The Impact of Vitamin D and Its Dietary Supplementation in Breast Cancer Prevention: An Integrative Review

Abstract

Vitamin D deficiency is currently a significant public health issue closely linked to numerous diseases, such as breast cancer. This study aims to determine the estimated optimal serum levels of vitamin D to have a protective effect against breast cancer, in addition to exploring the biological mechanisms and risk factors involved. A literature search of articles published in the last 5 years was conducted, and simple statistical analyses using mean and standard deviation were performed to calculate the average concentration of vitamin D from different available studies. It has been observed that serum levels of vitamin D ≥ 40.26 ng/mL ± 14.19 ng/mL could exert a protective effect against breast cancer. Additionally, various biological mechanisms, such as those related to the immune system, and risk factors like diet implicated in this relationship were elucidated. Consequently, it can be concluded that 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.

Keywords: breast cancer; mechanism of action; optimal levels; prevention; risk factors; vitamin D.

Figure 1

Scheme of the synthesis process of 1,25(OH)2D through ultraviolet-B (UVB) radiation and diet, divided into two stages: in the liver, vitamin D is converted to 25-hydroxyvitamin D by the action of 25-hydroxylases, and subsequently in the kidney, it is converted to 1,25-dihydroxyvitamin D by the action of 1-α hydroxylase.

Figure 2

PRISMA flow diagram representing the study selection process [31].

Figure 3

Representation of some of the different mechanisms of action involved in the relationship between vitamin D and breast cancer addressed in this study. (A) Representation of the vitamin D/VDR axis. (B) Representation of the regulation of genes related to breast cancer. (C) Representation of the mechanisms involved with the immune system. Abbreviations: VDR, vitamin D receptor; RXR, retinoid X receptor; VDRE, vitamin D response element; RNA Pol II, RNA Polymerase II; CYP24A1, Cytochrome P450 Family 24 Subfamily A Member 1; CYP27B1, Cytochrome P450 Family 27 Subfamily B Member 1; lncRNA, long non-coding RNA; MEG3, maternally expressed gene 3; Ca⁺², calcium; TNF-α, tumor necrosis factor-alpha; NF-κB, nuclear factor kappa B; T CD8+, CD8 T lymphocytes.

Figure 4

Representation of some of the factors influencing the relationship between vitamin D and breast cancer in the context of disease prevention mentioned in this study.