March is Colorectal Cancer Awareness Month: a perfect time to direct attention to the tail end of your digestive tract. Contrary to what many believe, the colon isn't an inert hollow tube that simply serves as a reservoir for waste until you can find a toilet. Rather, it's a complex organ that performs the essential function of facilitating balance of fluid and electrolytes in the body in addition to its role in storing and eliminating waste. Equally important -- if not moreso -- the colon hosts a crucial ecosystem of bacteria that plays a vital role in health. Unfortunately, many of us fail to appreciate just how central the colon is to our health and survival until something goes wrong.
Colorectal cancer is the second leading cause of cancer deaths in the U.S., claiming the lives of more than 50,000 Americans annually. The vast majority of cases occur in people over age 50, and African Americans have the highest rates of colon cancer incidence among all racial groups.
As scary as these stats may sound, a large percentage of cases are preventable. Here are 10 lifestyle changes that may be of benefit in colorectal cancer risk reduction:
1. Reduce your alcohol intake. When it comes to cancer prevention, less (alcohol) is more. Alcohol use is a known risk factor for colorectal cancer -- among other cancers -- with risk increasing as alcohol intake increases. If you choose to drink, try limiting your intake to no more than one drink daily.
2. Quit smoking. Smoking is not just a risk factor for lung cancer, but for all digestive system cancers, including colorectal, stomach and esophageal. Make the decision to quit this month, once and for all.
3. Get moving! Sedentary lifestyles are associated with an increased risk of digestive system cancers. Evidence supporting a significant protective effect of physical activity on colorectal cancer risk is particularly strong. The body of available research suggests that the most active adults have a 40 to 50 percent reduced risk of developing colon cancer, compared to the least active adults. Importantly, the protective effect of exercise appears to be independent of weight status, meaning that regular physical activity appears to reduce risk of colon cancer even in people who are overweight or obese. So if regular exercise hasn't yielded the weight loss you've hoped for, don't be discouraged: There are substantial health benefits to physical activity that may not show up on the scale.
4. Get serious about weight loss. Obesity is a strong risk factor for colorectal cancer, and researchers estimate that risk increases about 15 percent with each five additional points of body mass index beyond the upper end of normal range. So, for example, weight loss that results in a reduction of BMI from 35 to 30 would be expected to result in about a 15 percent risk reduction.
5. Eat less red meat. There is strong evidence supporting high intake of red meat as a risk factor for colorectal cancer. One large study that examined the diets of adults aged 50 to 71 showed that people with the highest intakes of red meat -- an average of 5 ounces per day -- had a 24 percent greater risk of developing colorectal cancer compared to those with the lowest intake -- an average of about half an ounce per day. It has been proposed that multiple mechanisms may be at play, including the type of iron found in red meat (heme iron) and increased exposure to carcinogens called HCAs that are produced when red meat in particular is charred or cooked at a high temperature. If you can't imagine life without red meat, try thinking of red meat as a garnish to veggie-heavy meals such as stir fries or salads, rather than a center-of-the-plate affair. And consider lower-temperature cooking methods such as braising, boiling or even sautéing instead of broiling or grilling.
6. Avoid foods preserved with sodium nitrite. As you go about reducing your meat intake, start with "pink" processed meats like bacon, salami and hot dogs. These foods -- as well as other processed lunchmeats -- are commonly preserved with sodium nitrite. When sodium nitrite encounters stomach acid during digestion, it may convert to a compound called a nitrosamine, which is a known carcinogen. Indeed, both high intake of nitrites and processed meats have been associated with increased risk of colorectal cancer compared to lower intakes. If you choose to consume processed meats, look for nitrite-free products, such as those marketed by the Applegate Farms brand.
7. Eat more fruits and non-starchy vegetables. Now that you've freed up all that space in your diet from cutting back bacon and red meat, what will you replace it with? How about fruits and non-starchy vegetables -- such as dark leafy greens, beets, squashes, bell peppers, tomatoes, asparagus, carrots, cauliflower, cabbage, broccoli and green beans? These foods seem to have a protective effect against colorectal cancer, likely as the result of a combination of factors that includes their antioxidant content, fiber and species-specific phytochemicals.Research has shown that people with diets highest in fruit and non-starchy veggies have lower risk of developing digestive system cancers (including colorectal) compared to people whose diets contain the least amount of these foods. Garlic may be particularly beneficial, so use it liberally.
8. Get plenty of fiber, preferably from whole foods. Beyond the specific benefits of fruits and veggies, dietary fiber from other plant-based sources may confer a protective benefit against colon cancer. Fiber is non-digestible plant material that travels through the length of the intestines and arrives to the colon intact. Once there, it may trap dietary carcinogens in the stool, escorting them out of the body expeditiously before they have the chance to cause trouble. Fiber also provides fuel to the resident bacteria living in our guts, which produce cancer-preventing byproducts called short chain fatty acids. Fiber-rich foods like beans, seeds, nuts, oatmeal and bran cereal are preferable to fiber-fortified, highly-processed foods because the bulk of research investigating the chemoprotective effect of high fiber diets examined fiber from whole foods -- which tends to differ from the laboratory-made types of fiber added to functional foods. Snack on edamame, dry roasted chickpeas or popcorn instead of 90 calorie fiber bars or brownies. Have oatmeal with nuts instead of a packaged cereal bar for breakfast. Choose lentil or split pea soup for lunch instead of a sandwich.
9. Take a vitamin D supplement . Low levels of vitamin D in the blood have been identified as a risk factor for colorectal cancer. Since Vitamin D is not a particularly prevalent dietary vitamin, many people require some degree of supplementation -- at least during the non-summer months. This is particularly true of people: who live north of 40 degrees latitude (Washington, D.C.-ish); who avoid the sun in summertime or wear sunblock; who have darker complexions; and who do not consume fortified dairy products (or non-dairy equivalents) regularly.
10. Drink your milk. If you like and tolerate cow's milk, here's some good news: Consuming it regularly may have a modest protective effect against colorectal cancer. Higher intake of dietary calcium (including from supplements) and liquid milk in particular has been associated with decreased risk of developing colorectal cancer compared to lower intake. Importantly, relying on cheese as the primary source of calcium may not be the optimal strategy to help reduce colorectal cancer risk. Research suggests that high intakes of cheese may actually have the opposite effect, possibly due to its concentrated saturated fat content.
If this laundry list feels intimidating, consider that these lifestyle changes are quite synergistic. Eating more fruit and non-starchy vegetables generally results in increased fiber intake -- thus killing two birds with one stone. It may also help you lose weight, in which case that's three items you can knock off the list from one single change. Similarly, drinking less alcohol and getting more exercise tend to contribute to weight loss. If you take a combined calcium and vitamin D supplement -- or up your intake of low-fat dairy products fortified with Vitamin D -- you'll address two risk factors in one fell swoop. Eliminating nitrite-preserved meats like bacon and hot dogs may help reduce your intake of total red meat as well, thereby magnifying the risk reduction.
Finally, if you have a loved one who's 50 or older, nag him to get his routine colon screening. Colonoscopy not only detects cancer early -- when it's most treatable -- but also enables the removal of pre-cancerous polyps before they can turn into cancers. So offer to drive your 50-something friends to and from their procedure, and assure them that while the prep for a routine colonoscopy may be mildly unpleasant, it need only be done once every five to 10 years in healthy people. Colonoscopy is done under sedation; it's a short procedure that's not at all painful. An ounce of prevention is worth a pound of cure.