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Pancreatic Cancer & Vitamin D Deficiency

Jul 10, 2011 | By Krithika Subramanian, Ph.D.
Pancreatic Cancer & Vitamin D Deficiency
Photo Credit Polka Dot Images/Polka Dot/Getty Images

Pancreatic cancer is one of the leading causes of cancer deaths in the United States. The overall survival rate for pancreatic cancer is low, at 4 percent. According to the National Cancer Institute, there has been little improvement in pancreatic cancer incidence and survival rates, probably due to the advanced stage of diagnosis typical for pancreatic cancer and a lack of effective screening methods. The high mortality rate, limited treatment options and poor treatment responses have prompted interest in factors that provide protection against pancreatic cancer. A large number of scientific studies have examined the potential of vitamin D in providing protection against many cancers, including pancreatic cancer.

Vitamin D Basics

Vitamin D, or the "sunshine vitamin," is technically a pro-hormone -- a precursor for a hormone. Two forms of vitamin D are relevant to human health: vitamin D2, or ergocalciferol, found in plant sources, and vitamin D3, or cholecalciferol, synthesized in skin upon exposure to ultraviolet-B rays in sunlight and found in some dietary sources, such as fish liver oil and eggs. For most people, sunlight exposure is the major source, accounting for over 90 percent of their vitamin D levels. Calcitriol, the biologically active and potent form of vitamin D, is made by modification of both D2 and D3 forms in the liver and kidneys.

Mechanism of Action

Inside cells there is a protein called Vitamin D Receptor -- or VDR. Vitamin D, in the form of calcitriol, is bound by VDR, and this vitamin-protein complex cooperates with other proteins to turn genes on and off. The alterations in the function of genes ultimately regulate important processes throughout the body, including calcium absorption, improvements in immune function, and muscle strength and reduction of inflammation. VDR is found in over 30 tissue types in the human body, including pancreatic islet cells -- the region of the pancreas responsible for producing and secreting the hormone insulin.

Cancer Prevention Potential

Early clues to the anti-cancer potential of vitamin D stemmed from observations linking sun exposure to reduced cancer risk and mortality. Studies on cultured cancer cells and animal models of cancer, summarized recently in "Cancer Journal," show that vitamin D can halt the growth and even promote death of many types of cancer cells, including pancreatic cancer cells. Vitamin D also inhibits tumor invasiveness and angiogenesis -- the formation of blood vessels -- in rodent tumor models of cancers. Population-based studies in humans have yielded mixed results, according to the National Cancer Institute. While some studies show an association between higher vitamin D levels and intake and lower risk of colorectal, breast, prostate and pancreatic cancer, others have not.

Pancreatic Cancer Studies

The role of vitamin D deficiency in pancreatic cancer is still unclear. A study in over 120,000 people, published in "Cancer Epidemiology, Biomarkers and Prevention" in 2006, found that higher dietary intake of vitamin D was associated with progressively lower pancreatic cancer risk. In contrast, a study of Finnish male smokers, published in "Cancer Research" in 2006, found that participants with higher vitamin D levels in blood were at increased risk for pancreatic cancer. One consideration confounding this study is that tobacco smokers are an established high-risk pancreatic cancer group. Further scientific investigations are required to unravel the factors contributing to benefits and harms of vitamin D in pancreatic cancer. Consult your doctor about vitamin D concerns specific to your health.

References

Article reviewed by Christine Brncik Last updated on: Jul 10, 2011

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