Vit D may Take gas Pedal off Prostate Cancer

Prostate cancer appears to shrink with higher doses of vitamin D

(RxWiki News) Lately, vitamin D has been a darling natural supplement for a number of health conditions and illnesses. These findings haven't been without controversy, though. A new study looks at vitamin D and prostate cancer.

In a randomized study, higher doses of vitamin D were found to raise the levels of calcitriol, which stalled the growth of cancer cells.

"Ask your doctor if vitamin D is recommended for you."

Reinhold Vieth, Ph.D., professor at the University of Toronto in Toronto, Ontario, Canada, presented these findings at the American Association of Cancer Research (AACR) Annual Meeting 2012, held March 31-April 4.

Vitamin D has been particularly controversial when it comes to prostate cancer, with some studies suggesting that men ought to avoid higher levels of it. This new research illustrates how the vitamin affects the rate of prostate cancer growth.

"This study shows calcitriol makes the foot come off the gas pedal of cancer growth," said Vieth.

"We are not able to prove that the speed of the car has slowed down, but it certainly is a good sign,” he continued. 

Calcitriol is a hormone made from vitamin D. Higher levels of the hormone were linked with increased levels of microRNAs which inhibit prostate cancer growth.

For this study, Vieth and his team randomly assigned 66 prostate cancer patients to receive either 400, 10,000 or 40,000 IU of vitamin D for three to eight weeks before surgery to remove the prostate (prostatectomy).

Calcitriol levels in the prostate were seen to progressively increase with each daily dose of vitamin D. The dosage of 40,000 IU produced the highest levels of the hormone.

Higher levels of calcitriol were associated with lower levels of a protein that indicates prostate cancer growth, along with higher levels of microRNAs that block growth.

Researchers emphasized that they do not recommend vitamin D dosages of higher than 4,000 IU a day. The 40,000 IU dosing was assigned because of the brief time frame of the study - three to eight weeks before surgery.

Vieth explained, “Plain vitamin D provides the raw material to permit the body to take care of its own needs. We showed here that plain vitamin D allows the prostate to regulate its own level of calcitriol, and at the doses we used, for the time frame we used, it has been safe with the hoped-for desirable outcomes,” Vieth said.

“We expect that this early-phase clinical trial will open the door for more detailed clinical research into the usefulness of vitamin D in the treatment or prevention of prostate cancer,” he concluded.

dailyRx asked cancer specialist at Austin Cancer Centers, Shannon Cox, M.D., to comment on the study. "This is early research and interesting, but too early to say what it really means," Dr. Cox told dailyRx.

This research was funded by the Canadian Cancer Society in collaboration with investigators at University Health Network, Sunnybrook Hospital and Mount Sinai Hospital, all in Toronto, and at the University of Chicago.

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Review Date: 
March 30, 2012