From the Guidelines
Vitamin D helps with breast cancer by stimulating apoptosis and differentiation, inhibiting angiogenesis and proliferation in tumor cells, and reducing inflammation, with optimal levels of 25(OH)D above 20 ng/mL associated with lower breast cancer risk. The mechanism by which vitamin D exerts its effects on breast cancer involves binding to vitamin D receptors in breast tissue, regulating cell growth, promoting cell differentiation, and triggering apoptosis in abnormal cells 1. Some key points about the relationship between vitamin D and breast cancer include:
- Numerous association studies suggest that serum 25(OH)D levels are inversely associated with the risk of many types of cancer, including breast cancer 1
- A meta-analysis of available studies indicated that there is a trend for lower incidence of breast cancer with 25(OH)D levels above 20 ng/mL 1
- Analysis of 2 studies with 880 cases and 880 controls demonstrated that individuals with serum 25(OH)D of approximately 52 ng/mL had 50% lower risk of breast cancer than those with levels below 13 ng/mL 1
- A large case-control study on 1,394 post-menopausal breast cancer patients and 1,365 controls confirmed that the 25(OH)D level was significantly associated with lower breast cancer risk, particularly at levels above 20 ng/mL 1
- While no specific vitamin D regimen has been definitively proven to prevent or treat breast cancer, maintaining adequate vitamin D levels through sensible sun exposure, diet, and supplements may be beneficial 1. The optimal level of 25(OH)D for breast cancer prevention is not well established, but levels above 20 ng/mL are associated with lower risk, and some studies suggest that levels above 30-50 ng/mL may be even more beneficial 1. Overall, the evidence suggests that vitamin D plays a supportive role in breast cancer prevention and potentially in improving outcomes for breast cancer patients, and maintaining adequate vitamin D levels is a reasonable approach for individuals at risk of breast cancer 1.
From the Research
Mechanism of Vitamin D in Breast Cancer
- Vitamin D has been reported to have anticancer activities against many cancer types, including breast cancer 2.
- The mechanism by which vitamin D influences the natural history of cancer includes induction of apoptosis, stimulation of cell differentiation, anti-inflammatory and antiproliferative effects, and inhibition of angiogenesis, invasion, and metastasis 3.
- Vitamin D regulates the phenotype of human breast cancer cells by changing the cytoarchitecture of actin filaments and microtubules, inducing filopodia and lamellipodia, and promoting cell-to-cell contacts via large cytoplasmic extensions 4.
- Vitamin D also affects the expression of various proteins, including claudin-7, occludin, E-cadherin, N-cadherin, and P-cadherin, which are involved in cell adhesion and migration 4.
Biological Mechanisms and Risk Factors
- Vitamin D deficiency is a significant public health issue closely linked to numerous diseases, including breast cancer 5.
- Serum levels of vitamin D ≥ 40.26 ng/mL ± 14.19 ng/mL could exert a protective effect against breast cancer 5.
- Biological mechanisms, such as those related to the immune system, and risk factors like diet are implicated in the relationship between vitamin D and breast cancer 5.
- Proper serum levels of vitamin D may have a protective effect against breast cancer, and dietary supplementation may be an appropriate procedure to achieve these optimal vitamin D concentrations 5.
Current Evidence and Research
- Preclinical and ecologic studies have suggested a role for vitamin D in breast cancer prevention 2.
- Inverse associations have been shown between serum 25-hydroxyvitamin D level and breast cancer development, risk for breast cancer recurrence, and mortality in women with early-stage breast cancer 2.
- Clinical trials of vitamin D supplementation have yielded inconsistent results 2.
- Ongoing research is being conducted to clarify the true role of vitamin D in the onset of breast cancer and evolution of the disease after treatment 3.