Maintaining Strong Muscles and Bones with Vitamin D all Year
For those living in the northern hemisphere, the days are getting shorter and colder. Both factors contribute to less skin exposure to sunlight, leading to lower serum 25(OH)D concentrations unless we increase our intake of vitamin D rich foods or use dietary supplements.
Vitamin D deficiency is widespread in newborn. Streym and colleagues analyzed cord blood from 107 Caucasian women and their infants at birth, 4 and 9 months living in Denmark. Serum 25(OH)D levels < 25 mmol/L and between 25-50 nmol/L were defined as deficient and insufficient, respectively. Plasma 25(OH)D levels were higher in women using supplements (79 vs 53 nmol/L) and 23% of women were insufficient. As the study progressed, fewer women were using dietary supplements and plasma 25(OH)D levels decreased. There was a positive correlation between maternal plasma 25(OH)D and cord blood concentrations. At birth, 15% of infants were deficient and 46% were insufficient. Plasma 25(OH)D levels were lower during winter. Maternal plasma 25(OH)D level was the only significant determinant of infant vitamin D status at birth and visit 2 whereas season was also important at 9 mo. Based on widespread vitamin D deficiency in newborn Danish children, the authors recommend vitamin D supplementation daily for infants (400 IU).
A similar story can be told for adults. Caillet and colleagues examined reimbursement data from 1,311 middle-aged French adults who had been prescribed vitamin D supplementation based on serum 25(OH)D levels. Physicians prescribed a very high dose (100,000 or 200,000 IU) in 32.6% of patients. Only 51% of patients received further vitamin D supplementation after a single loading dose. The most common daily vitamin D dose over the 7 month followup was <1000 IU (~47%) followed by 1000-2000 IU (~30%) with a median of 1,600 IU/day.
Maintaining optimal vitamin D status (> 50 nmol/L) throughout the year (and life) is important. Low vitamin D status is associated with reduced muscle mass and impaired physical performance (Tieland et al, 2013). In both active and inactive ambulatory adults, maintaining 25(OH)D levels above 50 nmol/L is important for muscular strength and mobility (Bischoff-Ferrari et al, 2004).
A recent economic analysis “Osteoporosi and the Benefits of Using Calcium, Vitamin D, and Magnesium” reports that the average expenditure per osteoporosis-attributed fracture in the US per year is $11,020. 8.2 million American women over 55y are at risk of osteoporosis. Over 7 years (2013-2020), if everyone were to supplement to maintain adequate vitamin D levels and calcium intakes, over $12 billion in cumulative net osteoporosis savings could be realized. These are BIG numbers.
Be prudent. If you live in the southern hemisphere, go outside and enjoy some sunshine. If you live in the northern hemisphere (or prefer not to spend time in the sun), a vitamin D supplement is smart.
Streym S, Moller UK, Rejnmark L, Heickendorff L, Mosekilde L, Vestergaard P. Maternal and infant vitamin D status during the first 9 months of infant life – a cohort study. 2012 Eur J Clin Nutr doi:10.1058/ejcn.2013.152
Brock K, Huang W-Y, Fraser DR, Ke L, Tseng M, Stolzenberg-Solomon R, Peters U, Ahn J, Purdue M, Mason RS, McCarty C, Ziegler R, Graubard B. Low vitamin D status is associated with physical inactivity, obesity and low vitamin D intake in a large US sample of healthy middle-aged men and women. 2010 J Steroid Biochem Mol Biol doi:10.1016/j.jsbmb.2010.03.091
Caillet P, Souberbielle JC, Jaglal SB, Reymondier A, Van Ganse E, Chapurlat R, Schott AM. Vitamin D supplementation in a healthy, middle-aged population: actual practices based on data from a French comprehensive regional health-care database. 2013 Eur J Clin Nutr doi:10.1058/ejcn.2013.182
Tieland M, Brouwer-Brolsma EM, Nienaber-Rousseau C, van Loon LJC, De Groot LCPGM. Low vitamin D status is associated with reduced muscle mass and impaired physical performance in frail elderly people. 2013 Eur J Clin Nutr doi:10.1038/ejcn.2013.144
Bischoff-Ferrari HA, Dietrich T, Orav EJ, Hu FB, Zhang Y, Karlson EW, Dawson-Hughes B. Higher 25-hydroxyvitamin D concentrations are associated with better lower-extremity function in both active and inactive persons aged ≥60 y. 2004 Am J Clin Nutr 80:752