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Muscle strength not increased by Vitamin D - 96 percent were not deficient – RCT April 2017

The effect of high-dose vitamin D supplementation on muscular function and quality of life in postmenopausal women - a randomized controlled trial.

Clin Endocrinol (Oxf). 2017 Apr 19. doi: 10.1111/cen.13353. [Epub ahead of print]
Grimnes G1, Emaus N2, Cashman KD3, Jorde R1.

VitaminDWiki Summary
  • Average daily 6,700 IU Vitamin D vs 800 IU + 1 gram of Calcium for a year
  • This study was based on a trial which finished in 2009, before the realization that increasing Vitamin D levels only helps those who are deficient

Hidden in the rented study

  • 96% of the women had vitamin D levels> 30 nmol
  • 30% had > 75 nmol

Amazingly they failed to measure

  • Rate of falls
  • Speed of muscle response (which prevents falls)
    They only measured knee strength in about half of the participants

See also VitaminDWiki

Chart from ency editor Feldman 2005. Shows that those with slow muscle twitch are able to speed up response by taking vitamin D supplements.  PROOF

Observational studies have suggested positive associations between serum 25-hydroxyvitamin D (25(OH)D) levels and muscular strength, balance and quality of life. Our aim was to examine whether high-dose vitamin D supplementation would improve these measures as compared to standard-dose vitamin D, as well as the possible muscular effects of Single Nucleotide Polymorphisms (SNPs) in genes encoding vitamin D-related enzymes.

A 12-month randomized, double-blind, controlled trial where the participants received daily elemental calcium (1,000 mg) plus vitamin D3 (800 IU). In addition, the participants were randomized to receive either capsules with vitamin D3 (20,000 IU) or matching placebos to be taken twice a week.

297 postmenopausal women with osteopenia or osteoporosis.

Muscle strength (handgrip and knee extensor strength), balance (tandem test) and quality of life (EQ-5D) were measured at baseline and after 12 months. The subjects were genotyped for SNPs related to vitamin D metabolism.

Of the 297 included women, 275 completed the study. Mean serum 25(OH)D levels dramatically increased in the high-dose group (from 64.7 to 164.1 nmol/l; p<0.01), while a more moderate increased was observed in the standard-dose group (from 64.1 to 81.8 nmol/l; p<0.01). There was no significant difference between the groups in change in muscular strength, balance or quality of life over the intervention period. Polymorphisms in rs3829251 (located in the 7-dehydrocholesterol reductase gene) was associated with muscle strength and treatment effects.

One-year treatment with high-dose vitamin D had no effect on muscular strength, balance or quality of life in postmenopausal women with osteopenia or osteoporosis as compared to standard-dose. The association between rs3829251 and muscle strength needs confirmation in other populations

PMID: 28423480 DOI: 10.1111/cen.13353