NUTRITION – VITAMIN D – MUSCLE MASS & STRENGTH


2 ARTICLES + 1 GRAPHIC – ADAM VIRGILE



A SYSTEMS INVESTIGATION INTO VITAMIN D AND SKELETAL MUSCLE REPAIR REGENERATION AND HYPERTROPHY – 2015


Daniel J. Owens1, James P. Morton1, Graeme L. Close1 et al
INTRODUCTION
– Skeletal muscle is a direct target for Vitamin D
– Observational studies suggest 25[OH]D correlates with recovery of skeletal muscle following eccentric contractions in humans and crush injury in rats
METHOD
(1) 20 males with low serum 25[OH]D (45 ± 25 nmol.L-1)
(2) Prior to and following 6-weeks of supplemental Vitamin D3 (4,000 IU.day-1) or placebo (50 mg cellulose) participants performed 20×10 damaging eccentric contractions of the knee extensors with peak torque measured over the following 7 days of recovery
RESULTS
(1) Supplemental Vitamin D3 increased serum 25[OH]D and improved recovery of peak torque at 48 hours and 7 days post-exercise
(2) Increased myotube hypertrophy at 7 and 10 days post-damage.
CONCLUSION
– Together, these preliminary data are the first to characterise a role for Vitamin D in human skeletal muscle regeneration
– It suggests that maintaining serum 25[OH]D may be beneficial for enhancing reparative processes and potentially for facilitating subsequent hypertrophy


VITAMIN D AND MUSCLE FUNCTION IN THE ELDERLY – 2014


Girgis CM.
PURPOSE OF REVIEW
– Circumstantial evidence suggests that vitamin D deficiency may contribute to age-related changes in skeletal muscle
This review discusses recent clinical trials examining effects of vitamin D on muscle function in the elderly
– We pose the important question: can vitamin D reverse muscle ageing?

RECENT FINDINGS
– Observational studies report an association between vitamin D and muscle atrophy/weakness in elderly subjects
– Interventional studies suggest frail, elderly subjects may benefit from vitamin D by displaying reduced falls, improved muscle function and increased muscle fibre size
– However, meta-analyses do not report convincing effects of vitamin D in the elderly
– This may be because of factors including lack of standardized endpoints for muscle function, variable study design and different doses of D supplementation
– The evidence base is therefore inconsistent
– Until these issues are clarified, the safest option is to aim for conservative vitamin D targets that are sufficient for normal calcium homeostasis


 

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