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As a practicing gastroenterologist, promoting colon health is a vital part of my professional life. There are many aspects of promoting colon health that I could address, but since March was Colon Cancer Awareness month I would like to take this opportunity to discuss preventive measures to help tackle this major disease. Colon cancer is the second leading cause of cancer-related deaths among men and women combined and the number one cause of cancer-related deaths among non-smokers. Colon cancer is also the most preventable major cancer.

Currently, colon cancer prevention focuses primarily on colonoscopy. Colonoscopy is a procedure that allows your physician to directly examine the colon (large intestine) and allows the removal of precancerous growths known as colon polyps. Colonoscopy is life-saving and it will continue to play a key role preventing and treating colon cancer. Interestingly, very little attention is given in medical circles to actually promoting colon health and preventing colon polyps.

Many of my patients ask me after I have performed their colonoscopy and removed polyps what can they do to help prevent colon polyps in the future. This fundamental question from my patients led me to look into the science behind colon cancer and colon polyp prevention. Most physicians are aware that aspirin and a class of medications known as COX-2 inhibitors can help to prevent colon polyps. While aspirin may be appropriate for some patients, it has side effects including gastrointestinal bleeding and hemorrhagic stroke, especially with long-term use. The COX-2 inhibitors have been associated with an increased risk of heart disease and they are no longer being seriously considered. I began to look into non-prescription remedies including micronutrients and antioxidants. I was quite surprised to see robust scientific evidence showing the benefit of many micronutrients and antioxidants in promoting colon health.

These micronutrients and antioxidants include beta-carotene, vitamin D, vitamin B-2, vitamin B-6, folic acid, calcium, selenium, and curcumin. These micronutrients and antioxidants have been shown in scientific studies to either prevent the occurrence of colon polyps or are associated with a decreased incidence of colon cancer.

Beta-carotene—Beta-carotene is an antioxidant. Beta-carotene supplementation has been associated with a decrease in recurrent colon polyps1. I recommend a daily intake of 8,500 IU of beta-carotene in the form of Vitamin A. Carrots are an excellent source of beta-carotene. A ½-cup of raw carrots provides 2.6 grams of fiber.

Vitamin D—Normal and cancerous cells express vitamin D receptors. The activation of vitamin D receptors induces multiple anticancer reactions including inhibiting colon cell proliferation. The intake of vitamin D was associated with a 50% lower risk of developing colorectal cancer.2 I recommend a daily intake of 1,000 IU of Vitamin D. Milk is a good source of vitamin D and calcium. An 8-ounce glass of milk contains about 125 IU (International Units) of vitamin D.

Vitamin B2—Vitamin B2 is an important cofactor in folate metabolism. High levels of vitamin B2 have been shown to protect against colon polyps.3 I recommend a daily intake of 3 mg of Vitamin B2. Almonds provide a source of vitamin B-2. A ½-cup of roasted almonds provides 6.4 grams of fiber.

Vitamin B6—Vitamin B6 prevents abnormalities in DNA synthesis, repair, and methylation. DNA methylation is important in DNA synthesis and gene stability. In an analysis of nine studies, vitamin B6 levels were associated with a decreased risk of colorectal cancer.4 I recommend a daily intake of 3 mg of Vitamin B6. Brown Rice is a good source for vitamin B-6. A ½-cup of cooked brown rice provides 1.8 grams of fiber.

Folic Acid (Folate)—Folate increases DNA methylation in colon cells which is important in DNA synthesis and gene stability. Studies have found a lower incidence of colorectal cancer among those with the highest dietary folate intake. Patients receiving folate supplementation demonstrated a significant decrease in recurrent colon polyps.5 Spinach is a great source for folate (folic acid). I recommend a daily intake of 500 mg of folate. A ½-cup of spinach provides 2.7 grams of fiber.

Calcium—Calcium appears to reduce the risk of colorectal cancer by inhibiting colon cell proliferation and also by binding bile acid and fatty acids within the colon thus reducing their tumor-inducing potential. Calcium supplementation reduces the risk of recurrent colon polyps.6 I recommend a daily intake of 800 mg of Calcium. Yogurt is a great source for calcium. Most yogurts also contain probiotics.

