Health Risks of Eating Red Meat: Facts or Scares?
Red meat is one of the most controversial foods.
There have been news reports based on scientific studies saying eating red meat will clog your arteries and dramatically increase your risks of getting heart disease and cancer.
There has also been news also based on scientific studies saying that red meat is nutrient dense and meat from pasture raised and free roaming animals are a superfood of sorts.
So which is true?
In this article, what I’m going to do is to look at all the scientific evidence available, and give you the real deal behind the purported health risks of eating red meat.
Does Red Meat increase Risk of Heart Disease and Diabetes?
The idea that red meat causes heart disease stems from the outdated and mistaken notion that red meat contains saturated fat and cholesterol which supposedly increase heart disease risk.
If this was true, then the Maasai tribes in Kenya and Tanzania would have all died of heart disease and be extinct long ago because their traditional diet comprise mainly meat, milk and blood. In fact, their daily consumption of cholesterol ranges from about 600 mg to 2,000 mg which is way past the American Heart Association’s daily recommendation of no more than 300 mg.
Well we all know that they didn’t….
So what about the studies that experts quote to claim that red meat is associated with heart disease you may ask. Well, such studies are all observational studies which just mean that there’s some correlation but that’s just about it. Observational studies DO NOT PROVE causation like randomized studies because correlation DOES NOT EQUAL causation.
I’ve already dispelled the myths about saturated fat, cholesterol and heart disease in an earlier blogpost, but I’ll show the evidence again for those who are reading my blog for the first time.
First of all, 75% of the cholesterol in our bodies is produced by the liver with the remaining 25% being supplied by food sources. But this doesn’t mean that if we eat lots of high fat and cholesterol laden foods we’ll get elevated cholesterol levels in our blood because in such a situation, the liver simply produces less cholesterol.
Moreover when we eat foods that are high in cholesterol like eggs and organ meat, they not only increase HDL that lowers heart disease risk they also change the profile of our LDL from the harmful small particle subtype to the harmless large particle subtype. This is also seen when we eat foods high in saturated fats like ground beef and lamb.
That having said, there’s a rough 30% in any population (termed hyper-responders) whose cholesterol levels DO get elevated when they eat high fat and cholesterol laden foods. But there’s really nothing to worry about even if you’re a hyper-responder because the slight spike is mostly due to the increase in HDL. And although LDL also goes up as well, it also changes to the harmless large particle subtype.
Okay, now that we know that eating saturated fats and cholesterol laden foods DO NOT negatively impact lipid profiles then will red meat increase heart disease and diabetes risk?
The skyrocketing rates of diabetes, heart disease and other chronic diseases in the developed and developing world are pretty recent phenomena which only came about from the 60s onwards which is about 50 years ago.
Mankind, however, has been eating red meat for probably millions of years and yet those that are for this line of argument are blaming an old food for a new problem! This doesn’t make any sense does it?
Let’s take a look at what science tells us about this….
In this huge 2010 mega analysis of over 20 studies involving over 1.2 million people, the researchers found no link at all between meat consumption and diabetes or heart disease.
However, what the researchers found was that, “processed meat intake was associated with 42% higher risk of CHD (coronary heart disease) and 19% higher risk of diabetes.”
Another 6-week controlled study by the Texas A & M University found that frequent beef consumption had a neutral impact on heart disease risk factors.
Yet another randomized controlled Danish study found that red meat consumption resulted in an 8% increase in HDL. So as far as this study goes, not only did the researchers not find eating meat increasing heart disease risk, they also found that it had a positive impact on heart health!
However, one mega review of observational studies found that eating half a serving of red meat every day increased the risk of developing diabetes by 30%.
Now what this mega review and analysis doesn’t give is information relating to other foods that the incumbents ate which could have attributed to the increased diabetes risk e.g. high consumption of refined carbs and sugar will definitely increase diabetes risk.
My conjecture is that it could be that it’s the highly refined carbs and sugar laden foods that were eaten together with the meat that drove diabetes and not necessarily the meat.
In fact, people on very low carb high fat ketogenic diets experience drastic reductions in their blood sugars quite quickly and such low carb diets invariably include red meat in the meal plans.
