Vitamin D and Cancer

UAlbany's Cancer Research Center Exterior

A significant amount of information shows that diet influences cancer risk; it is estimated that around 40 percent of human cancers are related to dietary factors. Since diet is extremely complex, the challenge for scientists is identifying the factors within a diet that are related to cancer and how these factors operate to increase or decrease the risk of disease. Since we all must eat to survive, this is a critical area of study.

Dr. JoEllen Welsh of UAlbany’s Cancer Research Center studies vitamins in relation to cancer, and is internationally recognized as an expert on nutrition and breast cancer with over 100 publications, reviews, and chapters. She has extensively studied Vitamin D and chronic disease since 1984. In addition to researching and teaching at the University at Albany, Dr. Welsh also holds the position of Chief Financial Officer for the Vitamin D Workshop, an international non-profit organization that sponsors research conferences that bring together Vitamin D researchers to communicate, share ideas, and present their work.

Vitamin D is found in a few natural foods such as fatty fish and egg yolk, but is also produced in our skin through exposure to sunlight. While Vitamin D has traditionally been known as important for bone health, further study of the compound has shown that it is important for almost every tissue in the body and may protect cells from becoming cancerous. However, the impact of Vitamin D on our health is complex as new research indicates that our genes contribute to our ability to make and utilize Vitamin D. Combining these factors— the sun, our food, supplements, and genetics— makes it difficult to determine Vitamin D’s role in combatting disease. In fact, even experts disagree about the optimum level of Vitamin D for disease prevention in humans, although studies have shown that the risk of many cancers goes down as the amount of Vitamin D in serum goes up.

“Epidemiologic studies of cancer and Vitamin D are difficult to run,” says Dr. Welsh. “It’s hard to estimate the effects and interactions of genetics, diet, and skin production. And, of course, studies that examine the development of cancer have to extend over a long time period and include many people. The incidence of cancer is only about 200 per 100,000 in the general population. For these reasons, not all studies on Vitamin D and cancer are conclusive, but the majority have found that low levels of Vitamin D increase risk of various types of cancers.”

Consistent with these population studies, “when breast cancer cells are exposed to Vitamin D in the lab, they undergo a cell death process,” says Dr. Welsh. “The Vitamin D treated cancer cells also behave differently from untreated cancer cells. Our studies suggest that Vitamin D reduces the hallmark behaviors of cancer cells, reverting them to act more like normal cells. My lab is working to identify the processes that Vitamin D triggers to alter cancer cell behavior.”

Funded since 1995 by the National Institutes of Health (NIH), Dr. Welsh has extensively characterized the impact of Vitamin D and the Vitamin D receptor, a protein found within most cells, on breast cancer development and progression. The Welsh Lab at the University at Albany includes post-doctoral fellows, graduate students, and undergraduate students completing projects related to this work. Scientists from around the world have visited the Welsh Lab to collaborate and learn techniques to study Vitamin D and cancer.

Dr. Welsh’s current five-year project funded by the NIH is studying Vitamin D and triple negative breast cancer, an aggressive subtype of the disease that is missing the three common targets for the drugs commonly used to battle other types of breast cancer. This means that there are fewer specific drugs for triple negative breast cancers, and standard treatments like radiation and chemotherapy are largely ineffective.

“Our research is studying ways to fight this kind of cancer, since it is missing the receptors that many drugs target,” says Dr. Welsh. “We have found that triple negative breast cancers retain the Vitamin D receptor, and that these cancer cells can be regulated by Vitamin D. We have identified some pathways that cause these cancers to be more aggressive, and we’ve found that Vitamin D blocks the activity of these pathways. Now we’re trying to understand the specific Vitamin D targets in these cancer cells to help optimize future treatments.”

Further studies on Vitamin D actions in the Welsh Lab could help to better understand the complex connection between Vitamin D and cancer— and provide a better understanding of how our diet and time in the sun may help us to reduce our risk of disease.