New evidence suggests spending more time in the sun could make things brighter for men with prostate cancer. Researchers have found that vitamin D can help block a protein that causes prostate cancer tumors to grow.

According to the American Cancer Society, prostate cancer is the most common type of cancer (other than skin cancer) among males in the United States. About 1 in 7 men will be diagnosed with prostate cancer during his lifetime. Prostate cancer occurs more often in African-American men, who are also more likely to be diagnosed at an advanced stage, and more than twice as likely to die from the disease. Having a family history of prostate cancer – father or brother – more than doubles a man’s risk of developing the disease.

A University of Colorado Cancer Center study recently published in the journal Prostate presents new evidence that vitamin D may help reduce cancer-causing inflammation. Scientists found that the gene GDF-15 – known to be up-regulated by vitamin D - can help block a protein which stimulates tumor growth.

“When you take vitamin D and put it on prostate cancer cells, it inhibits their growth. But it hasn’t been proven as an anti-cancer agent,” said James Lambert, lead investigator at the University of Colorado Cancer Center. “We wanted to understand what genes vitamin D is turning on or off in prostate cancer to offer new targets.”

Using a sophisticated computer algorithm, researchers analyzed samples of prostate cells and compared them to the prevalence of GDF-15 and inflammatory cells. Because they were able to demonstrate that vitamin D up-regulates the gene expression for GDF-15, they decided to further investigate to see if GDF-15 could be a pathway in which vitamin D inhibits prostate tumor growth. The results were compelling.

The study showed that gene GDF-15 blocked NFkB -- a protein which drives inflammation and encourages the growth of tumors.

“There’s been a lot of work on inhibiting NFkB,” said Lambert. “Now, from this starting point of vitamin D in prostate cancer, we’ve come a long way toward understanding how we might use GDF-15 to target NFkB, which may have implications in cancer types far beyond prostate.”

This new research suggests that using vitamin D to stimulate GDF-15 could potentially control prostate cancer in future patients.

Have you checked your vitamin D lately? If not, you may want to make an appointment with your doctor to check them with a simple blood test. Your levels should be between 30 and 80 ng/mL.

Low vitamin D levels can pose certain health risks including cancer, increased risk of death from cardiovascular disease and cognitive impairment in older adults. Therefore, make sure to spend some extra time in the sun – as that’s the best way to get vitamin D in your body. But make sure to do it safely by protecting your skin.

If you are thinking about taking a vitamin D supplement, you should be taking at least 1000-2000 IU a day, but only under the direction of your doctor. Taking too much Vitamin D can also cause toxicity.

Dr. Samadi is a board-certified urologic oncologist trained in open and traditional and laparoscopic surgery and is an expert in robotic prostate surgery. He is chairman of urology, chief of robotic surgery at Lenox Hill Hospital and professor of urology at Hofstra North Shore-LIJ School of Medicine. He is a medical correspondent for the Fox News Channel's Medical A-Team and the chief medical correspondent for am970 in New York City. Learn more at Visit Dr. Samadi's blog at Follow Dr. Samadi on Twitter and Facebook.