Umbrella Review on the Relationship Between Vitamin D Intake and Cancer.

Cancer is a major public health problem and the second leading cause of mortality in the European Union. Vitamin D deficiency has been linked to cancer via several pathways. However, umbrella reviews on the extra-skeletal effects of vitamin D have largely overlooked its connection to cancer. This review presents an overview of the relationship between vitamin D intake (nutritional and/or supplementation) and five major types of cancer (breast, colorectal, lung, pancreatic, and prostate cancer). The findings indicate that vitamin D intake may have a preventive effect on breast, colorectal, and lung cancer and may reduce colorectal cancer mortality. However, results for other cancers were inconsistent, and no data were available on the impact of vitamin D intake on pancreatic and lung cancer mortality. While there is some evidence suggesting potential benefits of vitamin D intake, most reviews are based on observational studies, limiting conclusions about causality. Additionally, methodological challenges related to vitamin D metabolism and study designs contribute to the inconclusive nature of the data. Further research is needed to clarify the role of vitamin D intake in cancer prevention and management.