Selenium—Selenium protects colon cells against a wide range of external and internal stressors including inhibiting the growth of malignant colon cells and inducing their demise. Serum selenium levels were significantly lower in patient's age 60 or younger with large-size colon polyps and colorectal cancer compared to healthy controls. This strongly suggests that selenium supplementation may prevent the development of colon polyps.7 I recommend a daily intake of 100 mcg of Selenium. Corn is a good source for selenium. A ½-cup of corn provides 2.0 grams of fiber.

Curcumin—Derived from the superfood turmeric, curcumin is an antioxidant that possesses anti-cancer activity and potentiates the effect of chemotherapy in colon and other cancers.8 I recommend a daily intake of 25 mg of Curcumin. This superfood spice from South Asia is beneficial for colon health and is a likely reason for the low incidence of colon cancer in India and other South Asian countries.

To achieve optimal colon health, one can benefit by taking these micronutrients and antioxidants, especially in the dosages recommended in the research papers.

  1. John A. Baron, Bernard F. Cole, Leila Mott, Robert Haile, Maria Grau, Timothy R. Church, Gerald J. Beck, E. Robert Greenberg. Neoplastic and Antineoplastic Effects of β-Carotene on Colorectal Adenoma Recurrence: Results of a Randomized Trial. Journal of the National Cancer Institute 2003; 95: 717-722
  2. Gorham, E.D.; Garland, C.F.; Garland, F.C.; Grant, W.B.; Mohr, S.B.; Lipkin, M.; Newmark, H.L.; Giovannucci, E.; Wei, M.; Holick, M.F. Vitamin D and prevention of colorectal cancer. Journal of Steroid Biochemistry & Molecular Biology 2005; 97: 179-194
  3. Evropi Theodoratou, Susan M. Farrington, Albert Tenesa, Geraldine McNeil, Roseanne Cetnarskyj, Rebecca A. Barnetson, Mary E. Porteous, Malcolm G. Dunlop, Harry Campbell. Dietary Vitamin B6 Intake and the Risk of Colorectal Cancer. Cancer Epidemiology Biomarkers and Prevention 2008; 17: 2136-2145
  4. A. Wolk, Vitamin B6 and risk of colorectal cancer: A meta-analysis of prospective studies. Journal of the American Medical Association 2010; 303: 1077-1083
  5. Jaszewski Richard, Misra Sabeena, Tobi Martin, Ullah Nadeem, Naumoff Jo Ann, Kucuk Omer, Levi, Edi Axelrod, Bradley N, Patel Bhaumik B, Majumdar Adhip PN. Folic acid supplementation inhibits recurrence of colorectal adenomas: A randomized chemoprevention trial. World Journal of Gastroenterology 2008; 14: 4492-4498
  6. JA Baron, M Beach, JS Mandel, RU Van Stolk, RW Haile, RS Sandler. Calcium supplements for the prevention of colorectal adenomas New England Journal of Medicine 1999; 340: 101-107
  7. F Fernández-Baáares MD, E Cabrá© MD, M Esteve MD, M D Mingorance PhD, A Abad-Lacruz MD, M Lachica PhD, A Gil PhD and M A Gassull MD. Serum selenium and risk of large size colorectal adenomas in a geographical area with a low selenium status. American Journal of Gastroenterology 2002; 97: 2103-2108
  8. Jeremy James Johnson, Hasan Mukhtar. Curcumin for chemoprevention of colon cancer. Cancer Letters 2007; 255: 170-181

Frank Farrell, MD

Dr. Frank Farrell is a board certified gastroenterologist with two decades of experience. He's currently in full-time clinical practice and is the Medical Director of San Francisco Gastroenterology. He is an active staff member and is involved in the Gastroenterology Fellowship training program at California Pacific Medical Center.

Dr. Farrell received his Bachelor of Arts in Biology, Cum Laude from Seattle University, his Masters in Public Health from University of California, Berkeley, his Doctorate in Medicine from UCSF, School of Medicine, and completed his Internship, Residency, and Chief Residency in Internal Medicine at Mount Zion Medical Center in San Francisco. He completed his Fellowship in Gastroenterology at California Pacific Medical Center in San Francisco. Dr. Farrell has a special interest in colon health and screening colonoscopy.

Dr. Farrell is a member of the American Gastroenterological Association (AGA), the American College of Gastroenterology (ACG), the American Society for Gastrointestinal Endoscopy (ASGE), the California Medical Association (CMA), and the San Francisco Medical Society (SFMS). He was recognized as a Fellow of the AGA for his commitment to the field of gastroenterology and superior achievement in private practice.