Does vitamin D protect against cancer?

The sun’s ultraviolet (UV) radiation is both the major cause of skin cancer and the best source of vitamin D. In Australia we need to balance the risk of skin cancer from too much sun exposure with the need to maintain adequate vitamin D levels. The importance of vitamin D to good health has long been recognised, especially in relation to bone and musculoskeletal health. However there isn’t sufficient evidence to suggest that vitamin D may protect against certain cancers.

When the UV Index is 3 or above, the majority of people can maintain adequate vitamin D levels from just a few minutes of sun exposure, such as walking from the office to get lunch. Sensible sun protection when UV is 3 or above does not put people at risk of vitamin D deficiency and prolonged sun exposure does not cause your vitamin D levels to increase further, but does increase your risk of skin cancer.

When UV levels are below 3, sun protection is not generally required. In late autumn and winter in some southern parts of Australia (for instance Hobart and Adelaide), where the UV level stays below 3, we recommend spending time outdoors in the middle of the day. Being physically active e.g. gardening or going for a brisk walk, also helps boost vitamin D levels. Some foods, such as oily fish and eggs, also contain small amounts of vitamin D, while margarine and some types of milk have added vitamin D. However it is difficult to get enough from diet alone. If you are concerned about vitamin D deficiency, consult your GP.