1700 IU vitamin D (50000 monthly) helped antarctic explorers – RCT Jan 2012

Skeletal and hormonal responses to vitamin D supplementation during sunlight deprivation in Antarctic expeditioners.

Osteoporos Int. 2012 Jan 4.
Iuliano-Burns S, Ayton J, Hillam S, Jones G, King K, Macleod S, Seeman E.
Austin Health, University of Melbourne, Parkville, Australia, sandraib@unimelb.edu.au.

Sunlight deprivation results in vitamin D deficiency but serum vitamin D levels can be maintained above 50nmol/L when supplemented with 50,000IU at least every alternate month.

INTRODUCTION: Antarctic expeditioners are exposed to prolonged sunlight deprivation resulting in vitamin D deficiency.
We hypothesised that monthly dosing of 50,000 IU vitamin D (~1,600 IU daily) will increase serum 25-hydroxyvitamin D (25(OH)D), suppress parathyroid hormone (PTH) and improve bone mineral density (BMD), 50,000 IU alternate months (~800 IU daily) will maintain these measures, while a single 50,000 IU dose pre-departure (~1,00 IU daily) {137 IU daily} will not be protective.

METHODS: This was a randomised double-blind study involving 110 healthy adults: 91 males, mean age 41 years (range 24-65 years) working in Antarctica for up to 12 months, who we administered 50,000 IU vitamin D3 monthly, alternate months or a single dose pre-departure. Serum 25(OH)D, PTH, osteocalcin, CTx and calcium were assessed at baseline, mid- and end of expedition. Proximal femur and lumbar spine BMD were assessed pre- and post-expedition.

RESULTS: Baseline 25(OH)D was 59?±?14 nmol/L. By mid-expedition, 25(OH)D increased by 7 nmol/L in those supplemented monthly (p?<?0.05) and remained unchanged in those supplemented in alternate months.

In those given a single dose pre-departure, 25(OH)D decreased by 8 nmol/L (p?<?0.05) and PTH increased by 27% (p?<?0.09).
Serum osteocalcin increased by ~22% in all groups but BMD remained unchanged.
If serum 25(OH)D was >50 nmol/L at baseline, 25(OH)D was maintained above this level with all regimens.
If 25(OH)D was <50 nmol/L at baseline, monthly or alternate month regimens were needed to achieve levels >50 nmol/L, the single pre-departure dose was ineffective.

CONCLUSION: During sunlight deprivation of up to 12 months, serum 25(OH)D levels can be maintained above 50 nmol/L when expeditioners are provided with 50,000 I U at least every alternate month.

PMID: 22215183

PDF, which was available to the public Dec 2012, is attached at the bottom of this page

Fig. 1

Time course of changes to 25(OH)D in expeditioners with serum 25(OH)D levels above (left panels) or below
(right panels) 50 nmol/L at baseline, and then treated with 50,000 IU monthly

23.6 ng baseline ==> 26.4 ng for monthly 50,000 IU of vitamin D (1,600 daily)
No change if just get bimonthly 50,000 IU of vitamin D (800 daily)
VitaminDWiki suspects that very few of the participants were overweight or pregnant

This should apply not only to those living very far from the equator, but also to those who get very little sun

See also VitaminDWiki

IU of vitamin D to add vs X

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