Clinical Study on Vitamin D Reducing Breast Cancer

A Georgetown University clinical study has added to the already impressive number of studies showing that higher vitamin D blood levels reduce a woman's risk of breast cancer by as much as 85 percent, and the new study is getting media attention.

"The results of the experiment , conducted at the Georgetown University Medical Center in Washington and released this week at the annual meeting of the American Association for Cancer Research, bolster the striking finding from the field of human epidemiology that women with low levels of vitamin D tend to have a higher risk of breast cancer, while those with more of the sunshine vitamin get less of the cancer," The Toronto Globe and Mail's Martin Mittelstaedt reported recently. "The new study found that mice with mammary cancers sensitive to estrogen, the most common type in women, had a twofold reduction in tumour incidence and a fourfold reduction the growth of their cancers if given vitamin D."

More than a dozen case-control studies have already suggested that low vitamin D levels are strongly connected with higher breast cancer risk. Lab studies have shown how the active form of vitamin D can inhibit the growth and spread of cancer cells. But this clinical study adds further weight to the argument.

According to the Globe and Mail, "Two major human trials are currently underway in the US. One at Creighton University in Omaha, the other a combined effort at Harvard Medical School and Brigham and Women's Hospital in Boston - using higher doses of vitamin D. The trials may be able to shed more light on its use as a possible cancer treatment and appropriate doses, although it is expected to be years before either reports results."

New Study Shows Less Cancer with More Sun

Women who used sunbeds more than once a month for several decades had a 37 percent lower risk of contracting breast cancer, according to a new prospective study of nearly 50,000 Swedish women followed for 15 years. A strong addition to data suggesting that the benefits of regular UV exposure from any source outweigh the manageable risks of overexposure.

Researchers at the University of Oxford in England, the University of Oslo in Norway, The Karolinska Institute in Sweden and the Harvard School of Public Health in the United States published the study online  recently in the peer reviewed journal Cancer Epidemiology, Biomarkers and Prevention. The study shows that women who spent more than one week per year on sunbathing vacations between ages 10-29 had a 30 percent lower overall risk of any internal cancer and 44 percent fewer breast cancers compared to non-tanning women.

"UV exposure earlier in life was related to reduced overall and breast cancer risk," the authors reported. "Further research is needed to define the amount of solar or artificial UV exposure that many, or may not, be beneficial for cancer prevention."

While the data did not suggest that cumulative UV exposure was protective, the authors believe that the vitamin D pathway inherent with UV exposure is the likely mechanism responsible for cancer risk reduction for those who sought sunlight or sunbeds.