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.
Maternal vitamin D status during pregnancy and childhood bone mass at age 9 years: a longitudinal study.
Javaid MK, Crozier SR, Harvey NC, Gale CR, Dennison EM, Boucher BJ, Arden NK, Godfrey KM, Cooper C; Princess Anne Hospital Study Group.
Lancet. 2006 Jan 7;367(9504):36-43. Erratum in: Lancet. 2006 May 6;367(9521):1486.
PMID: 16399151
doi:10.1016/S0140-6736(06)67922-1
Interpretation
Maternal vitamin D insufficiency is common during pregnancy and is associated with reduced bone-mineral accrual in the offspring during childhood; this association is mediated partly through the concentration of umbilical venous calcium. Vitamin D supplementation of pregnant women, especially during winter months, could lead to longlasting reductions in the risk of osteoporotic fracture in their offspring.
Reducing the Burden of Disease Through Adequate Intake of Vitamin D3.
A presentation at University of California, San Diego,
April 9, 2008
by William B. Grant, Ph.D
Vitamin D deficiency is associated with worse cognitive performance and lower bone density in older African Americans.
Wilkins CH, Birge SJ, Sheline YI, Morris JC.
J Natl Med Assoc. 2009 Apr;101(4):349-54.
PMID: 19397226
CONCLUSIONS: Vitamin D deficiency in older African Americans was associated with worse cognitive performance and lower BMD of the hip
Plasma calcidiol, season, and serum parathyroid hormone concentrations in healthy elderly men and women.
Dawson-Hughes B, Harris SS, Dallal GE.
Am J Clin Nutr. 1997 Jan;65(1):67-71.
PMID: 8988915
Plasma calcidiol and serum PTH concentrations were inversely related, with PTH rising slowly as calcidiol concentrations declined below 110 nmol/L (95 CI: 60, 168 nmol/L). More than 90% of the men and women had calcidiol concentrations below this value in the wintertime. The high prevalence of lower wintertime calcidiol values may increase risk of bone loss in elderly men and women.
"Researchers at Johns Hopkins are reporting what is believed to be the first conclusive evidence in men that the long-term ill effects of vitamin D deficiency are amplified by lower levels of the key sex hormone estrogen, but not testosterone.
In a national study in 1010 men, to be presented Nov. 15 at the American Heart Association's (AHA) annual Scientific Sessions in Orlando, researchers say the new findings build on previous studies showing that deficiencies in vitamin D and low levels of estrogen, found naturally in differing amounts in men and women, were independent risk factors for hardened and narrowed arteries and weakened bones. Vitamin D is an essential part to keeping the body healthy, and can be obtained from fortified foods, such as milk and cereals, and by exposure to sunlight.
Effectiveness and safety of vitamin D in relation to bone health.
Cranney A, Horsley T, O'Donnell S, Weiler H, Puil L, Ooi D, Atkinson S, Ward L, Moher D, Hanley D, Fang M, Yazdi F, Garritty C, Sampson M, Barrowman N, Tsertsvadze A, Mamaladze V.
Evid Rep Technol Assess (Full Rep). 2007 Aug;(158):1-235. Review.
PMID: 18088161
Is a lower dose of vitamin D supplementation enough to increase 25(OH)D status in a sunny country?
Pignotti GA, Genaro PS, Pinheiro MM, Szejnfeld VL, Martini LA.
Eur J Nutr. 2009 Nov 28. [Epub ahead of print]
PMID: 19946776
CONCLUSION: The dose given (400 IU/day) was not enough to achieve 25(OH)D concentration, considered optimal for bone health.