New York, March 23 (IANS): Taking vitamin D supplements could slow or even reverse the progression of less aggressive, or low-grade, prostate tumours without the need for surgery or radiation, new research has found.

"We do not know yet whether vitamin D treats or prevents prostate cancer," said Bruce Hollis from the Medical University of South Carolina.

"At the minimum, what it may do is keep lower-grade prostate cancers from going ballistic," Hollis noted.

The findings were presented at the 249th National Meeting & Exposition of the American Chemical Society (ACS), the world's largest scientific society, in Denver, US.

In cases of low-grade prostate cancer, many urologists do not treat the disease, but instead do what's called "active surveillance," Hollis explained.

As a man must wait 60 days from the time of his biopsy before he can undergo a prostatectomy, so that inflammation from the biopsy can subside, Hollis wondered if giving these men vitamin D supplements during the 60-day waiting period would affect their prostate cancer.

In a new randomised, controlled clinical trial, his team assigned 37 men undergoing elective prostatectomies either to a group that received 4,000 unit of vitamin D per day, or to a placebo group that did not receive vitamin D.

The men's prostate glands were removed and examined 60 days later.

Preliminary results from this study indicated that many of the men who received vitamin D showed improvements in their prostate tumours, whereas the tumours in the placebo group either stayed the same or got worse.

Also, vitamin D caused dramatic changes in the expression levels of many cell lipids and proteins, particularly those involved in inflammation.

"Cancer is associated with inflammation, especially in the prostate gland," Hollis noted.

"Vitamin D is really fighting this inflammation within the gland," Hollis added.