Life Extension Magazine®

Vitamin D can Reduce Breast Cancer Risk

A study in the British Journal of Cancer found that the risk of death from breast cancer was 42% lower in women with high vitamin D levels, compared to those with low levels.

Scientifically reviewed by: Dr Gary Gonzalez, MD, in July 2021. Written by: Paz Etcheverry, MS, PHD.

A meta-analysis published in 2021 found that low vitamin D levels are prevalent among newly diagnosed breast cancer patients.1

Woman enjoying the sun and absorbing vitamin d

The authors noted that vitamin D insufficiency/deficiency may be linked with breast cancer initiation or progression.

One reason is that vitamin D regulates genes in cancer cells, inhibiting their growth and disabling their ability to survive. 1,2

For women already suffering from breast cancer, vitamin D may improve survival, reduce recurrence, and reduce all-cause mortality.3-5

An analysis published in the British Journal of Cancer found that the risk of death from breast cancer was 42% lower in women with high vitamin D levels, compared to those with low levels.6

The medical community is increasingly recognizing that vitamin D can help protect against breast and other cancers.

Risks of Low Vitamin D

Low levels of vitamin D are associated with many different problems, including brittle bones, increased cardiovascular disorders, and cognitive decline.7-10

Studies around the globe have associated a link between low vitamin D levels and increased risks of different types of cancer, including colon, ovarian, prostate, and breast cancers.

In Pakistan, for example, metastatic breast cancer was more prevalent in women with vitamin D deficiency than in those with slightly better vitamin D status.11

In a mainly Hispanic population, a high prevalence of vitamin D insufficiency (less than 30 ng/mL) and deficiency (less than 20 ng/mL) was found among breast cancer patients.12

Similar findings have been reported in women from other countries, including Brazil,13 Sudan,14 and China.15

How Vitamin D Protects Against Cancer

Doctor examining breast scan of woman

There is evidence that vitamin D helps protect against breast cancer in three different ways.

1. Vitamin D regulates genes in cancer cells.

The active form of vitamin D exerts its effects in the body by first binding to vitamin D receptors on the nucleus of cells. These receptors are also present in tumor cells.

Once it binds to these receptors, vitamin D regulates several dozen genes and pathways that inhibit the growth and lead to apoptosis (programmed death) of cancer cells.1,2

2. Vitamin D quenches inflammation by inhibiting the synthesis of inflammatory compounds.16

For example, vitamin D reduces the formation of pro-inflammatory prostaglandins that are associated with breast cancer development. It does this by decreasing their production and enhancing their degradation.5

Vitamin D also decreases levels of nuclear factor-kappa B (NF-kB) and tumor necrosis alpha (TNF), which have been linked to breast cancer formation and growth.17-20

Researcher dividing samples for studying immune systems

3.Vitamin D supports immune function.

Vitamin D receptors are distributed throughout many tissues and organs, including the immune system (thymus, B and T lymphocytes, and bone marrow).21

The activity of various defense and immune cells, including antigen-presenting cells, macrophages, monocytes, and activated CD4 T cells is modulated by vitamin D.21

Experimental studies have demonstrated that the active forms of vitamin D (calcitriol) and its analogs can inhibit proliferation and induce apoptosis in various cancer cell types.22

Fighting Existing Breast Cancer

Woman with breast cancer supplementing with vitamin d

Vitamin D can also help patients who already have breast cancer.23-26

In a study that followed a group of women previously treated for breast cancer, those with the highest blood levels of vitamin D were 28% less likely to have died during the eight-year follow-up period than women with the lowest levels.26

A meta-analysis found that, in women whose 25-hydroxyvitamin D levels were 9.3 ng/mL or higher, every 4 ng/mL increase in vitamin D level decreased the risk of breast cancer death by 6%.25

Aromatase inhibitor drugs like letrozole or anastrozole are commonly used in breast cancer treatment. These medications may cause side effects in bones or muscles. These symptoms are worse for women with low vitamin D levels, and supplementation may help mitigate these.27-29


Two woman wearing pink ribbons who are survivors

Low blood levels of vitamin D are associated with increased rates of breast cancer.

Vitamin D may exert its protective effects by regulating genes in cancer cells, quenching inflammation, and suppressing the levels and activity of estrogen.

In women who have already been diagnosed with this disease, vitamin D intake increases survival rates, and has been found to reduce pain associated with aromatase inhibitor treatment.

Life Extension® recommends that readers consider daily doses in the range of 3,000 IU to 8,000 IU for overall health.

Blood tests for 25-hydroxyvitamin D enable precise individual dosing of vitamin D supplements.

If you have any questions on the scientific content of this article, please call a Life Extension® Wellness Specialist at 1-866-864-3027.


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  2. Radom A, Wedrychowicz A, Pieczarkowski S, et al. Effect of Selected Factors on the Serum 25(OH)D Concentration in Women Treated for Breast Cancer. Nutrients. 2021 Feb 9;13(2):564.
  3. Madden JM, Leacy FP, Zgaga L, et al. Fitting Marginal Structural and G-Estimation Models Under Complex Treatment Patterns: Investigating the Association Between De Novo Vitamin D Supplement Use After Breast Cancer Diagnosis and All-Cause Mortality Using Linked Pharmacy Claim and Registry Data. Am J Epidemiol. 2020 Mar 2;189(3):224-34.
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  30. Available at: Accessed August 2, 2021.