Colorectal cancer and red meat

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Does eating more red meat increase one’s chances of colorectal cancer?

Quote: “…the judgements and conclusions from a dietary health perspective have not been met with scientific consensus” (Alexander and Cushing, 2010).

Red meat and colorectal cancer

Despite a long and arduous attempt by researchers to establish a clear link between the consumption of red meat and colorectal cancer (colon and rectal), research findings thus far do not warrant a large scale avoidance of red meat consumption. At present, the research findings are just not strong/conclusive enough to warrant health advice to substantially restrict red meat in one’s diet. Some studies have found only very weak associations between red meat intake and colorectal cancer, whilst other factors and variables in one’s lifestyle may be more important in what causes cancer, such as: refined carbohydrates; excess alcohol; low intake of vegetables; smoking; and low levels of physical activity. On the other hand, some studies have found positive effects of red meat consumption! Plus, any association between red meat and cancer in women appears considerably less than for men [in that particular study, vegetarian women had a higher incidence of breast cancer]

red meat cancerBenefits of red meat

Red meat contains a wide array of micronutrients. These include: all essential amino acids (histadine, lysine, threonine, methionine, phenylalanine, tryptophan, leucine, isoleucine and valine); iron, zinc, selenium, and vitamin B6, B12 and vitamin D. It is also significant source of omega-3 polyunsaturated fatty acids (PUFAs) (Aykan, 2015)

How does this affect my diet?

It’s probably prudent not to eat red meat every day, and instead to eat a variety of meat (and fish). In addition, as long as red meat is not consistently eaten “overcooked” or burnt, which may be a factor in what causes cancer, and until the research conclusively says otherwise, advice to substantially reduce red meat consumption on the premise that it will decrease one’s chance of cancer appear unsubstantiated. Ensuring one consumes a wide variety of whole, fresh and unrefined food, has a generous serving of vegetables each day, takes part in some form of physical activity and does not consume alcohol to excess would appear more warranted guidance with regard to cancer prevention.

NB. by “red meat” I mean to include: beef (steak/mince), pork (chop) and lamb, and would generally recommend non-processed forms of red meat.

red-meatAddendum

Since I first wrote this short blog post, there has been a media frenzy surrounding red meat consumption. This is due, in large part, to the press release by the International Agency for Research on Cancer (IARC) In October of 2015. You can read the press release HERE. Simply, after a large investigation looking across hundreds of studies, the IARC deduced that red meat is “probably carcinogenic to humans”. Processed meat, on the other hand, was classified as “carcinogenic to humans”. Read the quote below:

After thoroughly reviewing the accumulated scientific literature, a Working Group of 22 experts from 10 countries convened by the IARC Monographs Programme classified the consumption of red meat as probably carcinogenic to humans (Group 2A), based on limited evidence that the consumption of red meat causes cancer in humans and strong mechanistic evidence supporting a carcinogenic effect. This association was observed mainly for colorectal cancer, but associations were also seen for pancreatic cancer and prostate cancer

Thoughts:

For further reading on the topic, see THIS POST by the guys at Examine. They do a nice job of simplifying the topic, and explain that although red meat has mechanistic links to cancer i.e. yes, scientifically speaking, it ‘can’ facilitate cancer growth, on an individual basis it is statistically highly unlikely to be cause/sole cause of one’s cancer. They also have another article HERE which is also worth reading.

As written above, colorectal cancer tends to found in cases where unhealthy behaviours are clustered together. These include: high overall caloric intake; obesity; low vegetable intake; low levels of physical activity; smoking; and alcohol consumption. Just like unhealthy behaviours, ‘healthy’ behaviours tend to be found together also. From the literature research thus far, it would appear highly unlikely that someone would suffer from colorectal cancer if they ate red meat regularly yet exercised regularly, avoided smoking, drank in moderation, consumed a large number of vegetables and fruit, and especially vegetables of the cruciferous variety, and mostly ate unprocessed red meat. In such cases, red meat consumption is most probably not worth worrying about, and focus/attention on health improvement should be diverted to other areas of diet/lifestyle.

That being said, there are a few things you can do to mitigate against the possible harmful effects of regular red meat consumption. These include:

  • regularly consume high-fibre food, like fruit, oats, and vegetables
  • covering/wrapping meat in foil when roasting
  • minimising exposure to flame
  • avoiding eating red meat ‘well done’ or overcooked
  • intersperse the consumption of red meat with other protein source, like white and oily fish