Women with breast cancer who take the 'sunshine' vitamin D supplement are twice as likely to survive the disease as women low in the nutrient.
The vitamin-which we also get from sunshine-blocks tumour growth by improving communication between healthy cells.
Taking 4,000 IUs of vitamin D supplements every day should be enough to protect the breast cancer sufferer and prevent the disease becoming a killer, say researchers at the University of California, San Diego school of medicine. This is far above the recommended daily allowance (RDA), however, which is set at just 600 IUs and 800 IUs for people over the age of 70.
The evidence for high levels of vitamin D and breast cancer survival is so overwhelming that the researchers stopped their study early, and have recommended that the supplement should be part of the therapy.
They made their discovery when they reanalysed the evidence from five studies that involved 4,443 breast cancer patients. The women with 30 nanograms of vitamin D per millilitre of blood serum (ng/ml) were twice as likely to survive their breast cancer as those with just 17 ng/ml, which is the average level of vitamin D blood serum in the US.
It also works as a preventative. Women who had 50 ng/ml levels of the vitamin in their blood serum also had a 50 per cent lower risk of developing the cancer.
(Source: Anticancer Research, March 2014)