Vitamin D Breast and Cancer Risk

Vitamin D Breast and Cancer Risk


Question:

Is there a relationship between vitamin D status and risk of breast cancer?

Answer:

Vitamin D is essential for many processes in the body.  Bone health, immune function, reduction of inflammatory processes and variation of cell growth are among the many roles of vitamin D in the body. An excellent resource on vitamin D facts can be found online at the Office of Dietary Supplements.

Vitamin D status is assessed through a blood test called 25-hydroxy vitamin D. The shortened name is 25(OH)D. This is the blood test researchers use to determine vitamin D status for subjects in studies of the relationship between vitamin D and cancer.

Early studies suggest vitamin D deficiency might increase risk for breast cancer. Further research has been carried out in a number of countries involving thousands of subjects. The results of these studies have been mixed.

The majority conclude a significant role for vitamin D in breast cancer prevention could not be established for premenopausal breast cancer, though some studies have shown postmenopausal breast cancer risk to be reduced when vitamin D levels are at or above established normal ranges prior to cancer diagnosis. The table below gives a summary of results from two large, well-respected research projects on vitamin D and occurrence of breast cancer.

One is the EPIC study – the European Prospective Investigation of Cancer and Nutrition study. The other is a meta-analysis of nine studies that looked at vitamin D blood levels and cases of breast cancer. A meta-analysis is a way to combine results from several studies on the same topic. This approach allows for larger numbers of people to be studied together, and typically, more study subjects makes for a stronger study.

Vit D status and cancer incidence by subgroup: 
 

Vit D status and  cancer  incidence by  subgroup:

EPIC study

Meta-analysis of 9 studies

Premenopausal

No relationship between  vitamin D blood levels and  breast cancer risk

No relationship between vitamin D blood levels and breast  cancer risk

Postmenopausal with hormone replacement therapy (HRT)

Higher vitamin D blood levels were linked with lower cancer risk

Postmenopausal women (both those using and not using  hormone therapy) had reduced risk of breast cancer if their  vitamin D blood levels were 27 ng/mL or more.  Risk was even lower for women with blood levels up to 35 ng/mL.  No additional benefit (reduction in risk) for women with vitamin D blood levels above 35 ng/mL.

Postmenopausal without hormone replacement therapy (HRT)

 

In summary, these studies suggest that for postmenopausal women in particular, it seems that having enough vitamin D to keep blood levels in a healthy range—a minimum blood level of 27 ng/mL (67 nmol/L)—is important for good health and cancer risk reduction. Your dietitian or doctor can help you determine how much vitamin D you may need to supplement to reach this goal.

Vitamin D Supplementation for Breast Cancer Survivors

There are some studies on vitamin D supplementation and breast cancer recurrence. These studies did not look directly at vitamin D levels in the blood, but instead had women report their use of vitamin D supplements. For breast cancer survivors, Vitamin D supplementation was associated with decreased risk of recurrence among estrogen receptor positive (ER+), but not estrogen receptor negative (ER-) tumors in the Harvard breast cancer pooling project.

Breast cancer patients receiving medications to lower estrogen levels especially need to have vitamin D levels monitored. These women also should ensure they get enough calcium and vitamin D to maintain bone density. And some research shows that breast cancer survivors may be at higher than average risk for vitamin D deficiency and insufficiency. Ask your medical team about checking your vitamin D levels, and supplementing if necessary.

Also, researchers have discovered that for some women who are experiencing joint pain and fatigue due to aromatase inhibitors—medications that lower estrogen levels—supplementing vitamin D can help lessen these unpleasant side effects.

Finally, keep in mind that some women are at higher risk of vitamin D deficiency due to other factors, such as a darker skin color, which blocks some of the sun's rays and limits the creation of vitamin D in the skin. Women who are older, or who live in northern areas also may need more vitamin D from diet or supplements to stay healthy.

To summarize, at this point, we don't know if taking vitamin D supplements will decrease breast cancer risk, or the risk of getting the disease again in women who've already had it. However, vitamin D is an essential nutrient. You need to take steps to ensure you get enough vitamin D for good health, especially bone health. Studies are ongoing and these should help us better understand the relationship between vitamin D nutrition and breast cancer prevention and recurrence.

The original question and answer were generously donated by Diana Dyer, MS, RD a cancer survivor, registered dietitian, organic garlic farmer, and the author of "A Dietitian's Cancer Story: Information & Inspiration for Recovery & Healing from a 3-time Cancer Survivor.

Question and Answer updated by JoAn Muncie, MS, RD, LD on behalf of the ON DPG

References

  1. Kühn T, Kaaks R, Becker S, Eomois PP, Clavel-Chapelon F, Kvaskoff M, … Linseisen J. Plasma 25-hydroxyvitamin D and the risk of breast cancer in the European prospective investigation into cancer and nutrition: a nested case-control study. Int J Cancer. 2013;133(7):1689-700.
  2. Bauer SR, Hankinson SE, Bertone-Johnson ER, Ding EL Plasma vitamin D levels, menopause, and risk of breast cancer: dose-response meta-analysis of prospective studies. Medicine (Baltimore). 2013;92(3):123-31.
  3. Poole EM, Shu X, Caan BJ, Flatt SW, Holmes MD, Lu W, Kwan ML, Nechuta SJ, Pierce JP, Chen WY. Postdiagnosis supplement use and breast cancer prognosis in the After Breast Cancer Pooling Project. Breast Cancer Res Treat. 2013;139(2):529-37.
  4. Office of Dietary Supplements, National Institutes of Health. Dietary Supplement Fact Sheet: Vitamin D. Available at: http://ods.od.nih.gov/factsheets/vitamind-healthprofessional/
  5. Prieto-Alhambra D, Servitja S, Javaid MK, Garrigós L, Arden NK, Cooper C, Albanell J, Tusquets I, Diez-Perez A, Nogues X. Vitamin D threshold to prevent aromatase inhibitor-related bone loss: the B-ABLE prospective cohort study. Breast Cancer Res Treat. 2012;133(3):1159-67.
  6. Friedman CF, DeMichele A, Su HI, Feng R, Kapoor S, Desai K, Mao JJ. Vitamin d deficiency in postmenopausal breast cancer survivors. J Womens Health (Larchmt). 2012;21(4):456-62.
  7. Khan QJ, Reddy PS, Kimler BF, Sharma P, Baxa SE, O'Dea AP, Klemp JR, Fabian CJ. Effect of vitamin D supplementation on serum 25-hydroxy vitamin D levels, joint pain, and fatigue in women starting adjuvant letrozole treatment for breast cancer. Breast Cancer Res Treat. 2010;119(1):111-8.

Page updated: January 2014