Introduction
March is National Colorectal Cancer Awareness month -- a good time to reflect on the fact that, although inflammatory bowel disease (IBD) increases your colorectal cancer risk by about two to five times the average, colorectal cancer is largely preventable and one of the most treatable cancers if detected early. The most important step you can take is to follow your doctor’s recommendations regarding surveillance colonoscopy. For example, if you’ve had IBD for eight to ten years, your doctor will probably recommend that you schedule a colonoscopy every one to two years. This newsletter focuses on some of the additional steps you can take toward general colorectal cancer prevention and good health.
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Choose alternative sources of protein (fish, poultry, legumes, soy, low-fat dairy) instead of red meat.
Researchers have found that both red meat and processed meat consumption increases colorectal cancer risk. For example, a European study followed 478,000 men and women who were cancer-free when the study began. By the end of the study, the people who ate the most red meat (at least 5 ounces per day) were about 30% more likely to develop colon cancer than were those who ate an average of less than an ounce of red meat each day. Grilling meats at high-temperatures for prolonged periods of time may increase risk even further. So if you eat red meat, do so in moderation and keep portions small. And if you like to grill occasionally, partially precook the meat first and then grill at low temperatures.
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Get enough calcium.
Calcium is important for more than strong bones. In fact, scientific research consistently shows a significant, inverse relationship between calcium intake and colorectal cancer risk. Although this relationship has not been studied specifically in people with IBD, it makes sense to make sure you are getting enough calcium. Good sources of calcium are low-fat yogurt, part-skim mozzarella cheese, skim milk, and sardines. See the table below for information about how much vitamin D you need each day.
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Get enough vitamin D.
A number of recent studies suggest that vitamin D deficiency may increase colon cancer risk. While researchers are still working to determine optimal blood levels and dietary intake recommendations, it is evident that many people in the U.S. are not getting enough of this key nutrient.
It can be difficult to meet your vitamin D needs through the foods you eat, since the best dietary sources are limited to fatty fish (e.g., salmon, tuna, and mackerel) or foods that are fortified with vitamin D (for example, milk, as well as some brands of breakfast cereals, orange juice, yogurt, margarine, and soy beverages). Smaller amounts can be found in beef liver, cheese, egg yolk, and mushrooms. Your body also makes vitamin D when your skin is exposed to the sun. But keep in mind that, when you’re inside, the sunlight reaching your skin through a window isn’t strong enough to make vitamin D. Also, if you live in the northern half of the United States, the sun isn’t strong enough for your skin to make vitamin D in the winter. See the table below for information about how much vitamin D you need each day.
When you have IBD, it may be difficult to get enough vitamin D. Checking your levels is as easy as contacting your healthcare provider for a blood test. The normal range is currently estimated to be between 30 and 74 ng/mL.
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Get enough folic acid.
Although the relationship between folic acid (a B vitamin) and colorectal cancer is less clear than the relationship between calcium and colorectal cancer, it makes sense to make sure you are meeting your folic acid needs – 400 μg/day for adults. Good sources of folic acid are leafy green vegetables (like spinach and kale), citrus fruits, and dried beans and peas. Folic acid is also added to all enriched breads, cereals, flours, corn meals, pasta, rice, and other grain products.
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Minimize alcohol intake.
Most research suggests that a high intake of alcohol increases colorectal cancer risk. For example, an analysis of more than 100 studies focusing on colorectal cancer risk factors found that, when compared with adults who were light drinkers or non-drinkers, those who averaged a drink per day or more had a 60% higher risk of colorectal cancer.
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If you smoke, quit.
Tobacco use has been consistently associated with increased colorectal cancer risk, with approximately 15% to 20% of colorectal cancers attributed to smoking. Even though nicotine has been linked to a decreased risk of developing ulcerative colitis, as well as to decreased symptoms if you already have ulcerative colitis, smoking-related risks far outweigh any benefit. If you smoke, talk to your doctor about strategies to quit, or check out the resources on the Centers for Disease Control and Prevention’s Web site.
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Maintain a healthy body weight.
Excess body weight has been linked to many diseases, and colorectal cancer is one of them, especially when the weight is concentrated around your middle. To lose weight, you must burn more calories than you consume. Slow and steady is the key – people who lose just a few pounds each week are most successful at keeping it off.
Since one pound of fat is equal to 3,500 calories, you need to reduce your intake by 500 to 1,000 calories each day lose about one to two pounds per week. Instead of fad diets or programs that you will tire of, focus on lifestyle changes that you can maintain.
If you are already at a healthy body weight and want to prevent weight gain, focus on good eating habits and regular physical activity. Remember that, as you age, your body composition will shift to less muscle and more fat, which can slow your metabolism and lead to weight gain. For more information, check out the Center for Disease Control and Prevention’s tips for losing weight or maintaining weight, or the American College of Gastroenterology’s webpage about obesity.
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Make physical activity part of your week.
People with increased levels of physical activity appear to have a decreased risk of colorectal cancer. For example, a review of 52 studies indicated that physically active individuals had 20% to 30% lower risk of colon cancer when compared to their less active peers. Even moderate levels of physical activity – like brisk walking for three to four hours per week – are associated with substantial decreases in risk.
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Take your medication.
Scientists think that long-term suppression of inflammation may stop normal cells from becoming precancerous or cancerous. Therefore, taking your IBD medication regularly, even when you are feeling well, may reduce your colorectal cancer risk. Aminosalicylates (5-ASA drugs like mesalamine, balsalazide, sulfasalzine, and olsalazine), in particular, seem to have a positive effect on risk. For example, a Mayo Clinic study found a 60% decrease in colorectal cancer risk for patients with ulcerative colitis who took mesalamine for 1 to 5 years, compared to patients who took mesalamine for less than 1 year.
If you have both ulcerative colitis and primary sclerosing cholangitis (PSC), you are at especially high risk for colorectal cancer. But the good news is that ursodeoxycholic acid (URSO), which is used to treat PSC, may decrease your risk. More research is needed to determine if URSO decreases colorectal cancer risk in IBD patients who do not have PSC.
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Conclusion
While colorectal cancer is a serious concern, especially if you have IBD, you needn’t feel powerless. Remember that your most powerful prevention tool is a colonoscopy, so be sure to follow your healthcare provider’s screening recommendations. Then, focus on the lifestyle changes you can make to reduce your risk even further.
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Dietary Recommendations for Calcium, Males and Females*