Higher vitamin D levels correlated with improved breast cancer prognosis

An article published online on October 9, 2013 in Breast Cancer Research and Treatment reports the results of a meta-analysis conducted by Canadian researchers which found an association between higher serum levels of vitamin D and better prognosis for women with early stage breast cancer.

For their analysis, Pamela J. Goodwin of the University of Toronto and her colleagues selected eight studies involving a total of 5,691 women diagnosed with breast cancer from 1973 to 2010. Blood samples were collected, on average, within 90 days of diagnosis or shortly before treatment. Deficient levels of vitamin D were uncovered in 38.6% of the subjects. 

When the lowest versus highest categories of serum vitamin D were compared in a pooled analysis, women whose levels were low had a risk of recurrence that was more than double that of subjects whose levels were high and a risk of death that was 76% higher.  The authors remark that vitamin D, when activated, can alter the transcription and expression of specific genes, resulting in growth arrest, apoptosis, aromatase suppression, decreased inflammation, and inhibition of angiogenesis, invasion and metastasis, all of which help combat cancer. 

“These findings support an association of low levels of vitamin D with increased risk of recurrence and death in early stage breast cancer patients,” the authors conclude.  “Given the observational nature of the included studies, it cannot be concluded that this association is causal. Further research is warranted to investigate the potential beneficial effects of vitamin D in breast cancer.”

 http://www.lef.org/whatshot/2013_10.htm?utm_source=DailyHealthBulletin&utm_medium=email&utm_term=WhatsHot&utm_content=Body+Title&utm_campaign=DHB_131012&l=0#Higher-vitamin-D-levels-correlated-with-improved-breast-cancer-prognosis

Where did the Vitamin D Council get its recommendation that adults take 5,000 IU/day of vitamin D3 for the rest of their life? The Institute of Medicine’s Food and Nutrition Board say 600 IU/day is enough for adults and the Endocrine Society says 2,000 IU/day is enough for most adults.

We think the safest thing to do while all the research is going on is to maintain natural vitamin D levels. By natural, we mean those levels obtained by those with natural sun exposure, such as lifeguards, some roofers and gardeners, and others who work in the sun and expose a lot of skin to sunshine. This is how our ancestors behaved throughout our evolutionary history.

The best study that examined the vitamin D levels of people who get plenty of sun exposure was published last year. Researchers discovered that free-living hunter gatherers living around the African equator (where humans evolved) have average vitamin D levels of 46 ng/ml (115 nmol/L).

Luxwolda MF, Kuipers RS, Kema IP, Dijck-Brouwer DA, Muskiet FA. Traditionally living populations in East Africa have a mean serum 25-hydroxyvitamin D concentration of 115 nmol/l. Br J Nutr. 2012 Nov 14;108(9):1557-61.

Most people will not have their blood tested unless their doctor recommends it. So we needed a recommended dose that:

• Is easy to obtain at most pharmacies.
• Will get at least 97% of people above 30 ng/ml.
• Will get most people above 40 ng/ml, and close to around 50 ng/ml.
• Will not cause anyone to get toxic levels.

When we decided on a recommendation with the four goals above in mind, we also had to take into account body weight. Besides genetics, body weight is the single biggest determinate of vitamin D levels. The more you weigh, the more vitamin D you need to take.

Professor Robert Heaney of Creighton University details in the study below just how high vitamin D supplementation/input needs to be to reach the vitamin D level goals above.

Drincic AT, Armas LA, Van Diest EE, Heaney RP. Volumetric dilution, rather than sequestration best explains the low vitamin D status of obesity. Obesity (Silver Spring). 2012 Jul;20(7):1444-8. doi: 10.1038/oby.2011.404.

Together with his coauthors, Professor Heaney stated that for a normal weight adult, 5,000 IU/day of total input was needed to obtain a vitamin D level of 40 ng/ml. Of course the final vitamin D level obtained by any dose depends on baseline level, sun exposure and genetics. But he was speaking of the average adult.

For those who want a more careful calculation, he stated his data showed that 70-80 IU/day/kg of body weight total input is needed to obtain a 25(OH)D of 40 ng/ml. That works out to about 35 IU/day/pound. So a 100 pound woman would need 3,500 IU/day of total input but a 300 pound lineman would need 10,500 IU/day. Keep in mind this is total input, which includes sunlight, diet and supplements.

Taking all these factors into account, we conclude a recommendation of 5,000 IU/day is about right for the average adult.

http://www.vitamindcouncil.org/blog/why-does-the-vitamin-d-council-recommend-5000-iuday/