Understanding the Link Between Red Meat and Colon Cancer
It’s probably safe to say that your colon is not usually top of mind… but it should be. We usually think of it as a sewage system and while it’s true that your colon sees a lot of waste pass through, the colon also plays an ever more interesting role in our health. Even the basics are critical to human health: the colon absorbs any remaining fluids and electrolytes it can. But the real digestive excitement happens because of the trillions of microbes living within it’s walls. Research is looking into the digestive, immune and neurological impact of a healthy digestive flora and it all happens in colon land.
Another reason you should be mindful of your colon is that colorectal cancer is the third most commonly diagnosed cancer in Canada (stat from Canadian Cancer Society). If you are over 50, you should be screened regularly. If you are under 50, you want to live a healthy lifestyle that keeps that colon in tip top shape, just like the rest of you.
It’s Colorectal Cancer Awareness Month, so I wanted to do my part and talk nutrition for the nether regions. While there are many risk factors for colon cancer, I wanted to focus on a contentious dietary risk factor – red meat and processed red meat.
The Low-Down on the Link Between Red Meat and Colon Cancer
Red meat, which includes beef, pork, and lamb, has been in the spotlight for a number of years. Countless researchers have examined the link between increased red meat intake and an increased risk of colon cancer. Their association is still being debated and clarified, but there are several epidemiological studies that present strong evidence for this relationship.
Here’s a brief summary on current research:
- Red and processed meat often contain carcinogenic compounds, such as haem, nitrites and nitrates, and heterocyclic amines (HCAs) and polycyclic aromatic hydrocarbons (PAHs).
- Haem is a red pigment in red and processed meat that damages colon cells, promoting cancer pathways. It can also cause our friendly gut bacteria to do not so friendly things, such as producing carcinogenic N-nitroso compounds (NOCs).
- Processed meat, which include bacon, sausages, ham, and other meats that are either smoked, cured, or salted, often contain nitrites and nitrates, which are commonly used as preservatives. These compounds can be subsequently converted into NOCs in the colon. Other harmful chemicals such as HCAs and PAHs are often found at higher levels in meat cooked at high temperature, such as grilled or barbequed meat (Cancer Research UK, 2014).
- An increased fat intake with meat consumption has been shown to lead to an increase in insulin resistance and more secondary bile acid synthesis, which facilitate carcinogenesis. It is thought that excess saturated fat can increase localized inflammation in the digestive tract.
- A recent study has found that vegetarians have a 22% lower risk for developing all types of colon cancer compared to non-vegetarians. These results have an important implication and further support that our diets are critical in cancer prevention.
So… What’s the next step?
There are many lifestyle changes that can generously reduce your colon cancer risk.
- Firstly, how much and how often can I eat red meat? Current recommendations call for limiting red meat consumption to less than 500 grams (18 oz) per week (AICR). This gives you 3 6 oz servings of red meat per week…although some health professionals would recommend less. So you don’t have to say goodbye to it if you don’t want to, just keep it as a treat.
- Just because you’re limiting your red meat intake, it doesn’t mean that you have to give up meat entirely! You can always go for chicken, turkey, and fish and I highly recommend incorporating more meatless meals into your life for better health, featuring beans, lentils and organic tofu.
- Load up on your fresh plant foods, filled with fibre. Based on a review of studies investigating the association between fibre and colon cancer, fibre has been shown to exert some protective effects against colon cancer. It helps shuffle along cancer-causing compounds out of the body more quickly, minimizing its contact time with the colon. High intakes of dietary fibre have been associated with lower risks of colon cancer, so reach for those whole grains, beans, fruits and veg!
- While the evidence is less clear, calcium may also protect your colon. It does so by binding to bile acids and fatty acids to make calcium soaps, which reduces the ability of these acids to damage colon cells and initiate cell proliferation. Get your dose of calcium from low-fat dairy products, organic tofu, tahini and delicious greens such as spinach.
- In case you’re hungry for more, here are some additional recommendations to reduce your risk.
Total meat consumption in developed countries has been increasing over the years, so it’s time for us to be smart about choosing meat and go for more plants! Aim for a more plant-centred diet that features lots of fibre and fresh fruits and vegetables. A plant-centred diet won’t just reduce your risk for colon cancer – it will reduce your risk for other chronic disease as well as helping you feel energized immediately. The amount of vitamins, minerals, and antioxidants in a plant-centred will outshine a diet anchored by lots of red meat. Not to mention, you will be reducing your exposure to potential cancer-causing compounds as well as the added antibiotics and hormones commonly found in red meat. You don’t have to give up red meat entirely, but just feature a small amount of it in your diet.
Here’s to kicking colon cancer (and other cancers) to the curb with a healthier and delicious diet!
A huge thank you to my student, Esther Huang, for all of her work in putting this post together.