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Providing perspectives on recent research into vitamins and nutritionals

Vitamin D intake vs serum 25OHD level after 12mo supplementation

Getting a Grip on Vitamin D and Muscle Strength

By Michael McBurney

Vitamin D status has been linked to muscle function. Low serum 25(OH)D levels are associated with muscle weakness in elderly people (Smit et al, 2012). Vitamin D supplementation in healthy men and women 70y and older with mean serum 25(OH)D levels of ~55 nmol/L increased these levels to ~85 nmol/L and significantly improved quadriceps strength (Pfeifer et al, 2009). These findings are in adults.

Harvey and colleagues wondered if maternal vitamin D status during pregnancy might affect muscle development in toddlers. Using a prospective UK-based mother-offspring cohort (Southampton Women’s Survey, SWS), they investigated relationships between maternal blood 25(OH)D status at 34wk gestation and child muscle strength at 4y of age in 678 mother-child pairs. Maternal serum 25(OH)D levels were positively associated with toddler hand grip strength after adjusting for height. This finding is not totally unexpected. Ceglia and colleagues reported that vitamin D supplementation (4,000 IU/d for 4 months) in women ≥65y, with average baseline serum 25(OH)D levels ~47 nmol/L, significantly increased intramyonuclear VDR concentration 30% and muscle fiber size by 10%.

A great deal of insight into the relationship between vitamin D intake and serum 25(OH)D status has been reported in the last couple of years. Today’s graphic, Slide 3 downloaded from the appendix of the free article by Gallagher et al, 2012, shows the relationship between the amount of vitamin D3 (IU/d) consumed for 12 months and their serum 25(OH)D levels in Caucasian women, stratified by body mass index (BMI).  [Note correction to figure. 3. Dotted line corresponds to BMI of 25-29.9 and dashed line corresponds to BMI ≥ 30.0 kg/m2]. A similar relationship has been reported for African American women (Gallagher et al, 2013). There is little reason to expect that the slope of the line would be dramatically different for men.

Neither research group (Harvey et al, 2014, Ceglia et al, 2013, Gallagher et al, 2012, Gallagher et al, 2013)considered genetics which can influence vitamin D action. People having a specific vitamin D receptor (VDR) genotype, the Fok-qI polymorphism, seem to need a higher vitamin D intake to achieve similar serum 25(OH)D levels (when compared with persons have other VDR genotypes) (Neyestani et al, 2012). This may explain the variability in response among women receiving the same vitamin D3 dose for 12 months (see Figure 3/image associated with this post. The impact of genetic polymorphism on vitamin D requirements needs further investigation.

In the grip of the Polar Vortex which limits skin exposure to sunshine, you do not have to feel totally powerless with respect to vitamin D needs to maintain serum 25(OH)D levels.

Main Citation

Harvey NC, Moon RJ, Sayer AA, Ntani G, Davies JH< Javaid MK, Robinson SM, Godfrey KM, Inskip HM, Cooper C, and the Southampton Women’s Survey Study Group. Maternal antenatal vitamin D status and offspring muscle development: findings from the Southampton Women’s Study. 2014 JCEM


Smit E, Crespo CJ, Michael Y, Ramirez-Marrero FA, Brodowicz GR, Bartlett S, Andersen RE. The effect of vitamin D and frailty on mortality among non-institutionalized US older adults. 2012 EJCN

Pfeiffer M, Begerow B, Minne HW, Suppan K, Fahrleitner-Pammer A, Dobnig H. Effects of long-term vitamin D and calcium supplementation on falls and parameters of muscle function in community-dwelling older individuals.

Ceglia L, Niramitmahapanya S, d Silva Morais M, Rivas DA, Harris SS, Bischoff-Ferrari H, Fielding RA, Dawson-Hughes B. A randomized study on the effect of vitamin D3 supplementation on skeletal muscle morphology and vitamin D receptor concentration in older women. 2013 JCEM

Neyestani TR, Djazayery A, Shab-Bidar S, Eshraghian MR, Kalayi A, Shariatzadeh N, Khalaji N, Zahedirad M, Gharavi A, Houshiarrad A, Chamari M, Asadzadeh S. Vitamin D receptor Fok-I polymorphism modulates diabetic host response to vitamin D intake: Need for nutrigenetic approach. 2012 Diab Care

Gallagher JC, Sai A, Templin II T, Smith L. Dose response to vitamin D supplementation in postmenopausal women: A randomized trial. 2012 Ann Intern Med http:/

Gallagher  JC, Peacock M, Yalamanchili V, Smith LM. Effects of vitamin D supplementation in older African American women. 2013 JCEM