Higher blood levels of vitamin D may double survival rates of colorectal cancer patients, according to a new study.

People with the highest average levels of 25-hydroxyvitamin D had a cancer-specific mortality half that of people with the lowest average levels. What’s more, high levels of the vitamin were associated with an overall mortality level 40 percent lower than people with the lowest average levels.

Knowledge of the link between vitamin D intake and protection from cancer dates from the 1940’s, when Frank Apperly demonstrated a link between latitude and deaths from cancer, and suggested that sunlight gave “a relative cancer immunity”.