Vitamin D helps prevent breast cancer

Health conscious readers may already know that, in many cases breast cancer can be prevented by simply following a healthy diet and lifestyle. Remember that breast cancer screening encouraged by many breast cancer organizations like Susan G. Komen for the Cure is intended to detect the disease early and it does not help prevent the disease from developing in the first place.

New studies have recently yielded more evidence suggesting that maintaining sufficient levels of serum vitamin D is preventative against breast cancer, a disease expected to be diagnosed in one in eight women in the United States in their lifetime.

Yin L and colleagues from the German Cancer Research Center in Heidelberg, Germany conducted a meta-analysis of epidemiological studies on the association between serum vitamin D and the risk of breast cancer; simply put, they found that deficient concentrations of the vitamin in the blood was linked to a higher risk of the disease.

For the study, Yin and colleagues identified ten relevant studies on the association between serum 25-hydroxyvitamin D (25(OH)D) and breast cancer incidence or mortality from patient information published until Sep 2009 by major medicine databases.

An increase of 25(OH)D by 20 ng/mL was found associated with a 41 percent, 8 percent and 27 percent reduction in the breast cancer risk in case-control studies, nested case-control studies and both study designs combined, respectively.

The findings were published in the Sep 2010 issue of the European Journal of Cancer.

Another meta-analysis led by Chen P and colleagues from Shanghai Institutes for Biological Sciences - Chinese Academy of Sciences in Shanghai resulted in a similar conclusion.

Chen et al. analysed data from 11 studies on vitamin D intake, 7 studies on circulating 25(OH)D levels, 3 studies of circulating 1alpha,25(OH)(2)D levels and found a significant inverse association between vitamin D intake and breast cancer risk.

The overall reduction in the risk of breast cancer was 9 percent in people with a high intake of vitamin D compared to those with low intake.

Among those who had the highest intake of the vitamin, the risk of breast cancer was reduced by 45 percent compared to those with lowest intake.

The findings were published in the June 2010 issue of Breast cancer Research and Treatment.

Individual epidemiological studies have previously found the maximum reduction in breast cancer risk associated with highest levels of vitamin D was up to 70 percent.

The chemo-preventative properties against breast cancer and other malignancies are more than observational.  Laboratory studies also suggested that vitamin D can prevent development of breast cancer.

Krishnan A.V. and colleagues from Stanford University school of Medicine has recently published a review article in the July 2010 issue of Journal of Steroid Biochemistry and Molecular Biology saying that calcitriol or 1,25-dihydroxyvitamin D3, - the hormonally active metabolite of vitamin D - is involved in preventing development of breast cancer in a number of pathways.

They found calcitriol inhibits the growth of breast cancer cells by inducing cell cycle arrest and by stimulating apoptosis. Calcitriol has also been found to decrease the expression of aromatase, the enzyme that catalyzes estrogen synthesis selectively in breast cancer cells and the tissue surrounding breast tumors.

Estrogen is known to promote the growth of breast cancer and some chemo-preventative drugs are designed to exactly prevent this hormone from interacting with its receptors.

The researchers proposed that "the inhibition of estrogen synthesis and signaling by calcitriol and its anti-inflammatory actions will play an important role in the use of calcitriol for the prevention and/or treatment of breast cancer."

It should be noted that low vitamin D levels may not have any preventative effect against breast cancer.

In 1997, the Food and Nutrition Board of the Institute of Medicine said people ages 0 to 50 years old need 200 IU of vitamin D, those ages 51 to 70 400 IU, and those ages 71 or older 600 IU, according to Linus Pauling Institute. 

Numerous studies have suggested that these levels of vitamin D could be pathogenic. Dr. Cannell, a vitamin D expert and director of the vitamin D Council suggests adults need around 5000 IU per day to maintain healthy body functions, and that even higher doses may be needed to fight diseases.

The Canadian Cancer Society has already recommended 1000 IU as the minimum to maintain one’s body functions. 

The daily dose of vitamin D is important. But Dr. Cannell says per his website that cofactors including magnesium, zinc, vitamin k2, boron and a small amount of vitamin A are also needed for vitamin D to be better utilized.

Vitamin D has not been widely recognized as preventative agent by breast cancer organizations like  Susan G. Komen for the Cure, which is supported by numerous corporations.

Breast cancer is expected to be diagnosed in about 200,000 men and women in the United States in 2010 and the disease will kill about 50,000 people in the country this year, according to health organizations.

Foodconsumer.org has reported early on many things men and women can do to prevent breast cancer. More reports will be published on the site in the National Breast Cancer Awareness to help readers better understand the disease and how to prevent it.

David Liu and editing by Rachel Stockton

(This is the edited version)