Karen Collins, MS, RD, CDN
American Institute for Cancer Research
A new blood test for colon cancer risk may be on the horizon that measures levels of C-reactive protein (CRP), which is produced by the liver during periods of acute inflammation. High levels of CRP in the blood are regarded as an inflammatory marker. They are also associated with a greater risk of heart disease. A new study now links this inflammatory marker with the risk of developing colon cancer.
The study, recently published in the Journal of the American Medical Association, found that levels of CRP were significantly higher in people who developed colon cancer up to eleven years later compared to people of similar age, sex and race who remained cancer-free. If further research confirms these results, colon cancer screening recommendations could change. People with elevated CRP levels might need screening tests more often than currently suggested. Laboratory studies already show that inflammation can promote the conversion of noncancerous colon cells to cancerous forms.
If increased CRP levels correlate with greater colon cancer risk, then weight control becomes much more important. Studies have shown that overweight, not just severe obesity, raises CRP levels. Excess body fat releases substances that promote inflammation. In addition, when fat accumulates in the liver, that organ produces inflammatory substances as well. Inflammation, however, is not the only reason to avoid excess weight. Scientists already consider overweight a risk factor for colon cancer because of the elevated levels of the hormone insulin that often come with excess body fat.
Besides excess weight, the researchers in this study also confirmed a potential link between smoking and colon cancer. Both in this study and others, smokers had higher CRP levels than former smokers and those who never smoked.
A healthy diet appears to be an effective way to reduce inflammation throughout the body, thus lowering colon cancer risk. A balance of different types of fat seems to be an especially useful prevention strategy. Consuming enough omega-3 fats found in seafood and certain nuts and oils, which an American diet tends to be low in, reduces production of enzymes that stimulate inflammation. Some scientists believe that antioxidants and other substances in fruits and vegetables might help control inflammation, too.
A healthy diet that fights inflammation is the same as one that helps prevent cancer. An excellent choice is a mostly plant-based diet like the one the American Institute for Cancer Research recommends. High in fiber, this diet has healthy kinds and amounts of fat, when eaten in portions suitable for your calorie needs. Such a diet provides cancer-fighting nutrients, while it helps control weight, along with inflammation and hormones like insulin. Physical activity is another important way to fight off chronic inflammation, as well as reduce cancer risk.
Although this new study tracked individuals for 11 years, that may be too little time to establish the link between CRP and colon cancer. Scientists say colon cancer develops over a 10- to 20-year period. Consequently, it is possible that the observed higher levels of CRP are a consequence, not a cause, of early colon cancer formation. While we wait for a clearer answer, weight control, a plant-based diet, exercise and, of course, tobacco avoidance, are smart steps to safeguard your health, regardless of why they work.
The American Institute for Cancer Research (AICR) offers a Nutrition Hotline (1-800-843-8114) 9 a.m. to 5 p.m. ET Monday-Friday. This free service allows you to ask questions about diet, nutrition and cancer. A registered dietitian will return your call, usually within 48 hours. AICR is the only major cancer charity focusing exclusively on the link between diet, nutrition and cancer. The Institute provides education programs that help millions of Americans learn to make changes for lower cancer risk. AICR also supports innovative research in cancer prevention and treatment at universities, hospitals and research centers across the U.S. The Institute has provided more than $65 million in funding for research in diet, nutrition and cancer. AICRâ€™s Web address is www.aicr.org. AICR is a member of the World Cancer Research Fund International.