Vitamin D and Colorectal Cancer By: Samia B.

Vitamin D  A fat soluble vitamin stored in the body’s fatty tissue, precursors to hormones  D2 and D3 important forms to humans made by plants and made in the body when exposed to sunlight respectively  Helps the body absorb calcium from small intestine— important for normal bone formation  Helps improve muscle strength and immune function  Helps reduce inflammation  Helps maintain adequate blood levels of calcium and phosphate important for bone health "Vitamin D: MedlinePlus Medical Encyclopedia." U.S National Library of Medicine. U.S. National Library of Medicine, n.d. Web. "Vitamin D and Cancer Prevention: Strengths and Limits of the Evidence." National Cancer Institute. National Institutes of Health, n.d. Web..

Vitamin D  Source: Most received from sunlight—few foods like fish, fish oil and eggs  Recommended intake: *2005 Dietary Guidelines for Americans recommends extra dose for older Americans, people with dark skin and people who do not receive sufficient sunlight "Vitamin D and Cancer Prevention: Strengths and Limits of the Evidence." National Cancer Institute. National Institutes of Health, n.d. Web..

Vitamin D  Deficiency can lead to osteoporosis or rickets in children.  If taking supplement, recommended dose in children < 1 years old take 1,000 IU daily or adults take 2,000 IU daily  Overconsumption of Vitamin D is associated with increased calcium deposits in kidney, heart, and lungs, heart rhythm abnormalities, confusion, fever, chills, vomiting, and weight loss.  High Vitamin D possibly associated with other cancers (ie: pancreatic cancer) "Vitamin D." — Health Professional Fact Sheet. N.p., n.d. Web..

Colorectal Cancer  A cancer that starts in either the colon or rectum  In 2009,136,717 people in the United States were diagnosed --70,223 men and 66,494 women  In 2009, incidence higher in blacks than White, Hispanics, Asians, American Indian/Alaska Native  Colon is made up of many layers-cancers starts in the inner tissues and spreads outward  May start as a polyp-tissue growth that starts at the lining and may go into the center of the colon or rectum.  95% of colon and rectal cancers are adinocarcinomas-cancers that start in the cells that line the inside of the colon or rectum.  In 2009, 51,848 people in the United States died from colorectal cancer-26,806 men and 25,042 women. "Colorectal Cancer Overview." What Is Cancer? N.p., n.d. Web.. "Basic Information About Colorectal Cancer." Centers for Disease Control and Prevention. Centers for Disease Control and Prevention, 26 Feb Web..

Vitamin D and Colorectal Cancer Link  Rationale: Vitamin D is thought to regulate gene expression, induce differentiation, sensitize cells to apoptosis and inhibits the proliferation of cultured human colon carcinoma cells.  Decreased formation of tumor in rats Vitamin D and colon cancer. Fábio Pereira, María Jesús Larriba, Alberto Muñoz. Instituto de Investigaciones Biomédicas Alberto Sols, Consejo Superior de Investigaciones Científicas - Universidad Autónoma de Madrid, Arturo Duperier 4, Madrid, Spain.

American Cancer Society’s Cancer Prevention Study (CPS) II Nutrition Cohort  Diet, history and lifestyle of more than 12,000 men and women were analyzed  Men who had higher intakes (>525 IU Vitamin D) per day had slightly lower risk of colorectal cancer than those who had lower intakes  No change noticed in women Calle, E. E., Rodriguez, C., Jacobs, E. J., Almon, M. L., Chao, A., McCullough, M. L., Feigelson, H. S. and Thun, M. J. (2002), The American Cancer Society Cancer Prevention Study II Nutrition Cohort. Cancer, 94: 2490–2501. doi: /cncr

Colorectal Cancer Risk and Dietary Intake of Calcium, Vitamin D, and Dairy Products: A Meta-Analysis of 26,335 Cases From 60 Observational Studies  Meta-analysis performed to evaluate this relationship in observational studies.  Data from 60 epidemiological studies enrolling 26,335 CRC cases were pooled  Vitamin D was associated with a non-significant 6% reduction in CRC risk. Huncharek M., Muscat J., Kupelnick B. Colorectal cancer risk and dietary intake of calcium, vitamin D, and dairy products: A meta-analysis of 26,335 cases from 60 observational studies. Nutr. Cancer. 2009;61:47–69. doi: /

Third National Health and Nutrition Examination Survey  Epidemiolgic study  16,818 participants  Those with higher vitamin D blood levels (≥80 nmol/L) had a 72% lower risk of colorectal cancer death than those with lower vitamin D blood levels (< 50 nmol/L) The Third National Health and Nutrition Examination Survey (NHANES III)

Women's Health Initiative study  Randomized control trial format  36,000 menopausal women  2 groups: Vitamin D + calcium, placebo  Cancer risk was not lower in the group that took vitamin D.  *Weak study  Dose given (400 IU) may have been too low  Most of the women already had high Vitamin D levels at initiation of the study  Women had the option to take extra Vitamin D/Calcium if they wished Wactawski-Wende J, Kotchen JM, Anderson GL, Assaf AR, Brunner RL, Langer RD, Lasser NL, Lewis CE, Limacher MC, Manson JE; Women's Health Initiative Investigators. Calcium plus vitamin D supplementation and the risk of colorectal cancer. N Engl J Med. 2006;354:

National Cancer Institute Statement  “Although some evidence suggests that vitamin D may provide some protection against colorectal and possibly other cancers, the evidence of potential benefit is limited and inconsistent. Moreover, some studies have suggested the possibility that higher vitamin D levels are associated with increased risk for some cancers, including pancreatic cancer.”  “The National Cancer Institute (NCI) does not recommend for or against the use of vitamin D supplements to reduce the risk of colorectal or any other type of cancer.” "Vitamin D and Cancer Prevention: Strengths and Limits of the Evidence." National Cancer Institute. National Institutes of Health, n.d. Web..

American Cancer Society Statement  “Some studies suggest that risk of developing certain types of cancer is lower for people who have higher levels of vitamin D in their bodies. There are also studies that suggest higher vitamin D levels might be linked to greater risk of other cancers. More studies are needed to find out whether vitamin D is the reason for the differences in risk, or if there is another reason.” "Vitamin D." Vitamin D. N.p., n.d. Web..

Conclusion  There is no substantial evidence to support that an increase in Vitamin D levels is associated with a decreased risk in colorectal cancer  Patients with low Vitamin D levels should be on a supplement. Otherwise, it may not be a bad idea for a patient to take Vitamin D via a supplement or multivitamin as long as it is within a reasonable intake.  Patients with already high Vitamin D levels should refrain from taking any additional supplements as it is unknown the risks associated with overconsumption.