Vitamin D Comes Up Short in Cancer Study

(June 21, 2010) - Vitamin D (Read about "Vitamins & Minerals") has recently been called a super vitamin that might offer protection from all sorts of diseases, even some cancers like colorectal cancer. (Read about "Cancer: What It Is" "Colorectal Cancer")

Despite the hopes that higher blood levels of vitamin D might reduce cancer risk, a large study found no protective effect against non-Hodgkin lymphoma or cancer of the endometrium, esophagus, stomach, kidney, ovary or pancreas. (Read about "Lymphoma" "Uterine Cancer" "Esophagus Cancer" "Stomach Cancer" "Kidney Cancer" "The Ovaries" "Pancreatic Cancer") In this study, carried out by researchers from the National Cancer Institute (NCI), data based on blood samples originally drawn for 10 individual studies were combined to investigate whether people with high levels of vitamin D were less likely to develop these rarer cancers.

"We did not see lower cancer risk in persons with high vitamin D blood concentrations compared to normal concentrations for any of these cancers," said Demetrius Albanes, M.D., NCI, one of the study investigators. "And, at the other end of the vitamin D spectrum, we did not see higher cancer risk for participants with low levels."

Researchers examined vitamin D levels in blood that had been collected from over 12,000 men and women. Participants were followed for the development of cancer for up to 33 years. Investigators then compared cancer rates in participants whose levels of vitamin D in stored blood were high (above 75 nmol/L, or nanomoles per liter) or low (less than 25 nmol/L) with rates in participants whose levels of vitamin D were within the normal range (50 to 75 nmol/L).

Researchers and clinicians have looked to the possibility that vitamin D might be used for cancer prevention. Some evidence indicates that higher levels of vitamin D are associated with a lower risk of colorectal cancer, though the evidence is inconsistent.

Vitamin D is made naturally by the body when the skin is exposed to sunlight; it can also be obtained from a few foods in which it occurs naturally, from fortified foods, and from nutritional supplements. Vitamin D is essential for healthy bones, calcium absorption, and immune function. (Read about "The Immune System")