Saturday Dec. 20, 2008 (foodconsumer.org) -- Overwhelming evidence has suggested that a wide variety of cancers including breast cancer have something to do with vitamin D insufficiency or deficiency.   Only a very few studies failed to establish the association.

One study led by Freedman DM and colleagues from the National Cancer Institute and published in the April 2008 issue of Cancer Epidemiology Biomarkers Prevention is one of those that did not find any association between serum vitamin D and breast cancer risk.

Freedman's study involved 1,005 incident breast cancer cases and 1,005 age-matched controls who entered the study between 1993 and 2001 and were followed through 2005. The subjects were aged 55 to 74 years and serum 1, 25-hydrooxyvitamin D and 1, 25-dihydroxyvitamin D were tested at baseline.

The researchers did not find any association between 1, 25-hydroxyvitamin D or 1, 25-dihydroxyvitamin D and breast cancer risk. That is, those who were in the quintile of highest levels of 1, 25-hydroxyvitamin D were at the same risk as those who were in the quintile of lowest levels.

Even worse, those who had the highest levels of 1, 25-dihydroxyvitamin D, most potent active form of vitamin D, were 23 percent more likely to be diagnosed with breast cancer than those with the lowest levels.

The study has some limitation, a health observer at foodconsumer.org suggested.   Although test results of vitamin D indicated the accurate vitamin D status for an individual, the vitamin D level at the time of testing may not be indicative of the individual's history of exposure to vitamin D or sunlight.

More than a dozen of studies including those by Garland CF and Garland FC of the University of California in San Diego that considered the history of exposure to sunlight or intake of vitamin D have found that high vitamin D levels are associated with a lower risk of breast cancer.

A recent study by Garland et al. found “ individuals with serum 25(OH) D of approximately 52 ng/ml had 50% lower risk of breast cancer than those with serum <13 ng/ml.”   To achieve such a serum level of vitamin D, one needs to take 4000 IU of vitamin D3 daily.

Garland's study published in J Steroid Biochem Mol Biol. 2007 Mar;103(3-5):708-11 has been recently confirmed by Abbas S and colleagues from German Cancer Research Center in Heidelberg, Germany.

Abbas et al. published their study in the Jan 2009 issue of International Journal of Cancer showed that compared to premenopausal women who had only less than 30 nmol/L vitamin D, women who had 30-45, 45-60, >/=60 nmol/L were at a 32, 41 and 55 percent reduced risk of breast cancer respectively.