But the same cannot be said of processed meat, which incidentally, is almost always included into studies regarding red meat – probably that’s why that’s where the confusion lies.
In this Swiss study by the University of Zurich of over 400,000 individuals, the researchers estimated that “3.3% (95% CI 1.5% to 5.0%) of deaths could be prevented if all participants had a processed meat consumption of less than 20 g/day. Significant associations with processed meat intake were observed for cardiovascular diseases, cancer, and ‘other causes of death’.”
Their conclusion was that, “The results of our analysis support a moderate positive association between processed meat consumption and mortality, in particular due to cardiovascular diseases, but also to cancer.”
Another mega analysis by Harvard that looked at 20 studies involving over 1.2 million people found that “processed meat intake was associated with 42% higher risk of CHD (coronary heart disease) and 19% higher risk of diabetes mellitus.” The researchers concluded that “consumption of processed meats, but not red meats, is associated with higher incidence of CHD and diabetes mellitus.”
In yet another mega study of over 91,000 women that went on for 8 years, researchers at Harvard found that those consuming processed meat 5 times a week or more had a whopping 95% higher risk of developing Type 2 diabetes; they concluded that, “frequent consumption of bacon, hot dogs, and sausage was each associated with an increased risk of diabetes.”
Does Eating Red Meat Cause Cancer?
In October 2015, the World Health Organization issued a warning that processed meat causes cancer and that red meat “probably” causes cancer.
That sent shockwaves around the world especially in the paleo and low carb/keto diet communities where red meat was and still is promoted as a natural whole food.
We know that processed meat causes cancer because, “meat processing, such as curing and smoking, can result in formation of carcinogenic chemicals, including N-nitroso-compounds (NOC) and polycyclic aromatic hydrocarbons (PAH)” as stated in the WHO report which was published in the Lancet.
The report further stated, “Cooking improves the digestibility and palatability of meat, but can also produce known or suspected carcinogens, including heterocyclic aromatic amines (HAA) and PAH. High-temperature cooking by pan-frying, grilling, or barbecuing generally produces the highest amounts of these chemicals.”
So by inference, it means that as long as the red meat is unprocessed and not cooked in the high temperatures, then it is safe to consume.
This indeed appears to be the case because this study from the University of Hawaii found that folks who prefer to have their steaks well done are 8.8 times more likely to get colorectal cancer than those who prefer to have their meat medium or rare.
Another 10-year study by the University of Minnesota which involved over 62,000 people found that meat cooked in high temperatures increased the risk of pancreatic cancer.
Then a review of the different studies show that well done meat, and in this case, both processed and unprocessed meat increased the risk of breast, colorectal and prostate cancers.
So the question is: why does cooking red meat in high temperatures appear to increase cancer risk? Well it appears that the high temperatures result in the formation of toxic carcinogenic substances that increase cancer risk.
Let’s look at the various high temperature cooking methods and examine which are the most harmful ones that increase cancer risk.
Grilling, Broiling and Roasting
Grilling involves having the source of heat directly below your food e.g. in a BBQ or an open grill. On the other hand, the heat source in broiling is directly above such as the broiler in the oven. Roasting is slightly different: it uses a more indirect and diffused heat e.g. in an oven and is suitable for slower cooking of meat in a larger, whole piece.
Grilling, broiling and roasting involve temperatures that are pretty high, usually between 190⁰ C and 288⁰ C (375⁰ F and 550⁰ F).
When red meat is cooked at high temperatures, the fat melts and drips onto the grill or the oven pan in the case of broiling. This creates toxic carcinogenic compounds known as polycyclic aromatic hydrocarbons or PAHs which vaporize and seep into the meat.
But there’s a good new because once you remove the drippings, the levels of PAH can be reduced by as much as 89%. The researchers in this Korean study found that the “4 PAHs were reduced 48-89% with dripping removed and 41-74% with the smoke removal treatment in grilled pork and beef meats than conventional grilling.”
Grilling, broiling, roasting and other high temperature cooking methods also produce harmful advanced glycation end products or AGEs which are proteins and fats that form in a chemical reaction when exposed to sugars – this process is called glycation.
