Vitamin D Shown to Double Breast Cancer Survival Rates
Dr James Meschino DC, MS, ROHP
Many doctors and researchers are convinced that vitamin D plays an important role in preventing various cancers, including breast cancer. Over the past 20-25 years various studies have shown that women who have higher blood levels of vitamin D have an associated lower incidence of breast cancer(1,2,3). In recent years (2007) a large4-year clinical trial,involving 1179healthy postmenopausal women (over the age of 55), reported that the women given vitamin D supplementation (1100 IU per day) and calcium supplementation (1400-1500 mg per day) showed a 77% reduction in incidence of all combined invasive cancer, including breast cancer, compared to women given the placebo (4).
But what about women who have already experienced breast cancer? Can vitamin D supplementation help prevent breast cancer recurrence, progression and related fatality? A study published in March 2014 in the journal Anticancer Research has now shown that breast cancer survivors would be well advised to keep their vitamin D blood level within the ideal range. The study by B. Sharif et al showed that breast cancer patients with high levels of vitamin D in their blood were twice as likely to survive the disease compared to women with low levels of vitamin D (5).
These researchers analyzed data from five large breast cancer studies, involving a total of 4,443 breast cancer patients, with an average follow-up period of nine years. The data showed that women who had an average vitamin D blood level of 30ng/mlexperienced survival rates double that of women who had an average vitamin D blood level of 17ng/ml. The researchers pointed out that the average vitamin D blood level in patients with breast cancer in the UnitedStates is 17ng/ml (5). The form of vitamin D measured in the blood is 25-hydroxycholecalciferol.Upon ingestion of vitamin D supplements (cholecalciferol) the liver converts this form of vitamin D to 25-hydroxycholecalciferol and releases it to the blood stream. Likewise, the vitamin D made in the skin upon exposure to sunlight is also converted to 25-hydroxycholecalciferol by the liver.
In Canada blood levels of vitamin D are usually reported in nmol/L, not ng/ml. Thus, for Canadians it is worth noting that 30ng/ml is equal to about 75nmol/L, whereas 17ng/ml is equal to about 42nmol/L. In their concluding statements B. Sharif et al suggest that breast cancer patients may be well advised to increase their blood level of vitamin D to 80ng/ml (approximately 200nmol/L), based on all available evidence (5).
How Does Vitamin D Prevent Breast Cancer
Vitamin D has been shown to reduce cancer development and progression in a number of ways. Vitamin D slows down the rate of cell division, which reduces the likelihood that cancerous mutations will emerge. Vitamin D promotes maturation (differentiation) of newly formed cells, which reduces transformation to a cancerous state. Vitamin D favourably modulates the function of immune cells, many of which are responsible for identifying and destroying emerging cancer cells (1,2,3,4,5).
In addition, vitamin D is responsible for increasing the cell’s production of a surface receptor (antennae) known as E-cadherin, which enables the cell to bind to and communicate with adjacent cells or supporting tissues. Very aggressive cancer cells tend to have low levels of E-cadherin, which enables them to replicate unchecked by adjacent cells, giving themselves the green light to invade adjacent tissues and spread into the blood and lymphatic system in their quest to metastasis throughout the body(6,7,8).
Studies show that many cancer cells maintain vitamin D receptors on their cell surface. When vitamin D (25-hydroxycholecalciferol D) attaches to this receptor it stimulates the synthesis of E-cadherin, which in turn puts the brakes on the ability of cancer cells to invade adjacent tissues and metastasize. (5,6) B. Sharif and fellow researchers suggest that it is the expression of E-cadherin by cancer cells that likely explains why breast cancer patients with higher blood levels of vitamin D are less likely to have further progression of their disease after standard medical treatment(6).
In a follow-up interview regarding the study (March 2014), coauthor Dr. Cedric F. Garland, professor in the Department of Family and Preventive Medicine at the University of California, San Diego School of Medicine, pointed out that “a 2011 meta-analysis by Garland and colleagues estimated that a serum vitamin D blood level of 50 ng/ml (about 125 nmol/L) is associated with a 50percent lower risk of breast cancer. “While there are some variations in absorption, those who consume 4,000IU per day of vitamin D from food or a supplement normally would reach a serum level of 50ng/ml. Garland urged patients to ask their health care provider to measure their levels before substantially increasingvitamin D intake”(9).
Vitamin D toxicity is not known to occur until reaching a vitamin D blood level at or above 100 ng/ml (250nmol/L), so there is a large margin of safety when taking vitamin D supplements (3).
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- Vieth R. Vitamin D and cancer mini-symposium: the risk of additional vitamin D. Ann Epidemiol 19: 441-445, 2009.
- Lappe JM,Travers-Gustafson D, Davies KM, Recker RR, Heaney RP. Vitamin D and calcium supplementation reduces cancer risk: results of a randomized trial. Am J Clin Nutr 85: 1586-1591, 2007.
- Sharif B. Mohr, Edward D. Gorham, June Kim, Heather Hofflich And Cedric F. Garland. Meta-analysis of vitamin D sufficiency for improving survival of patients with breast cancer. Anticancer Research34(3):1163-1166,2014
- Pena C, Garcia JM, Silva V, Rodriguez R, Alonso et al. E-cadherin and vitamin D receptor regulation and SNAIL and ZEB1 in colon cancer: clinicopathological correlations. Hum Mol Genet 14(22):3361-70, 2005
- G Berx, et al. E-cadherin inactivation in lobular carcinoma in situ of the breast.EMBO J.14(24): 6107–6115, 1995.
- G Berx, et al. E-cadherin is inactivated in a majority of invasive human lobular breast cancers by truncation mutations throughout its extracellular domain. Oncogene13(9): 1919–1925, 1996.
- Science Daily: Vitamin D increases breast cancer patient survival study show. March 6, 2014. http://www.sciencedaily.com/releases/2014/03/140306163236.htm