Red Meat and Cancer – What’s the Risk?

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A recent meta-study from the International Agency for Research on Cancer (IARC) tries to answer the question if consuming red and processed meat increases the risk of cancer.

I contacted the World Health Organization (WHO) and the IARC to find out what the new study means for the Paleo diet and how real the risk is. Specifically, I was looking for answers to the following questions:

  • How can red meat cause cancer if our Paleolithic ancestors have likely consumed it over millions of years?
  • Is one processing method (i.e., smoking) better than another (i.e., dehydration)?
  • What does the label “uncured” or “minimally processed” mean?
  • Is curing using celery juice powder, a natural source of nitrates, healthier than conventional curing?
Cancer

As so often the case, not all questions have simple answers. But in this article, I will tell you in plain English what I could find out. Let’s start with clarifying some terminology, before jumping into the findings of the study. Finally, I will tell you why, despite the study’s findings, I continue to consume processed meat snacks from Wild Zora* and Sogo Snacks*.

Terminology

Red Meat Definition

Red meat includes beef, veal, pork, lamb, mutton, horse, and goat. Technically, it also includes dog, cat and any other mammalian muscle meat, but those are usually not part of my menu. It does not include “white meat” from poultry or seafood.

Processed Meat Definition

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 processed meats may also contain other red meats, poultry, offal, or meat by-products such as blood. Examples of processed meat include hot dogs (frankfurters), ham, sausages, corned beef, and biltong or beef jerky as well as canned meat and meat-based preparations and sauces.

WHO

As you can see, the term processed meat is not limited to red meat but also includes poultry and meat by-products but not seafood. It is also important to point out that many products that are labeled as “unprocessed” or “uncured,” such as the bacon we regularly buy at Whole Foods, are, indeed, processed.

What the label “unprocessed” often refers to, is the absence of nitrates, other than the ones naturally occurring in celery juice powder. In my opinion, that label is misleading and confusing as far as the risk of cancer is concerned.

Paleo diet: The risk of cancer from eating red or processed meat

Red And Processed Meat And Colorectal Cancer

The National Institute of Health (NIH), published the full study titled “Red and Processed Meat and Colorectal Cancer Incidence: Meta-Analysis of Prospective Studies” and it is worth taking a look. Don’t take anyone’s word on important, health-related issues.

Check out the source! In many cases that means, reading the study instead of the interpretation of your favorite news outlet, or my blog.

Background

Several past studies have suggested that there is a link between processed and red meat and certain types of cancer. With the availability of new prospective studies, an expert panel of the IARC conducted a new meta-analysis. A meta-analysis is a statistical analysis that combines the results of multiple scientific studies.

The evidence that red and processed meat influences colorectal carcinogenesis was judged convincing in the 2007 World Cancer Research Fund/American Institute of Cancer Research report. Since then, ten prospective studies have published new results. Here we update the evidence from prospective studies and explore whether there is a non-linear association of red and processed meats with colorectal cancer risk.

IARC

Conclusion

The conclusion of this new study hasn’t significantly changed from what earlier studies reported. It still suggests that there is a link between processed and red meat and certain types of cancer.

High intake of red and processed meat is associated with significant increased risk of colorectal, colon and rectal cancers. The overall evidence of prospective studies supports limiting red and processed meat consumption as one of the dietary recommendations for the prevention of colorectal cancer.

IARC
The risk of cancer from eating red or processed meat
How real is the risk?

The Paleolithic Diet and (red) meat

A significant source of protein for our Paleolithic ancestors were animals. Depending on where the early humans lived, that was either meat, seafood or a combination thereof.

Most of the meat consumed back in the days was raw until early hominins began cooking food around 1.9 million years ago. But even then, fire may have only been used to defrost frozen meat, the only way our ancestors had to conserve meat.

Based on the available meat sources, it’s not hard to imagine that specifically red meat played a significant role in the dietary habits of our ancestors. From an evolutionary perspective, how can we resolve the issue of red meat and cancer? In other words, how can something our ancestors ate for millions of years cause cancer?

Shouldn’t evolution have taken care of this by making our bodies immune or by dropping red meat from our menu?

The Paleo Diet
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Potential Risk Factor: Temperature

The solution to this problem could be that our ancestors ate raw instead of cooked meat. The IARC study found that “cooking at high temperatures or with the food in direct contact with a flame or a hot surface, as in barbecuing or pan-frying, produces more of certain types of carcinogenic chemicals, such as polycyclic aromatic hydrocarbons and heterocyclic aromatic amines.”

