In the journal PLOS One, researchers from the University of California-San Diego (UCSD) School of Medicine report how they analyzed the link between Vitamin D and cancer to determine what blood level of Vitamin D was required to effectively reduce cancer risk.
The study included all invasive cancers, excluding skin cancer, Medical News Today reported.
One of the authors, Cedric Garland, adjunct professor in the UCSD School of Medicine Department of Family Medicine and Public Health, says their study is the first to put numbers on this relationship. “We have quantitated the ability of adequate amounts of Vitamin D to prevent all types of invasive cancer combined, which had been terra incognita until publication of this paper.”
The only accurate way to measure Vitamin D in the body is to measure the level of 25-hydroxyvitamin D in the blood. The kidneys convert 25-hydroxyvitamin D into the active form that helps control calcium and phosphate levels.
The median blood level of 25-hydroxyvitamin D in the participants in the clinical trial was 30 ng/ml, and in the participants in the prospective study, it was 48 ng/ml.
Researchers found that the rate of cancer incidence in the clinical study group (that had the lower median Vitamin D level) was higher than in the prospective study group. The figures were 1,020 cases per 100,000 person-years and 722 per 100,000 person-years, respectively.
They also found that cancer rates went down as 25-hydroxyvitamin D levels rose; women whose Vitamin D level was 40 ng/ml or higher had a 67% lower risk of developing cancer than women whose Vitamin D level was 20 ng/ml or lower.
But researchers did not say what the optimum intake level of Vitamin D should be - or how it should be generated, whether by greater exposure to sunlight, dietary changes or supplements.
