Vitamin D has no effect on Overall Cancer Death Risk

A new US study has concluded that Vitamin D has no effect on the overall risk of dying from cancer although higher levels of the vitamin may be linked with a decreased risk of dying from colorectal cancer. This finding contradicts the findings of some other studies.

The study is published in the early online issue of the Journal of the National Cancer Institute and is the work of Dr. D. Michal Freedman, of the National Cancer Institute in Bethesda, Maryland, and colleagues.

The researchers wrote that:

"To our knowledge, this study is the first to examine the relationship between measured serum vitamin D levels and cancer mortality for selected site and for all sites combined."

Diet and exposure to sunlight are the main source of vitamin D in the body. Some epidemiological studies have suggested there is a link between higher levels of vitamin D and increased survival or reduced risk of dying from cancer. Also studies on animal and human cells have suggested the vitamin shrinks tumors and triggers the death of cancer cells.

Freedman and colleagues analyzed data on 16,818 people who took part in the third national Health and Nutrition Examination Survey. The participants were aged 17 or older and were followed from between 1988 and 1994 up to 2000. Levels of Vitamin D, or more specifically serum 25(OH)D, circulating in the blood at time of enrollment (baseline) were measured using a process known as radioimmunoassay. Levels of vitamin A were also measured for comparison.

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