Colon cancer cases are on the rise in people under the age of 50, and it’s not clear why. Some experts believe obesity is a factor since colon cancer is more common in people who are overweight or obese, but why? As you might expect, scientists believe diet plays a role.
Since obesity is a risk factor for cancers of the colon and rectum, consuming too many calories raises the risk, but diet quality is a factor too. There’s some evidence that eating a diet rich in fruits and vegetables, and other plant-based foods high in fiber may lower the risk. Another question scientists raise is whether eating red meat increases the risk of developing colon cancer. What does science say about a link between red meat and colorectal cancer risk?
What Health Agencies Say about Red Meat and Colon Cancer
After reviewing studies looking at the role that red and processed meat plays in cancers of the colon and rectum, the World Health Organization reported that red meat is a probable carcinogen. This means it likely causes cancer but needs more research. Plus, they believe that processed meat is a carcinogen in humans. So, the World Health Organization takes a stronger stance against processed meat than it does red meat, although it raises concerns about both.
In a 2018 report, the World Cancer Fund reached a similar conclusion about processed meat. It likely raises the risk of developing colorectal cancer. However, the link between unprocessed red meat and colon and rectal cancers is probable but not definitive. The most compelling evidence that red meat increases colorectal cancer risk is for tumors of the left side of the colon.
How Red Meat Could Raise Colorectal Cancer Risk
There are several reasons red meat could increase the risk of cancer. For one, red meat produces hydrocarbons and polycyclic amines (PACs) when you cook it to high temperatures. Hydrocarbons are the black marks you see on a steak when you place it on a grill. You can’t see polycyclic amines, but they, too, are probable cancer-causing chemicals. Meat that’s higher in fat produces the most PACs.
You can lower the risk of exposure to these carcinogens somewhat by eating leaner cuts of meat. Also, marinating meat in a marinade that contains antioxidant herbs and spices reduces PACs. In one study, a marinade with contains oregano, onion, basil, parsley, onion, and red pepper was effective. Plus, these spices offer other anti-inflammatory benefits.
On the plus, several randomized-controlled trials did not support the idea that red meat or processed meat increases the risk of cancers of the colon and rectum. Based on these observations and the previous findings from observational studies, it’s unlikely that eating red meat in moderation dramatically increases cancer risk.
One study found that eating 100 grams of red meat daily boosted the risk of colorectal cancer by only 12%. That’s not a huge increase in risk. Another, published on the American Institute of Cancer Research site, showed that eating more than 12 to 18 ounces of red meat each week may raise the risk of colorectal cancer.
You also have to consider diet as a whole. A small serving of red meat each day combined with fruits and vegetables probably won’t affect colon cancer risk as much as eating a large steak each day with a plate of French fries. Eating steak with an order of broccoli, a colorful salad, and washing it down with a cup of green tea might have a less negative effect on colon cancer risk if plant-based foods are protective.
Plant-based Foods May Be Protective
It’s not just what you don’t eat but what you do eat that affects your odds of developing colorectal cancer. One study found that eating three servings of whole grains each day reduces the risk of colorectal cancer by 17 percent. The same applies to fruits and vegetables because of their high fiber content.
Fiber acts like a broom for the intestinal tract, it sweeps out toxins that might contribute to cancers of the intestinal tract. The phytonutrients in whole grains and produce, including compounds with antioxidant and anti-inflammatory activity, may also explain why these foods are linked with a reduced risk of colorectal cancer.
Despite a lack of definitive research, it’s still smart to eat red meat in moderation and avoid processed meat. How do red and processed meat differ? Processed meat comes in all types and includes options such as bacon, sausage, smoked meat, salted meat, and cured meat. Scientists believe the preservatives used to process these meats, particularly sodium nitrates, may play a role in promoting colorectal tumor growth. The human intestinal tract converts sodium nitrates to N-nitrosamines that are cancer-causing agents.
The Bottom Line
It’s not conclusively proven that eating red meat increases the risk of colorectal cancer. If there is a link, the risk is modest. Still, if you are concerned about your risk of colorectal cancer, it may be worth cutting down on the amount of red meat and processed meat you eat. You may also lower your risk by adding more plant-based foods to your diet. As with most things, moderation is key.
Also, know your colon cancer risk. If you have several other family members who had it, you may be at greater risk too, and need earlier colon cancer screening. There are several genetic syndromes that raise the risk. Fortunately, most colorectal cancer is preventable through getting a screening colonoscopy and removing any pre-cancerous polyps before they develop into a malignancy.
References:
- Bouvard V, Loomis D, Guyton KZ, Grosse Y, Ghissassi FE, Benbrahim-Tallaa L, Guha N, Mattock H, Straif K, International Agency for Research on Cancer Monograph Working Group/ Lancet Oncol. 2015;16(16):1599. Epub 2015 Oct 29.
- Comprehensive Reviews in Food Science and Food Safety. Volume18, Issue 6, November 2019
- Pages 1812-1824
- American Institute for Cancer Research. “Processed Meats Increase Colorectal Cancer Risk, New Report”
- Cancer.org. “Colorectal Cancer Rates Rise in Younger Adults”
- WebMD.com. “Marinate Meat for Healthy Grilling?”
- American Institute for Cancer Research. “Reducing Colorectal Cancer Risk by Cutting Red Meat”
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