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Response to Vitamin D: summary chart of 8 studies – March 2013

All-Source Basal Vitamin D Inputs Are Greater Than Previously Thought and Cutaneous Inputs Are Smaller.

J Nutr. 2013 Mar 20.
Heaney RP, Armas LA, French C.
Creighton University, Omaha, NE.

The magnitude of vitamin D inputs in individuals not taking supplements is unknown; however, there is a great deal of information on quantitative response to varying supplement doses.

We reanalyzed individual 25-hydroxyvitamin D [25(OH)D] concentration data from 8 studies involving cholecalciferol supplementation (total sample size = 3000). We extrapolated individual study dose-response curves to zero concentration values for serum 25(OH)D by using both linear and curvilinear approaches and measured seasonal oscillation in the serum 25(OH)D concentration. The total basal input (food plus solar) was calculated to range from a low of 778 iu/d in patients with end-stage renal disease to a high of 2667 iu/d in healthy Caucasian adults. Consistent with expectations, obese individuals had lower baseline, unsupplemented 25(OH)D concentrations and a smaller response to supplements. Similarly, African Americans had both lower baseline concentrations and lower calculated basal, all-source inputs.

Seasonal oscillation in 4 studies ranged from 5.20 to 11.4 nmol/L, reflecting a mean cutaneous synthesis of cholecalciferol ranging from 209 to 651 iu/d at the summer peak.

We conclude that:

  • 1) all-source, basal vitamin D inputs are approximately an order of magnitude higher than can be explained by traditional food sources;
  • 2) cutaneous, solar input in these cohorts accounts for only 10-25% of unsupplemented input at the summer peak; and
  • 3) the remainder must come from undocumented food sources, possibly in part as preformed 25(OH)D.

PMID: 23514768


Lots more in the publication, but publisher does not permit access by people who do not pay.
The Dr. Heaney has provided an excellent chart which was used in the publication.

Average Response to vitamin D (many higher, many lower)

dashed lines and text added by Vitamin D Life
Response - 8 studies  bit.ly/16TuWp5


See also Vitamin D Life

see wikipage: http://www.vitad.org/tiki-index.php?page_id=1293

How much to supplement Grassroots Jan 2013

Short url = http://bit.ly/16TuWp5

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