According to American Cancer Society 2014 estimates, over 230,000 men will be diagnosed for the first time with prostate cancer, while nearly 30,000 will die from it. That makes prostate cancer the second most common cancer and one of the leading causes of cancer deaths among all U.S. men.

Fortunately, new research suggests men at high risk of developing prostate cancer might benefit from increased blood levels of vitamin D3.

Scientists have already shown vitamin D3 to be critical for the development and growth of normal cells, but what wasn’t clear yet is the role it plays in cancer. So, assistant professor of urology Dr. Adam B. Murphy led a team of researchers at Northwestern University as well as the University of Illinois at Chicago (UIC) to determine what impact if any vitamin D levels would have on the initiation or spread of prostate cancer.

For the study, Murphy’s team recruited nearly 700 men, aged 40-79 and of diverse ethnic background, who were receiving their first prostate biopsy after registering abnormal test results for blood levels of prostate-specific antigen (PSA) or from a digital rectal examination (DRE). Once enrolled, researchers measured the participants’ blood serum levels of 25-hydroxyvitamin D, or 25(OH)D. While vitamin D levels considered normal range from 30 to 80 nanograms per milliliter (ng/ml), most of the recruits registered a vitamin D deficiency of under 20 ng/ml, and were subsequently divided into four groups: those with less than 12 ng/ml, less than 16 ng/ml, less than 20 ng/ml, and less than 30 ng/ml.

After four years of collecting and analyzing data, researchers discovered that lower vitamin D levels seemed to predict prostate cancer risk. This was especially true for African-American and European-American men.

In fact, for the group with 25(OH)D levels lower than 12 ng/ml, European-American men were over 3-1/2 times and African-American men were nearly 5 times more likely to develop aggressive prostate cancer. Additionally, African-American men with 25(OH)D levels less than 20 ng/ml were still nearly 2-1/2 times more likely to be diagnosed with prostate cancer.

“In our study, vitamin D deficiency seemed to be a predictor of aggressive forms of prostate cancer diagnosis in European-American and African-American men,” said Murphy, who co-authored the study. “Vitamin D supplementation may be a relevant strategy for preventing prostate cancer incidence and/or tumor progression in prostate cancer patients.”

The study, published in the journal Clinical Cancer Research, suggests men of all races have their vitamin D levels checked at least once a year. And we agree. Of course, you can get vitamin D3 naturally by spending adequate time outdoors in the sun