Vitamin D’s Role in Colorectal Cancer Prevention, Immune Health

Once known mainly for its role in bone health, vitamin D is now recognized as a powerful immune system modulator with the potential to prevent colorectal cancer (CRC), according to a study published in Nutrients.1 Acting through receptors on immune cells, vitamin D influences key processes like inflammation, T-cell activation, and tumor suppression.

Emerging research highlights how vitamin D boosts immunity and reduces colorectal cancer (CRC) risk by regulating inflammation and cell growth. | Image credit: Galina Zhigalova - stock.adobe.com

“This review aims to investigate the physiological functions and anti-cancer effects of vitamin D, with a particular focus on its role in CRC,” wrote the researchers of the study. “In addition, we explore the prevalence of vitamin D deficiency and summarize clinical trials evaluating the impact of vitamin D supplementation on CRC outcomes, providing an analysis of the latest research findings.”

Vitamin D is a vital nutrient that supports numerous functions in the body, most notably bone development and maintenance.2 It also plays important roles in the nervous, musculoskeletal, and immune systems. The body can produce vitamin D through sun exposure, but factors like age, skin tone, and geographic location can limit this natural synthesis. Additionally, vitamin D can be obtained through certain foods and dietary supplements. Despite these multiple sources, vitamin D deficiency remains a widespread global issue.

For this review, the researchers collected evidence from a range of peer-reviewed studies, including randomized controlled trials, observational cohort studies, and mechanistic research exploring the relationship between vitamin D and CRC.1 Studies were identified through systematic searches of databases such as PubMed and Scopus using keywords including “vitamin D,” “colorectal cancer,” “immune modulation,” and “supplementation.” Inclusion criteria focused on studies that investigated the immunological mechanisms of vitamin D in CRC prevention, as well as clinical outcomes related to vitamin D status or supplementation.

Additionally, the researchers included data on study design, population characteristics, vitamin D dosages, outcome measures, and relevance to immune-related pathways. Findings were then analyzed to identify consistent patterns and gaps in the current evidence base, with a focus on insights that could inform clinical practice.

The findings consistently demonstrated that vitamin D plays a pivotal role in modulating immune responses relevant to CRC prevention and progression. Clinical trials and observational studies showed that higher serum levels of vitamin D are associated with a reduced risk of CRC incidence and improved survival outcomes in diagnosed patients.

Mechanistic studies revealed that vitamin D, through its interaction with vitamin D receptors on immune cells, enhances T-cell function, regulates cytokine production, and suppresses pro-inflammatory pathways—factors closely linked to tumor development and progression. Additionally, vitamin D was found to influence gene expression involved in cell proliferation, apoptosis, and angiogenesis, effectively limiting cancer cell survival and metastasis.

Furthermore, supplementation trials indicated that maintaining optimal vitamin D levels may lower inflammation markers and improve immune surveillance in high-risk populations.

However, the researchers noted some limitations. Variability in study designs, dosages, and population demographics highlights the need for further large-scale, standardized research to confirm these benefits and establish clinical guidelines.

“In summary, vitamin D plays a crucial role in both CRC prevention and treatment. It influences cancer cell proliferation, inflammation, cell death mechanisms, and the activity of the Sirtuin protein family,” wrote the researchers. “Recent research highlights that maintaining optimal vitamin D levels can help reduce CRC risk and improve treatment outcomes. However, further studies are needed to elucidate the precise mechanisms of action and optimize the therapeutic application of vitamin D in CRC management.”

References

1. Fekete M, Lehoczki A, Szappanos Á, et al. Vitamin D and colorectal cancer prevention: Immunological mechanisms, inflammatory pathways, and nutritional implications. Nutrients. 2025; 17(8):1351. https://doi.org/10.3390/nu17081351

2. Vitamin D deficiency. Cleveland Clinic. August 2, 2022. Accessed April 22, 2025. https://my.clevelandclinic.org/health/diseases/15050-vitamin-d-vitamin-d-deficiency