Vitamin D helps patients with advanced colon cancer improve their response to chemotherapy and targeted anti-cancer drugs, according to a new report. 

A team of researchers measured the vitamin D content in the blood levels of 1,043 patients enrolled in a phase 3 clinical trial. The trial compared three first-line treatments for newly diagnosed, advanced colon cancer. All three of the treatments involved chemotherapy combined with the targeted anti-cancer drugs bevacizumab and/or cetuximab, reported CBS News.

Vitamin D, often called the "sunshine vitamin," is absorbed by people with sun exposure, although it's also available in some foods and supplemental forms. The vitamin is involved with regulating the levels of minerals - such as phosphorous and calcium - in the body. 

The study found a link between vitamin D intake and colon cancer survival rates, but it did not provide an explanation as to why it helps. 

Dr. Len Lichtenfeld, deputy chief medical officer for the American Cancer Society, told CBS News that researchers have been investigating vitamin D as a potential anti-cancer tool for years, though none of the findings have been strong enough to warrant a recommendation.

"Everyone comes to the same conclusion -- yes, there may be some benefit, but we really need to study it carefully so we can be certain there aren't other factors that make vitamin D look better than it is," Lichtenfeld said. "These findings are interesting, and show that vitamin D may have a role in improving outcomes in cancer care." 

This study was the most solid evidence in science so far that suggests that vitamin D could make a difference in colon cancer, Dr. Smitha Krishnamurthi, an associate professor of hematology and oncology at Case Western Reserve University School of Medicine in Cleveland, told CBS News.

Krishnamurthi added that she doesn't recommend colon cancer patients with normal vitamin D levels to take supplements until it's tested in a clinical trial. 

The study is scheduled for presentation this week at the Gastrointestinal Cancers Symposium in San Francisco.