Higher levels of Vitamin D in the blood may be linked to a lower risk of developing certain cancers, a study in Japanese adults reported yesterday.
"These findings support the hypothesis that Vitamin D has protective effects against cancers at many sites," researchers reported in a study published in The BMJ medical journal.
Vitamin D is made by the skin in response to sunlight. By maintaining calcium levels in the body, it helps keep bones, teeth and muscles healthy.
While the benefits of Vitamin D on bone health are well known, there is some evidence that it may protect against chronic diseases as well, including some cancers.
Studies to date, however, have been carried out mainly in European and North American people.
As natural Vitamin D concentrations can vary by ethnicity, researchers from half-a-dozen Japanese medical schools and institutes set out to determine the potential for lowering cancer risk in Asians.
They analysed the public health records of 33,736 men and women aged 40 to 69.
After adjusting for well-known cancer risk factors -- age, weight, smoking, and alcohol intake, for example -- the researchers found that, overall, higher Vitamin D levels was associated with a 20 percent lower cancer risk for both genders.
The risk of liver cancer dropped even more, by up to 50 percent, especially for men.
Previous studies have shown that low levels of Vitamin D increase the risk of bone fractures, heart disease, colorectal cancer, diabetes, depression, Alzheimer's disease and death.
But others have found no evidence of a link to disease risk.