Vitamin D Key Player in Colorectal Cancer Prevention Through Immune Regulation and Inflammation Control, Review Reveals

However, the researchers stress the need for large-scale trials to determine optimal vitamin D dosages and to better understand the underlying mechanisms. Given the widespread vitamin D deficiency, particularly in areas with limited sunlight, increasing intake through vitamin D-rich foods or supplements could be a beneficial strategy to reduce CRC risk.

Vitamin D, synthesized in the skin through UV-B exposure, plays a vital role in calcium and phosphorus homeostasis. Beyond this, it modulates the immune system, reduces inflammation, induces apoptosis, and supports anti-angiogenesis. Available in two forms—D3 (from animal sources) and D2 (from plants)—D3 is more potent. The active form, 1,25-dihydroxyvitamin D, regulates key physiological processes and has anti-inflammatory and anti-carcinogenic effects, making it essential in preventing diseases like colorectal cancer.

Mónika Fekete and colleagues from the Institute of Preventive Medicine and Public Health, Semmelweis University, Budapest, Hungary, explored the physiological functions and anti-cancer properties of vitamin D, particularly in CRC. Their review also addresses the global prevalence of vitamin D deficiency and evaluates clinical trials assessing the impact of vitamin D supplementation on CRC outcomes.

In the review, researchers sifted through over 10,000 studies on colorectal cancer and vitamin D, narrowing it down to 50 after filtering out duplicates and irrelevant studies. The selected studies involved adult human participants with colorectal cancer, its precursors, or vitamin D deficiency, and those who received vitamin D supplementation.

Key Highlights:

• Vitamin D supports various bodily functions, including nerve cell communication, blood pressure regulation, and prevention of respiratory infections.
• It is important in maintaining gut health, thyroid hormone levels, blood sugar regulation, and mitigating aging effects.
• Vitamin D acts as an antioxidant, reducing inflammation, suppressing autoimmune responses, and supporting immune cell function.
• Previous research highlighted vitamin D’s ability to inhibit uncontrolled cell growth, angiogenesis (new blood vessel formation), and promote apoptosis in abnormal cells.
• Vitamin D deficiency is strongly linked to an increased risk of colorectal cancer, as it exacerbates intestinal inflammation, promoting cancer progression.
• A meta-analysis of 31 studies found that those with the highest vitamin D intake (80 ng/mL) had a 25% reduced risk of colorectal cancer compared to those with the lowest intake (10 ng/mL).
• The Nurses’ Health Study showed that women with the highest vitamin D intake had a 58% reduced risk of colorectal cancer compared to those with the lowest intake.
• The Iowa Women’s Health Study found that high calcium and vitamin D intake reduced colorectal cancer risk by about 50%.
• The Spanish PREDIMED study and studies using vitamin D supplementation showed similar protective effects.
• Vitamin D supplementation reduced the likelihood of polyp development by 33% and the risk of high-risk adenomatous polyps by 43%, according to a Canadian study.
• Vitamin D is crucial in preventing and treating colorectal cancer by reducing inflammation, regulating immune responses, promoting cancer cell death, and inhibiting tumor growth.
• For individuals with colorectal cancer, vitamin D may improve survival rates and reduce mortality.

Overall, the findings emphasize vitamin D’s vital role in preventing and treating colorectal cancer by influencing cancer cell proliferation, inflammation, and apoptosis, as well as the activity of the Sirtuin protein family.

"While recent studies highlight the importance of maintaining optimal vitamin D levels to reduce CRC risk and improve treatment outcomes, they also reveal limitations, such as the inability to define the exact mechanisms of vitamin D's protective effects," the authors stated. They concluded, "This emphasizes the need for more large-scale randomized clinical trials to determine optimal dosages and formulations for therapeutic use."

Reference:

Fekete, M., Lehoczki, A., Szappanos, Á., Zábó, V., Kaposvári, C., Horváth, A., Farkas, Á., Major, D., Lipécz, Á., Csípő, T., & Varga, J. T. (2024). Vitamin D and Colorectal Cancer Prevention: Immunological Mechanisms, Inflammatory Pathways, and Nutritional Implications. Nutrients, 17(8), 1351. https://doi.org/10.3390/nu17081351