often remains below the recommended amount,” Ph.D. Student Heli Virtanen from the University of Eastern Finland points out.

The findings appeared in the American Journal of Clinical Nutrition. In the future, researchers would like to gain a better understanding of the relationship between different sources of protein and their health effects.

Processed meats DO causes cancer, red meat probably does too

An eagerly awaited report from the World Health Organization (WHO) states that processed meats such as bacon and sausages cause cancer, and red meat likely does so too.

Photo by Benjamin Faust.

Photo by Benjamin Faust.

The France-based International Agency for Research on Cancer (IARC), part of the WHO, put processed meats on the top of their “things that cause cancer list”, grouping them alongside tobacco, asbestos and diesel fumes, for which there is “sufficient evidence” of cancer links.

“For an individual, the risk of developing colorectal (bowel) cancer because of their consumption of processed meat remains small, but this risk increases with the amount of meat consumed,” Dr Kurt Straif of the IARC said in a statement.

Along the years, there have been many studies that linked processed and red meats with cancer (especially bowel cancer), but there were always some doubts floating about. Now, the 22-member panel analyzed animal experiments, studies of human diet and health, and cell mechanisms that could lead from these meats to cancer.

“These findings further support current public health recommendations to limit intake of meat,” Dr. Christopher Wild, who directs IARC, said in a statement.

The decision wasn’t unanimous though, and a “probably” still crept in to the report. Many studies show the links, both in populations of people and in tests that show how eating these foods can cause cancer, the International Agency for Research on Cancer (IARC) said in its report, released in the Lancet medical journal.

This is WILL give you cancer. Photo by Niklas Rhose.

This could give you cancer. Photo by Niklas Rhose.

Most reports on the links between meat and cancer have been softened with some element of doubt, but the IARC uses clear and direct language in saying processed meat causes cancer. There are no phrases such as “may cause” in the report.

“Overall, the Working Group classified consumption of processed meat as ‘carcinogenic to humans’ on the basis of sufficient evidence for colorectal cancer,” the report reads. “Additionally, a positive association with the consumption of processed meat was found for stomach cancer. The Working Group classified consumption of red meat as ‘probably carcinogenic to humans’,” it added.

In case you’re wondering just what processed meat is, the panel also defines it:

“Processed meat refers to meat that has been transformed through salting, curing, fermentation, smoking, or other processes to enhance flavor or improve preservation. Most processed meats contain pork or beef, but might also contain other red meats, poultry, offal (eg, liver), or meat byproducts such as blood.”

This of course, isn’t exactly news – it’s only a meta-analysis, of things we’ve already known, but it’s a way of the world’s leading health organization to draw its line and tell people to stop eating these foods. But they even put some figures on it:

“The experts concluded that each 50 gram portion of processed meat eaten daily increases the risk of colorectal cancer by 18 percent,” the IARC said. “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,” said IARC’s Dr. Kurt Straif.

They also mentioned red meat, which was also documented to favor the development of cancer. Red meat is defined as follows:

“Red meat refers to unprocessed mammalian muscle meat—for example, beef, veal, pork, lamb, mutton, horse, or goat meat—including minced or frozen meat; it is usually consumed cooked,” the IARC said in its report.

Red meat was included in a lower category, which means that while there is evidence for it causing cancer, there is still quite a lot of room for debate. But while processed meat seems to be decidedly bad for your health, not everybody is convinced about red meat.

The $95 billion U.S. beef industry has been preparing a retaliation for months, and they’ve been rallying numerous scientists to their cause – even some unafililiated with the meat industry.

“We simply don’t think the evidence support any causal link between any red meat and any type of cancer,” said Shalene McNeill, executive director of human nutrition at the National Cattlemen’s Beef Association.

For now, the takeaway seems to be this: you need to stop eating processed meat. They have a number of damaging effects, including elevating stroke risk, raising cholesterol and, of course – cancer. If you absolutely can’t give it up, then reduce it. Quantity does matter, and less is, while not ideal, better than more. The same goes for red meat – if you must have it, don’t have it every day. It’s not sustainable, it’s bad for the animals, and it’s bad for you.

We’re getting to a point where science is starting to understand what’s good for us and what’s not. Let’s make the science count, shall we?