Unfortunately, the IARC working group didn’t have enough data to conclude if the way meat is cooked affects the risk of cancer. Personally, I consider lower heat and no direct contact with open flames, the safer option. If that is a correct assessment, hopefully, future studies will show.

The risk of cancer from eating red or processed meat

Recommendation Regarding The Consumption Of Meat

When we started the Paleo diet over two years ago, our meals often consisted of red meat and veggies. Like so many others, unfamiliar with or new to the Paleo lifestyle, that’s what I thought the Paleo diet was all about. These days, we eat more poultry and seafood than red meat. In fact, I would argue that we eat as much seafood as we eat red meat.

The evidence that consuming red meat increases the risk of cancer is not very strong.

The cancer risk related to the consumption of red meat is more difficult to estimate because the evidence that red meat causes cancer is not as strong. However, if the association of red meat and colorectal cancer were proven to be causal, data from the same studies suggest that the risk of colorectal cancer could increase by 17% for every 100 gram portion of red meat eaten daily.

WHO

When asked to quantify the risk, the WHO responded:

However, consumption of red meat has not been established as a cause of cancer.

WHO

But even if it wasn’t because of the potential risk, I wholeheartedly agree with The WHO’s recommendation of limiting the intake of red meat. Why? Because I believe in a healthy and balanced diet. Plus, there are multiple sources of animal protein available, and red meat is just one of them.

By following a balanced approach to our protein intake, you are automatically limiting your consumption of red meat. That is a safe bet until scientists have more data and definitive answers.

The Paleolithic Diet And (Processed) Meat

Processing food, other than by accident, was not part of our ancestor’s life. As a result, it is safe to conclude that early humans did not consume processed meat. So strictly speaking, processed meat is not considered Paleo.

However, the modern Paleo diet doesn’t suggest to live like our Paleolithic ancestors but rather that we mimic their approach based on our modern life. As a result, many make processed meat part of their dietary habit, including me.

Unfortunately, there is sufficient evidence to suggest that processed meat causes certain types of cancers in humans. That’s why the IARC classified processed meat as Group 1 carcinogenic to humans. You may have heard that tobacco smoking and asbestos fall into the same category.

But it is important to understand that they are not equally dangerous. The classification merely describes the strength of the scientific evidence and not the level of risk.

The risk of cancer from eating red or processed meat
Processed meat

So How Real Is The Risk?

According to the Global Burden of Disease Project, 34,000 people die each year worldwide due to diets high in processed meat. Additionally, the IARC estimates that every 50 gram (1.8 oz) portion of processed meat increases the risk of colorectal cancer by 18%.

According to the National Cancer Institute, the average lifetime risk of developing colorectal cancer is 6%. By consuming 50 grams of processed meat per day, you increase your risk to 7%. If you ate 100 grams of processed meat per day, you would increase your risk to 8%.

Do Processing Methods Influence The Risk?

No matter what dietary lifestyle you have, if you care about your health, you should stay away from processed food. Processing food alters its ingredients and often adds unhealthy ingredients. But sometimes processing is necessary to make food stay fresh longer.

A good example of processed but healthy food is olives in salt water or lactic acid. Unfortunately, processed food that’s healthy is the exception and not the rule.

Regarding meat, there are various processing methods that may influence your risk of developing cancer. Some of the more well-known methods include salting, curing, fermentation, smoking, dehydration, etc.

I reached out to the IARC to find out if certain processing methods, such as low-temperature dehydration, or curing using celery juice powder are better than others. Unfortunately, scientists don’t have a clear answer on that yet.

Different preservation methods could result in the formation of carcinogens (e.g. N-nitroso compounds), but whether and how much this contributes to the cancer risk is unknown.

IARC

Potential Risk Factor: Nitrates And Nitrosamines

Nitrates are often used for preserving and processing food. The problem with nitrates is that they convert into nitrosamines in acidic environments, such as your stomach. Nitrosamines are a carcinogenic and one of the main risk factors for processed food.

Certain vegetables, such as celery, also contain nitrates. That’s why some manufacturers use celery juice powder for curing meat. However, meats processed with such alternative curing methods contain residual nitrite and nitrate that is indistinguishable from those found in traditionally cured products, according to research from Gary A. Sullivan, Ph.D., University of Nebraska-Lincoln.

You may wonder why consuming celery doesn’t increase your risk of cancer. That is because fresh celery contains antioxidants, including Vitamin C. Those antioxidants, inhibit the conversion of nitrates to nitrosamines in the body.

