ABC News reported on Good Morning America on Monday that higher levels of vitamin D shrink cancer cells much the same way as the uber-drug Tamoxifen — a realization that comes as no surprise to vitamin D researchers, but which is starting to resonate in the lay press.

“What happens is that vitamin D enters the cells and it triggers the cell death process,” Dr. JoEllen Welsh, a researcher at the State University of New York, told ABC’s Good Morning America. “It’s similar to what we see when we treat cells with [breast cancer treatment drug] Tamoxifen.”

Welsh’s ongoing research involves treating breast cancer cells with the active form of vitamin D.

“The vitamin’s effects were even more dramatic on breast cancer cells injected into mice,” ABC reported. “After several weeks of treatment, the cancer tumors in the mice shrank by an average of more than 50 percent. Some tumors actually disappeared. Similar results have been achieved on colon and prostate cancer tumors in mice.”

Vitamin D’s role in regulating cell growth has been well-established in research, and thousands of studies now link low vitamin D levels with higher rates of most forms of cancer.

UV exposure to the skin is the body’s main source of vitamin D. Sun avoidance in the past generation has led to higher vitamin D deficiency rates in most of the world.

To read the ABC story click here.