Vitamin D "may help fight cancer"Two separate studies suggest it increases survival rates
Spending too much time in the sun and on sunbeds has been implicated as a major factor in the growth of skin cancer.
But new research suggests that high levels of vitamin D – produced by the skin from sunlight – may actually help improve survival rates of people with skin cancer and bowel cancer.
But don't rush to the sunbed or throw away the sun cream just yet - there are other sources of Vitamin D and advice about exposure to the sun has not changed.
Two separate studies found that people with higher levels of vitamin D at the time they were diagnosed with either of the two cancers were more likely to survive.
Bowel cancer was the subject of the first study by scientists at the Dana-Farber Cancer Institute, Boston, which followed over 1,000 patients over 9 years. The vitamin D levels for each patient were estimated from information such as sunlight exposure, skin type, body-mass index and intake from food and supplements.
Results showed that bowel cancer patients with the higher vitamin D scores at diagnosis were 50% less likely to die from the disease compared to those with the lower scores.
Professor Kimmie Ng, study author, 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 with molecular and genetic pathways in the cell to fight cancer."
Perhaps more surprisingly, results from the second study showed that malignant melanoma patients with the lowest levels of vitamin D in their blood at the time of diagnosis were 30% more likely to relapse from the disease than those with the highest levels.
Funded by Cancer Research UK and the National Institutes of Health, the researchers from Leeds also found that patients who have higher levels of vitamin D at diagnosis have thinner tumours.
Professor Julia Newton Bishop, study author at the Leeds Institute of Molecular Medicine, said: "It's common for the general public to have low levels of vitamin D in many countries. Melanoma patients tend to avoid the sun as sunburn is known to increase the risk of melanoma. We use sunshine to make vitamin D in the skin, so melanoma patients' levels of vitamin D may be especially low.
"Our results suggest that melanoma patients may need to get vitamin D by eating fatty fish or by taking supplements to ensure they have normal levels. But we are continuing to carry out research to find out the optimum level of vitamin D."
"There's some evidence from other health studies that high levels of vitamin D are also harmful - so we should aim for a normal level rather than a very high one."
Sara Hiom, director of health information at Cancer Research UK, said: "Both these studies support the theory that higher levels of vitamin D can improve the chance of surviving cancer. The key is to get the right balance between the amount of time spent in the sun and the levels of vitamin D needed for good health."
"But protection from burning in the sun is still vital. Cancer Research UK's SunSmart campaign advises that people with lots of moles, red hair, fair skin and a family history of the disease should take extra care in the sun as they are more at risk of the most dangerous form of skin cancer. Anyone who is worried about changes in their moles should go to their GP."
The bowel cancer study was published in British Journal of Cancer and the melanoma study was published in the Journal of Clinical Oncology.
This article was published on Tue 22 September 2009
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