High prevalence of vitamin D deficiency despite supplementation in premenopausal women with breast cancer undergoing adjuvant chemotherapy.
Crew KD, Shane E, Cremers S, McMahon DJ, Irani D, Hershman DL.
J Clin Oncol. 2009 May 1;27(13):2151-6. Epub 2009 Apr 6.
PMID: 19349547
DOI: 10.1200/JCO.2008.19.6162
Conclusion Vitamin D deficiency is highly prevalent in women with breast cancer. The current recommended dietary allowance of vitamin D is too low to increase serum 25-OHD greater than 30 ng/mL. Optimal dosing for bone health and, possibly, improved survival has yet to be determined.
Benefits of Vitamin D Supplementation
Joel M. Kauffman, Ph.D.
Journal of American Physicians and Surgeons
Volume 14 Number 2 - Summer 2009
Clinical trials show that vitamin D supplementation at higher
levels than previously recommended is beneficial for many
conditions. It decreases the frequency of falls and fractures, helps
prevent cardiovascular disease, and reduces symptoms of colds or
influenza. Benefits are also seen in diabetes mellitus, multiple
sclerosis, Crohn disease, pain, depression, and possibly autism.
Sunlight does not cause an overdose of vitamin D production,
and toxicity from supplementation is rare. Dose recommendations
are increasing, but appear to be lagging the favorable trial results. A
number of common drugs deplete vitamin D levels, and others may
limit its biosynthesis from sunlight.
People with adequate levels from sun exposure will not benefit
from supplementation. While dietary intake is helpful,
supplementation is better able to raise serum 25-hydroxyvitamin D ,
the major circulating metabolite, to the level now thought adequate,
30-50 ng/mL.
Where there is inadequate daily sun exposure, oral doses of
1,000-2,000 IU/d are now considered routine, with much higher
doses (up to 50,000 IU) for rapid repletion now considered safe.
Not enough vitamin D: health consequences for Canadians.
Schwalfenberg G.
Can Fam Physician. 2007 May;53(5):841-54. Review
PMID: 17872747
Conclusion
Low levels of VTD are considered a major public health problem in Canada, especially during the winter. Those with risk factors should be screened for low 25(OH)D levels and repletion therapy instituted if needed. Researchers have estimated that the oral dose of vitamin D3 to attain and maintain 25(OH)D levels >80 nmol/L is 2200 IU/d if baseline levels are 20 to 40 nmol/L, 1800 IU/d if levels are 40 to 60 nmol/L, and 1160 IU/d if levels are between 60 and 80 nmol/L.64
We need to ensure that patients have healthy blood levels of 25(OH)D to prevent levels of parathyroid hormone from rising and to maximize absorption of calcium, magnesium, and phosphate. Positive effects on bone are marginal at best unless patients consume at least 800 IU/d of VTD. The emerging and exciting role of the VTD receptor and the actions of VTD in maintaining health in other cell types have become more apparent during the last decade.
The role of vitamin D in cancer prevention.
Garland CF, Garland FC, Gorham ED, Lipkin M, Newmark H, Mohr SB, Holick MF.
Am J Public Health. 2006 Feb;96(2):252-61. Epub 2005 Dec 27. Review.
PMID: 16380576
DOI: 10.2105/AJPH.2004.045260
Vitamin D status differs by latitude and race, with residents of the northeastern United States and individuals with more skin pigmentation being at increased risk of deficiency. A PubMed database search yielded 63 observational studies of vitamin D status in relation to cancer risk, including 30 of colon, 13 of breast, 26 of prostate, and 7 of ovarian cancer, and several that assessed the association of vitamin D receptor genotype with cancer risk.
The majority of studies found a protective relationship between sufficient vitamin D status and lower risk of cancer. The evidence suggests that efforts to improve vitamin D status, for example by vitamin D supplementation, could reduce cancer incidence and mortality at low cost, with few or no adverse effects