LONDON, August 23 (SPIS MedWire). Vitamin D may be effective in protecting people from developing cancer. Vitamin D has not been used previously in cancer prevention because the prolonged use that would be needed could lead to osteoporosis or even death. However, a research team at the Johns Hopkins University in Baltimore, USA, designed four different versions of vitamin D and tested them on mice. Dr Gary Posner reported their findings at a meeting of the American Chemical Society in Washington DC this week, on the basis of research published in the journal Carcinogenesis. Two groups of mice were tested: one that was painted with a tumour-inducing chemical and one that was not. After a 20-week treatment period one vitamin D version reduced the incidence of tumours by 28%, and the total number of tumours by 63%. Although the drug has not been tested on humans and is still in the early stages of development, Dr Posner hopes that the study could demonstrate the potential of the vitamin in preventing cancer.