Did you know colon cancer is the second leading cause of cancer death? You might think colon cancer is an issue primarily later in life, but rates of new colon malignancy are rapidly increasing among younger people, under the age of 50. Yes, this “old age” cancer is striking men and women during the prime of life. The disturbing rise in new colon cancer diagnoses has caused the American Cancer Society to revise its guidelines for colon cancer screening. Previously, guidelines recommended initial screening at age 50 for people at average risk. But the new recommendations urge average-risk men and women to get their first screening at age 45.
Of course, we’d like to do what we can to prevent colon cancer. It’s not clear why more people are getting a colon cancer diagnosis before the age of 50. Some colon cancer victims are as young as their 20s and 30s, something that was almost unheard of decades ago. Experts believe rising rates of obesity play a role in the disturbing rise in colon cancer in younger men and women. Research shows obesity increases the odds of developing colon cancer by 30%. Therefore, one way to lower the risk is to stay a healthy body weight. Exercise can help with that! But are there other ways exercise can lower the odds of a colon cancer diagnosis?
Exercise and Colon Cancer Risk
How much can regular physical activity lower the risk of this common form of cancer? According to one study, 12-14% of cancers in the colon could be prevented with regular exercise. Most studies show a link between physical activity and a reduction in colon cancer and some show a drop in the risk of rectal cancer as well. According to research, vigorous exercise lowers the risk the most and there may be a certain threshold amount of exercise needed to significantly drop the risk. This seems to be about 4 hours of relatively vigorous exercise weekly. It sure strengthens the case for doing HIIT training, doesn’t it?
Colon Cancer, Exercise, and Polyps
Many colon malignancies begin as a small polyp that transitions to colon cancer. However, some polyps carry a higher risk than others. With some types of colon cancer screening, you can detect pre-malignant polyps early and remove them before they become full-blown cancers. That’s why experts regular colon cancer screening dramatically lowers the risk in people who get it. You can find and remove polyps while they’re still small. In fact, the rate of colon cancer is dropping in people over the age of 50 due to aggressive screening.
Interestingly, exercise early in life may provide protection against colon malignancies. A new study published in the journal Nature found that being physically active during adolescence and early adulthood was linked with a lower risk of colon polyps called adenomas. This information comes from the Nurses’ Health Study 2 that followed more than 28,00 women for 22 years. That’s important since colon cancers arise from adenomas or polyps. Usually, colon cancer begins as a polyp with precancerous potential. Slowly, genetic changes take place within the cells of the polyp that cause them to become cancers. If exercise reduces polyp formation, as this study suggests, it can reduce the risk of colon malignancies later in life. So, staying active as early in life as possible helps, but working up a sweat later in life is beneficial too.
How Does Exercise Lower Colon Cancer Risk?
The protective effects of exercise on colon cancer risk are likely multifactorial. As mentioned, physical activity lowers the rate of obesity and that’s a risk factor for colon tumors. But there are a variety of other ways exercise helps keep the colon healthy. We know that exercise, in moderation, has beneficial effects on immune function. The immune system helps vanquish tumor cells that could grow into cancer. Plus, it helps reign in an overactive immune system and prevents tissue-damaging inflammation. We know that inflammation is a driver of a number of health problems, including cancer.
Another way exercise may lower the risk of colon cancer is by improving insulin sensitivity. When cells are more sensitive to insulin, less insulin circulates in the bloodstream. That’s important because insulin and its close cousin, insulin-like growth factor one (IGF-1), promote the growth of certain types of tumors, including colon cancer. In support of this, people with type 2 diabetes have a higher rate of colon cancer. Also, exercise quickens the rate at which food moves through the colon. That’s beneficial because there’s less time for dietary components to interact with the wall of the colon.
What You Can Do
The take-home message? Stay physically active, of course, and include vigorous exercise in your fitness routine. Other ways to lower your risk:
· Follow your body weight closely to avoid obesity.
· Don’t smoke or drink more than 1 alcoholic drink daily.
· Eat more fruits and vegetables and limit processed meat in your diet.
Also, know your family history and ask your physician when you should get your first screening test and which screening method is best for you. Certain genetic conditions greatly increase the risk of developing colon cancer. If you’re at high risk based on genetics, you may need to begin screening before age 45. The screening method most doctors still recommend is a screening colonoscopy. The advantage of this method is you can see and remove polyps at the time of screening. However, there are more options available, including stool DNA tests and a fecal occult blood test. Ask your physician about which is right for you – but keep exercising. It’s a lifestyle habit that will help you reduce the risk of a variety of life-shortening health problems and get more out of life too!
· Centers for Disease Control and Prevention. “Colorectal Cancer Statistics”
· National Cancer Institute. “Obesity and Cancer”
· PLoS One. 2013;8(1):e53916. doi: 10.1371/journal.pone.0053916. Epub 2013 Jan 17.
· Sports Med. 2004;34(4):239-52.
· British Journal of Cancer. “Physical activity during adolescence and risk of colorectal adenoma later in life: results from the Nurses’ Health Study II” (2019)