One study from the Kansas State University found that broiled beef contained the highest level of AGEs compared to other cooking methods.
Pan Frying, Stir Frying and Deep Frying
Pan frying, stir frying and deep frying are other high temperature cooking methods that increase cancer risk because such cooking methods produce heterocyclic amines (HAs) which are carcinogens.
A 2005 study by the University of Hong Kong showed that the increased proliferation of lung cancer in Asian women was directly linked to the toxic carcinogenic vapors inhaled during stir frying, a hallmark of East and South East Asian cooking.
This 1994 2-week study by the National Cancer Institute of 66 individuals found that pan fried meat had high amounts of HAs; in contrast meat cooked in low temperatures had negligible and undetectable amounts of HAs.
This 24-year Finnish mega study involving over 9,000 men and women found that pan fried meat was positively linked to cancers of the breast, endometrium and ovary; but the researchers also found that the links to pancreatic and nervous system cancers were insignificant.
Another population based study by the National Cancer Institute found that, “consumption of red meat, especially fried and/or well-done red meat, was associated with increased risk of lung cancer.”
Deep frying meat appears to be the most harmful of all the high temperature cooking methods because it produces the most toxic byproducts such as AGEs, aldehydes and HAs. Moreover the typical oils like commercial vegetable and seed oils e.g. corn oil, canola oil, soybean oil etc. used in deep frying also contribute to increased risks of cancer and heart disease. I’ve written an in-depth article on the best oils to use for cooking.
This study from the Fred Hutchinson Cancer Research Center in Washington found that regular consumption of deep fried foods increased prostate cancer risk. It was reported in Medical News Today: the researchers found that “men who ate one or more of French fries, fried chicken, fried fish and/or doughnuts at least once a week were at an increased risk of prostate cancer as compared to men who said they ate such foods less than once a month. Those who ate one or more of these foods at least weekly had an increased risk of prostate cancer that ranged from 30 to 37 percent.”
Okay, so now that we know such high temperature cooking methods have a negative impact on our health, what are the more healthy ways to cook red meat?
Steaming, Poaching, Simmering and Stewing
Steaming is one of the healthiest ways to cook your meats. Very little oil is used and it works by continuously boiling the water so that the steam cooks your meat on a plate on a steamer or steaming rack above the boiling water on your saucepan or wok in the case of Asian cooking.
The highest temperature is around 100°C or 212°F, with most of the nutrients of the meat are preserved with undetectable or very little of the formation of toxic carcinogenic substances found in high temperature cooking. It is much more prevalent in Asian cultures and cuisines than in Western ones.
Poaching is another healthier low temperature to cook your meat although it’s best for delicate foods like eggs, fish and white meat. The temperatures for poaching is lower than that of steaming: around 60⁰ to 82⁰C or 140⁰ to 180⁰F
Another low temperature cooking method is simmering which is getting the cooking liquid, be it broth, soup or water to a temperature just under boiling point which is between 85⁰ C and 93 C (185⁰ to 200⁰ F).
Stewing is slow cooking the ingredients usually meat, fish or seafood, vegetables and roots/tubers in gravy so that allowing the flavors to mingle and soak into the ingredients. Typically the stewing temperatures are between 71⁰ C and 82⁰ C (160⁰ F to 180⁰ F).
So Is Red Meat Safe?
Going by what we saw in the studies, eating red meat does seem to carry an increased risk of cancer when it is cooked in high temperatures.
However, that being said, the World Health Organization also admitted that “there were not enough data for the IARC Working Group to reach a conclusion about whether the way meat is cooked affects the risk of cancer.”
Also I need to remind everyone that most of these mega population based studies are observational studies and they just point to correlation which doesn’t equate to causation.
In the final analysis, my personal suggestion is to cook your red meat in lower temperatures to mitigate the risks. There’s no need to completely avoid red meat unless cancer runs in your family. If you’re still worried then just cut down the frequency of eating red meat. As for processed meat, it seems pretty clear that the risks are even higher so limiting your intake or even avoiding it would be a wise decision.