HIGH levels of vitamin D in the body may improve survival rates in cancer patients.
Two new studies say that people with more vitamin D - which is produced by the skin in sunlight - when diagnosed with bowel or skin cancer were more likely to survive.
Vitamin D deficiency has also been linked to reducing the risk of multiple sclerosis.
In the first study, a team from the Dana-Farber Cancer Institute in Boston followed more than 1,000 bowel cancer patients for about nine years.
Researchers estimated the vitamin D in their blood at the time of diagnosis, and found those with higher levels were 50 per cent less likely to die from the disease.
Professor Kimmie Ng, author of the study said: "Our study shows that levels of vitamin D after colorectal cancer diagnosis may be important for survival.
"We are now planning further research in patients with bowel cancer to see if vitamin D has the same effect, and to investigate how vitamin D works."
The second study, funded by Cancer Research UK looked at patients with malignant melanoma - the most deadly skin cancer, and linked low levels of vitamin D with higher rates of relapse. High levels of the vitamin were linked to thinner tumours.
Lead author Professor Julia Newton Bishop said: "It's common for the general public to have low levels of vitamin D in many countries."