No bone benefit for high-dose vitamin D3
University of Helsinki researchers found that 400 IUs of vitamin D3 daily was enough to make sure children under two years had sufficient vitamin D.
They had hypothesized that higher dosages of vitamin D supplementation would lead to increased bone strength and to decreased frequency of infections in early childhood.in a northern European population with limited sunlight exposure.
Trial methodology
The randomized clinical trial involved a sample of 975 healthy term infants at a maternity hospital in Helsinki, Finland. A total of 489 were randomly assigned to the 400-IU group and 486 to the 1200-IU group.
Study recruitment was between January 14, 2013 and June 9, 2014 and last follow-up was May 30, 2016.
Ethnicity was restricted to Northern European to exclude the effect of skin pigmentation on vitamin D status.
Both study preparations, manufactured by Orion Pharmaceuticals, contained vitamin D3 dissolved in medium-chain triglyceride oil and were identical in appearance.
Vitamin D supplements were administered orally once daily in five drops for both concentrations.
Bone strength and resisting infections
At birth, 914 of 955 of the infants were vitamin D sufficient (had a 25[OH]D concentration ≥20.03 ng/mL), reflecting adequate maternal vitamin D intake.
At age 24 months, 809 of 814 of participants were vitamin D sufficient. None had a 25(OH)D concentration greater than 100.16 ng/mL or severe hypercalcemia, which are indicators of vitamin D toxicity.
“These findings imply that a daily dose of 1200 IU of vitamin D3 in this age group is safe, but even 400 IU will maintain vitamin D sufficiency in most children,” said researchers.
“…our results support the findings that, in vitamin D–sufficient children, additional vitamin D supplementation provides no further benefit in resisting infections.”
Since 2010, Finnish public health authorities have improved vitamin D intake at population level by food fortification and promotion of supplementation.
Failure to incorporate measurement of vitamin D nutrient level
Karen Howard, CEO and executive director of the Organic & Natural Health Association (O&N), who was not involved in the work, said it fails to incorporate measurement of the vitamin D nutrient level.
“It’s conclusion that 400 IU may, vs. is adequate is indicative of the study design limitation. That said, standard practice is to give our newborns 400 IUs of D3 daily. I suspect there are adults who can maintain a sufficient vitamin D level by taking the recommended 400 IUs daily,” she told us.
“However, I also suspect it would be highly unique for the vast majority of grownups to achieve a sufficient vitamin D blood level by taking the standard newborn dose. Testing obviously has demonstrated that to be true in the GrassrootsHealth nutrient field studies.”
O&N is a US trade group petitioning FDA to approve a health claim connecting vitamin D supplementation with a reduction in premature birth risk.
The clinical trial by University of Helsinki researchers was one of two studies published recently in JAMA Pediatrics that link vitamin D supplementation to infant and maternal health.
The other was a meta-analysis that found vitamin D supplementation may reduce the risk of infants being small for gestational age and improve growth during infancy.
Source: JAMA Pediatrics
Published online, doi:10.1001/jamapediatrics.2018.0602
"Effect of Higher vs Standard Dosage of Vitamin D3 Supplementation on Bone Strength and Infection in Healthy Infants: A Randomized Clinical Trial”
Authors: Jenni Rosendahl, et al.
