Last week, the specialised arm of the World Health Organization (WHO), International Agency for Research on Cancer (IARC) released a 1.5-page short summary sheet– on the carcinogenicity of red meat and processed meat.  The IARC committee gathered 22 scientists from 10 countries to systematically go over 800 studies done in the past 10-20 years on the cancer-causing effects of eating processed meat and red meat.  They came up with the summary sheet mentioned above and will follow up with a highly detailed monograph in the coming months if not years on their findings.  You’ve probably already come across these articles somewhere as it was mentioned on probably every media outlet out there.

After painstakingly combing through all the articles and research of the summary sheet, I’ve summarised the top 10 things you need to know about IARC and that report so you can come up with your own conclusions on how to react to this report.

Here is Olive Branch’s take on it:

1.  Red meat refers to unprocessed mammalian muscle meat – for example, beef, lamb, pork, horse, goat, veal, mutton, including minced and frozen and is cooked.

2.  Processed meat refers to meat that has been treated through salting, curing, fermentation, smoking and other practices that enhance flavour or preservation.

3.  IARC uses a 4-point rating system to evaluate the agent to determine what is the likelihood of it causing cancer.  For this study, it is looking at colorectal cancer specifically.

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4.  Processed meat is given a rating of 1.  Red meat is given a rating of 2A.

5.  Dose-Response is the key to understanding how much of something can lead to risk.  The ‘dose’ is how much exposure of the agent will translate to actual risk for you, the ‘response’.

For example, alcohol in moderate amounts (1-6 drinks per week) has been shown to reduce the risk of heart disease.  But if you change the dose to 5 drinks per day, then your risk of getting a disease goes way up (response!).

IARC’s report concluded that the dose-response relationship of consuming 50g/day of processed meat will increase your risk by 18%; and consuming 100g/day of red meat will increase your risk by 17%.


“a majority of the Working Group concluded that there is sufficient evidence in human beings for the carcinogenicity of the consumption of processed meat.”


6.  The negative effects of TMAO compounds are controversial as it’s been talked about previously but is believed to be linked to colon cancer.  Basically, there’s a type of protein in red meat that gets metabolised in the gut by your microflora and the byproduct are these TMAO compounds which can lead to cancer.  However, some studies show that the type of microflora you have can greatly influence how much TMAO you produce.  And your microflora is quite unique from individual to individual.

7.  High-heat cooking like frying or grilling is also a main cause for cancer in eating red meat as charring the meat creates HCA compounds and damages the gut.  As a side note: this is why taking popular diet fads literally like the caveman/paleo diet is not advisable as cooking with open fire is generally not the healthiest thing to do.  However, studies have shown that you can reduce the damage by eating broccoli and Brussel sprouts (cruciferous vegetables) as well as marinading your meat prior to cooking.

8.  As a general rule, when food is consumed in the presence of other food the effects can vary greatly.  Processed meat and red meat’s harmful NOCs are caused by the haemoglobin in the blood (the pigment that makes it red) as it reacts in the intestines.  But when you eat them with green vegetables, the chlorophyll molecules help to reduce the damage in the intestines.  No wonder creamed spinach is a staple side dish in classic steakhouses.  They were on to something!


“The Working Group concluded that there is limited evidence in human beings for the carcinogenicity of the consumption of red meat.”


9.  The IARC study also did not consider these relevant factors such as whether the meat is grain-fed or grass-fed, the cooking method, cooking temperature, the cuts of meat, the use of antibiotics or hormones.  Studies have shown that these factors can have a huge impact on the quality of meat.

10.  Something that is labelled “carcinogenic” is fairly common.  Here are some examples from IARC’s list:

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Even with IARC’s infinite wisdom, it is still unknown exactly how much red meat consumption will lead to cancer.  If you tempt fate, and you eat red meat every day, or worse, processed meat every day, then you’re just asking for it.

Don’t forget, red meat also contains a lot of highly nutritious elements that do make up a balanced diet.  So don’t freak out and ban red meat from your diet entirely.  But it’s probably a good idea to reduce the amount you consume on a regular basis.

Until the official monograph from IARC comes out, I would err on the safe side and be a little more cautious than before and think of this report more as a “Take Care” label on red meat.

In the end, I can’t think of any better situation that exemplifies the phrase: moderation is key.


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