Researchers from McGill University have uncovered a cellular explanation for the cancer-protective properties of vitamin D, revealing that its active form can effectively halt the growth of cancer cells. The study shows that individuals with higher levels of vitamin D in their blood tend to live significantly longer than those with lower concentrations of the vitamin.

The research team, led by professors John White and David Goltzman from the Department of Physiology, discovered that active vitamin D reduces the production and function of the cancer-promoting protein cMYC through several mechanisms. cMYC is known to promote cell proliferation and is deregulated in over 50% of all cancers. The findings were published in the Proceedings of the National Academy of Sciences on April 10, 2024.

In recent years, there has been an increasing interest in the potential role of vitamin D in promoting health and preventing disease. Previous studies have linked vitamin D deficiency to a heightened risk of various malignancies and cardiovascular diseases.

Stephen B. Kritchevsky, PhD, a professor of medicine and translational science at Wake Forest School of Medicine, highlighted a strong connection between vitamin D deficiency and these two health risks. He pointed out, “We observed vitamin D insufficiency (defined as blood levels <20 ng/ml) in one-third of our study participants. This was associated with nearly a 50% increase in the mortality rate in older adults. Our findings suggest that low levels of vitamin D may present a significant public health concern, especially for older adults in the United States.”

While vitamin D is synthesized in the skin through exposure to sunlight and can also be obtained from a few dietary sources, insufficient sun exposure and a low intake of dietary vitamin D have contributed to a global vitamin D deficiency. This deficiency is associated with an increased risk of several types of cancer, particularly cancers of the digestive system and some forms of leukemia.

"For years, my lab has been focused on studying the molecular mechanisms through which vitamin D affects human cancer cells, especially its role in inhibiting their proliferation," said Professor White. "We found that vitamin D regulates both the production rate and the breakdown of cMYC. More importantly, we discovered that vitamin D significantly stimulates the production of MXD1, a natural antagonist of cMYC, essentially shutting down its activity."

In an animal study, the researchers found that applying vitamin D to the skin of mice reduced the levels and activity of cMYC. Furthermore, mice that lacked the vitamin D receptor showed significantly higher levels of cMYC, indicating that topical vitamin D could be just as effective as oral forms in preventing cancer-related processes.

These findings underscore the significant potential of vitamin D as a preventive agent against cancer, as well as its overall importance in promoting health and preventing disease. The growing body of evidence emphasizes that ensuring adequate vitamin D levels may not only help prevent cancer but also contribute to broader public health improvements, particularly in vulnerable populations. The promise of vitamin D as a simple, accessible, and effective tool for disease prevention could revolutionize strategies for managing cancer risks worldwide.