One of the most preventable forms of cancer, colorectal tumors strike more than one million people annually, killing 500,000 every year. The good news is that simple lifestyle changes can prevent up to half of these cases—and the latest screenings (like virtual colonoscopy) make it easier and less invasive to look for these tumors before they become malignant.
Who’s at Risk?
Genes and gender can influence an individual’s likelihood of developing colorectal cancer. Approximately 15 percent of people who develop this cancer have familial risk factors, and between 3 to 5 percent have an inherited susceptibility. Anyone whose immediate family members had colorectal cancer or polyps before age 60 needs regular screenings.
Some research suggests that Jews of Eastern European descent (Ashkenazi Jews) have the highest colorectal cancer risk of any ethnic group. In this country, African Americans have the highest incidence rates of this cancer (52 cases per 100,000 people), as well as mortality rates. By contrast, native Africans—a continent away—have much lower rates of colorectal cancer (less than five cases per 100,000). This difference seems to underscore how important a role diet and other environmental factors play in colorectal cancer.
Gender can also influence who develops this cancer—and when. For example, the total intake of calories, selenium, and fiber plays a stronger role in colorectal cancer development for American men than women, while vitamin D is a more important factor for females. In general, men are more likely to develop this cancer, though diet and lifestyle may play a role. For example, one Singapore study finds that women tend to have precancerous tumors removed—and are more careful to avoid controllable risk factors than men.
What You Can Control
Here are 10 steps we can all take—regardless of our genes or gender—to lessen the risk of colorectal cancer.
1 Watch your weight. Since the 1990s, excess body weight has been linked to colon (and other) cancers, especially if you gain around your waist. “Body fatness directly affects levels of many circulating hormones, such as insulin, insulin-like growth factors, and estrogens, creating an environment that encourages carcinogenesis [cancer development] and discourages apoptosis [natural cell death],” notes the American Institute for Cancer Research (AICR) in a chapter on colorectal cancer in its recent global report. Every added inch of waist circumference increases the risk of colorectal cancer by 5 percent. The good news is that every inch you lose around your middle also lowers your risk.
2 Limit how much you eat. Did you realize that one serving of protein is the size of a computer mouse or deck of cards? (For more on portion sizes, go to www.tasteforlife.com.) To eat less, serve meals on a lunch or salad plate instead of a large dinner plate. When you dine out, order an appetizer portion of an entree with a small salad. Never rely on size names (“medium” may be a far larger portion than you want); look for ounces instead, remembering that 16 ounces equals one pound. Never eat too much just because you paid for it! Bring the remainder home to enjoy for another meal.
Counting calories? One small banana, one medium pear, three plums, 14 almonds, half of a medium apple with two teaspoons of peanut butter, and a half-cup of plain nonfat yogurt with a half-cup of sliced berries all add up to about 100 calories.
3 Cut out sugar and refined carbs. High intakes of simple sugars (fructose and sucrose) appear to increase the risk of colorectal cancer in some studies. Animal research links sugar intake with precursors of colon cancer, as well. Obviously, sugar and refined foods contain less nutrients and fiber than most whole foods. Who needs empty calories?
4 Enjoy a plant-based diet. Approximately four billion people worldwide build their meals around foods that are grown, rather than animals that need to be raised. The Mediterranean diet has been linked to lower risk of colorectal cancer recurrence in women, while even a prudent western diet (rich in produce, low-fat dairy, fish, lean poultry, and whole grains) seems to protect against a number of cancers, including colorectal. One reason may well be that foods lower down the food chain tend to contain fewer synthetic hormones and persistent toxic herbicides and pesticides.
5 Reduce meat consumption. “Weight-promoting drugs are also used [in livestock production], especially in beef,” adds Elson M. Haas, MD, while certified organic meat is raised without these dangerous substances. Red and processed meats have repeatedly been linked to colorectal cancer, so Walter C. Willett, professor of medicine at Harvard Medical School, advises eating less than 18 ounces a week. Instead, consume more vegetable protein (like legumes) and omega-3-rich fish and seafood. One recent meta-analysis shows that fish consumption may reduce the risk of colorectal cancer by 12 percent.
6 Up your fruit and vegetable intake. “Eating more plant foods increases intake of a number of healthful bioactive food components,” like antioxidants and phytochemicals, “along with more dietary fiber,” says John Milner, PhD, at the National Cancer Institute. AICR recommends increasing your consumption of nonstarchy (low-glycemic) produce.
“Diets rich in fruit and deep-yellow vegetables, dark-green vegetables, and onions and garlic” have been linked to lower incidences of colorectal adenoma, a cancer precursor, find researchers at the University of Buffalo. Several studies link greater intake of garlic with lower risk of colorectal cancer. And recent investigations in Canada associate eating cruciferous (cabbage-family) vegetables with lower risk of rectal cancer in women.
7 Take your supplements. In general, women who take their multivitamin/mineral are less likely to develop this cancer. “Multivitamin and mineral supplements can complement a healthy diet,” write Ontario researchers in a recent review of scientific studies. Low levels of folate, riboflavin, and vitamins B6 and B12 have been linked to DNA damage and increased risk for colorectal cancers, so make sure your daily multi includes a complete B complex. The Journal of the National Cancer Institute reports an inverse relationship between vitamin D levels and colorectal cancer mortality, and experts have recently recommended increasing the daily allowance for this vitamin. European research with a proprietary fermented wheat germ extract (Avemar) finds it to be promising support during treatment, appearing to increase the likelihood of surviving colorectal cancer.
Spices can help, too. Research linking Cox-2 inhibitors with colorectal cancer prevention makes curcumin, the yellow pigment in turmeric (a spice in curry), a promising supplement. “Curcumin protects against the disease before, during, and after exposure to carcinogens,” says Michael Murray, ND. “In addition to inhibiting prostaglandin formation, curcumin also exhibits potent antioxidant effects (in some experimental studies it was found to be up to 300 times more potent than vitamin E).”
8 Befriend beneficial bacteria. “Health-promoting bacteria, such as lactobacillus, bifidobacteria, and propionibacter species, increase your body’s ability to produce substances that protect you against colon cancer,” adds Dr. Murray. “These include short-chain fatty acids (SCFA), such as acetic, proprionic, and butyric acid. When it comes to these compounds, the more the merrier,” he explains. For optimal protection, friendly flora operate best with low to moderate meat consumption and plenty of dietary fiber.
9 Drink smart. Watch your alcohol consumption. The European Prospective Investigation into Cancer (EPIC) study links drinking alcohol with higher colon and rectal cancer risk. Instead, sip green tea—rich in antioxidant, anticancer, and anti-inflammatory substances. A recent study of almost 75,000 women 40 to 70 years of age suggests regular consumption of this tea may reduce the risk of colorectal cancer, independent of contributing factors like waist-to-hip ratio or red meat consumption.
10 Exercise regularly. Moderate activity, at least 30 minutes a day, helps prevent a number of cancers. More than a dozen studies link lack of exercise with colon cancer, and the Health Professional Follow-up Study performed on men shows that working out regularly cuts colon cancer risk in half. One year-long study finds exercise promotes apoptosis of colon crypts in both men and women.