Vitamin D and Folate May Reduce Colon Cancer Risk

Two separate studies recently linked vitamin D and folate intake to a reduction in colorectal cancer risk.

In the vitamin D study, published in the Journal of Clinical Oncology, researchers found that people with higher blood levels of vitamin D had as much as a 33 percent reduction in colorectal cancer risk compared with those with the lowest levels. The group also found a 12 percent lower colorectal cancer risk for those with a high intake of supplemental vitamin D compared with those with the lowest intake.

While scientists are unsure about the exact connection between vitamin D and cancer, it is suggested that it may decrease the risk of cancer through cell proliferation or inhibiting angiogenesis (blood vessel growth to the tumor). The recommended daily allowance for vitamin D is 600 IU for most people, with 800 IU recommended for those above age 70. Vitamin D is found in salmon, tuna, fortified juices and milk.

The study results came from a meta-analysis that reviewed 18 studies that included over 10,000 people. Of the studies, which spanned three continents, nine looked at vitamin D intake and nine examined blood levels of vitamin D in the blood. Researchers noted this lack of uniform criteria, however, meta-analysis are used to study trends in similar data that may not been seen in a single study. They suggested the results be confirmed in large, randomized clinical trials of vitamin D supplementation.

In the folate study, published in the American Journal of Clinical Nutrition, researchers found that people with a higher folate intake per day were 30 percent less likely to get colorectal cancer than those who consumed less. For these results, researchers interviewed almost 6500 participants from the NIH-AARP Diet and Health Study who were diagnosed with colorectal cancer.

In the 1990s, folate supplementation was added to grain products in order to prevent birth defects. The recommended daily allowance of folate is 400 micrograms for most adults and 600 micrograms for pregnant women. Folate can be found in many fortified cereals as well as vegetables and beans.

The lead investigator of the study, Todd Gibson from the National Cancer Institute, told Reuters that "people don't need to change their current activities [with respect to folate]. Most people are getting what is considered an adequate amount."