Scientists have determined a protein whose production is stimulated by vitamin D3 has tumor-suppressing properties.

Spanish researchers from universities in Madrid and Oviedo have built on previous research which had found evidence that the gene CST5, which is responsible for making the protein cystatin D, may be influenced by vitamin D3.

The new study set out probe that mechanism further and found that the active form of vitamin D3 directly stimulates CST5 in human colon cancer cell lines, increasing levels of cystatin D protein.
The compound was subsequently shown to inhibit the growth of human colon cancer cells in vitro and when they were transplanted into mice.

CST5 is a candidate tumor suppressor gene, the scientists concluded, and it mediates a large proportion of the anticancer effects of the active form of vitamin D3. They also add that the findings support calls for clinical trials to determine the preventive and therapeutic potential of the active form of vitamin D3 in colon cancer.

Those who would like to boost their vitamin intake may turn to nutritional supplements.