The optimal concentration of 25(OH)D for CRC risk reduction is 75–100 nmol/l, which is higher than the current Institute of Medicine (IOM) recommendations.32 This finding suggests that low VDR expression may reduce the risk of CRC by increasing the levels of vitamin D. Notably, vitamin D3 supplementation has not been found to significantly reduce the incidence of aggressive tumors. This evidence concerns the gene VDR and colorectal carcinoma.