Cancer
Study explains why vitamin D prevents prostate cancer
By David Liu, Ph. D.
May 18, 2008 - 9:20:41 AM

SUNDAY May 18, 2008 (foodconsumer.org) -- A study by researchers at the University of Rochester Medical Center provides an explanation why vitamin D may prevent prostate cancer and maybe other types of cancer.

Many epidemiologic and laboratory studies have showed that vitamin D may protect against many types of cancer including prostate cancer and it may be used both as a preventative and a therapeutic agent. The Canadian Cancer Society has already recommended daily use of 1,000 IU of vitamin D to prevent cancer.  

The study published in the June 15, 2008 issue of the International Journal of Cancer found vitamin D acts on a gene known as G6PD and increases production of an enzyme called glucose-6-phosphate dehydrogenase.

This enzyme is known to clear cells of reactive oxygen species (ROS), molecules of peroxide or so called free radicals , which can be produced by exposure to some chemicals or forms of radiation and damage DNA, ultimately leading to development of cancer.
"Many epidemiological studies have suggested the beneficial properties of vitamin D," said Yi-Fen Lee, associate professor of urology at the Medical Center who led the research.

"Our findings reflect what we see in those studies and demonstrate that vitamin D not only can be used as a therapy for prostate cancer, it can prevent prostate cancer from happening."

The vitamin used in the study was 1, 25-hydroxylvitamin D3, the most potent and active form of vitamin D in the human body.  Both normal cells and prostate cancer cells were used in the study.

The researchers also found that vitamin D does not have the similar activity in prostate cancer cells.  “Vitamin D does not protect cancer cells from injury or damage, which is good,” Lee said.

"Our study adds one more beneficial effect of taking a vitamin D supplement. Taking a supplement is especially important for senior citizens and others who might have less circulation of vitamin D, and for people who live and work areas where there is less sunshine."

Vitamin D is photosynthesized in humans by exposure of the skin to sunlight.  This vitamin can also be obtained from supplements or a limited number of vitamin D containing foods such as oily fish, egg yolk and fortified foods.

It has been known that up to 10,000 IU a day of this vitamin is safe to use.  Experts believe that current recommended daily allowance is way too low. Presently, it is recommended that adults aged 19 to 50 have intake of 200 IU per day, according to Linus Pauling Institute.