There is even research suggesting that Vitamin C can inhibit the formation of nitrosamines, which would explain why consuming celery poses no risk of developing cancer.

It is fairly obvious that a healthy diet, rich in food containing vitamins and antioxidants, reduces the risk of chronic disease, including cancer. If that means that an otherwise healthy diet provides a counter-balance to the consumption of processed meat, has not been established yet.

Recommendation

In our family, we occasionally consume processed meats such as “uncured” bacon, salami or prosciutto. Remember, the term uncured just means that alternative curing methods were used.

That often includes the use of celery juice powder as a source of nitrates. From a risk perspective, there is no evidence that nitrates from celery juice powder are any healthier than commercial nitrates.

So why eat processed meat at all? I occasionally eat processed meat for dinner, because cold meat is an Austrian tradition that I grew up with. Hanging on to that tradition increases my risk of developing cancer by less than 1%. That is a risk I am willing to take.

When I buy cold meat, I try to choose the least processed options or labels that use the least-invasive processing methods. I know that there is no scientific evidence that one processing method is better than the other. But the “less is more” strategy has worked out more often than not for me.

For traveling it is more challenging to find a snack that provides a decent source of protein. So meat snacks are handy and easy to consume. That’s why we like and recommend meat snacks from Wild Zora and Sogo Snacks.

Meat Snacks From Wild Zora And Sogo

Both Wild Zora* and Sogo Snacks* use only the highest-quality ingredients for their products, including grass-fed meat. So you cannot compare them to most other meat snacks, which usually contains such ingredients as sugar, soy sauce, more sugar, artificial flavors, etc.

Wild Zora
Wild Zora Snacks

The Wild Zora BBQ Beef Bars, for instance, contains only the following ingredients: 100% Grass-Fed Beef, Organic Vegetables & Fruit (Red Bell Pepper, Tomato, Unsulfured Apricots, Dates, Kale, Garlic, Celery), Chipotle Pepper, Ancho Chili Pepper, Sea Salt, Spices.

Wild Zora uses a more time-consuming, and more expensive, low-heat dehydration to preserve the ingredients. According to them, that reduces the formation of carcinogenic chemicals.

So the big difference here is that some companies “bake” or “cook” their meat protein-based products at high heat in order to dehydrate them more quickly, which then causes the formation of the compounds you mentioned. The worst offenders would be grilling, frying, and broiling, but baking too, if it causes a browning action. At Wild Zora we do not do any of these things! We use a more time-consuming (and to be honest, more expensive) low-heat slow-dehydration method which does not cause any browning at all, and so formation of these dangerous compounds is avoided.

Wild Zora

Sogo Snacks
Sogo Snacks

The Sogo Snacks Beef Snack Sticks contain the following ingredients: 100% grass-fed and finished beef, water, sea salt, citric acid, celery juice, black pepper, red pepper, garlic, coriander, white pepper. Sogo Snacks uses smoking as a method of preserving the meat. When I asked Dan, the founder of Sogo for a statement about processed meats, he pragmatically responded:

From my perspective, consumers have to decide if eating a processed product with very simple ingredients, no sugar, no allergens, grass fed, etc., that has at most a 1% increased lifetime risk, will help them eliminate other foods or habits that are even more harmful.

Sogo Snacks

I can certainly identify with that statement!

Overall, we very much like both brands and enjoy their snacks on occasion. Especially when traveling or when no other healthy sources of protein are immediately available. They most certainly beat other types of snacks that have a lot of processed carbs, including sugar!

Red Meat and Cancer?

Most food-related studies rely on feedback from participants as a source of data, such as food journals. Unfortunately, there is an inherent risk of getting incorrect or incomplete data. Additionally, it is almost impossible to isolate certain food groups for a study.

For example, you can’t feed a group of people only processed meats for years and nothing else – just to find out how it affects the participants. It’s also likely that those who eat a lot of processed food, including meat, have otherwise unhealthier dietary habits than, for example, someone on a Paleo diet who exercises regularly.

But that doesn’t mean, we should ignore those studies. Keep in mind, properly executed scientific studies are the best tool we have available to determine facts. There is nothing better or more reliable. As a result, I do acknowledge the risk of cancer from eating red and processed meat. But I will continue to consume both red and processed meat in moderation.

For further reading, I recommend the Q&A on the carcinogenicity of the consumption of red meat and processed meat.

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