Vitamin D is "a really interesting little molecule"

Beth Jacobs, PhD
Beth Jacobs, PhD

Beth Jacobs, PhD, thinks a key to cancer prevention may be found in a tiny molecule that our own bodies produce.

Beth Jacobs, PhD, studies genetic, dietary and lifestyle factors associated with cancer risk, and she’s at the forefront of an international scientific movement focusing on vitamin D.

It’s been long known that a vitamin D deficiency can lead to loss of bone mineralization and, in extreme cases, rickets and adult osteomalacia (bone weakness). However, the link between vitamin D deficiency and various diseases - cancer, heart disease and diabetes – is now a hot topic of study. There’s even preliminary research into whether low vitamin D levels are related to influenza, said Jacobs, an Arizona Cancer Center researcher and assistant professor at the University of Arizona Mel and Enid Zuckerman College of Public Health.

“I just think it’s a really interesting little molecule because you make it yourself,” she explained. “It’s different from the usual nutrients we study.”

While vitamin D is found in some foods, most people’s bodies can make all the vitamin D they need just by having their skin exposed to sunlight. When UV-B rays hit the skin, a reaction takes place that enables skin cells to produce vitamin D, which is actually a hormone.
“It’s a controversial area,” Jacobs said. “As you know, we’re supposed to limit our sun exposure. But certain people, no matter how much vitamin D they consume, they can’t get their levels up. There are several genetic factors in pathways that are related to vitamin D metabolism – how much vitamin D is available for tissue.”

Additional sun exposure could be the answer for these people, but acknowledging that current skin cancer prevention guidelines don’t work for everyone is a slippery slope, she said. She plans to write a grant to work with the Arizona Cancer Center’s Skin Cancer Institute on new, modified guidelines for sun exposure.

Jacobs, who has a master’s degree in foods and nutrition from Purdue University and a doctoral degree in nutritional sciences from the University of Arizona, has also been studying the role of vitamin D in breast and colon cancer. The National Cancer Institute-funded projects she has worked on have had striking results.

Her preliminary findings indicate that higher blood vitamin D levels are associated with a lower risk of colorectal adenoma recurrence. Moreover, she and Elizabeth Hibler, a UA doctoral student, have found that circulating blood vitamin D levels are linked to genetic factors. Jacobs has studies planned with her colleague Peter Jurutka, PhD, of the University of Arizona College of Medicine Phoenix in partnership with Arizona State University, to determine how genetic variation affects the function of enzymes related to vitamin D metabolism. Additionally, preliminary results from a study with Cancer Center colleague Cyndi Thomson, PhD, and collaborators at the University of California, San Diego, suggest that higher dietary intake of vitamin D leads to lower chances of breast cancer recurrence.

While the results are impressive, Jacobs acknowledges that in the past scientists have found what appears to be a wonder drug only to have its efficacy fail for one reason or another in subsequent trials. Still, Jacobs believes that vitamin D’s special properties give it real potential for widespread benefits.

“It would be terrific if vitamin D research shows we could prevent cancer recurrence or increase quality of life if we could get people’s vitamin D level up,” she said.

More promising studies like Jacobs’ may lead scientists to go further and ask whether increasing people’s vitamin D levels can lead to preventing cancer from occurring in the first place.

“Right now, that’s looking possible,” Jacobs said. “That’s a definite hypothesis.”

“That,” she added, “would be awesome.”