While many organisations have published guidelines for adequate vitamin D intake and status, many do not provide guidance on how to tackle vitamin D deficiency or advise on optimum levels, say researchers from the NutriProfiel project, writing in the Journal of Nutritional Science.
The NutriProfiel project, a collaboration between the Gelderse Vallei Hospital and the Division of Human Nutrition of Wageningen University, was started to formulate a protocol for the treatment of vitamin deficiency and for the maintenance of optimal vitamin D status.
“To discuss the controversies around treatment of deficiency and optimal vitamin D status and intakes, a workshop meeting was organised with clinicians, scientists and dieticians,” noted the team – led by first author Michiel Balvers from Wageningen University.
“We advise using different levels to define deficiency, sufficiency and optimal concentrations of 25(OH)D for different age groups,” wrote Balvers and colleagues.
“Deficiency means that there is insufficient protection against osteomalacia and fractures … An optimal concentration means that there is adequate protection against chronic diseases or conditions with a progressive pathophysiology (for example, fracture risk), and sufficiency includes concentrations between deficiency and optimal 25(OH)D concentrations.”
According to the new advice from NutriProfiel:
- For children aged 0–4 years, 10 μg/d (400 IU/d) would be sufficient, with an optimal 25(OH)D concentration of 30–50 nmol/l.
- For 5–64 years 10–20 μg/d (400–800 IU/d) with an optimal 25(OH)D concentration range of 50–75 nmol/l are recommended.
- For >65 years a daily intake of 20 μg/d (800 IU/d) and an optimal 25(OH)D concentration range of 75–100 nmol/ml are recommended.
“No special recommendations are made for pregnant or lactating women, or individuals with a dark skin type,” said the team.
“Safety should not be an issue with the recommended intakes, and 25(OH)D levels should never exceed 220 nmol/l,” they added.
According to Balvers and his colleagues, vitamin D deficiency should be reversed using a regimen according to a paper by Van Groningen et al, which “can be followed to treat deficiency in adults greater than 18 years old, after which the recommended intake should be enough to maintain serum 25(OH)D levels.”
“The optimal 25(OH)D concentration is the target, and loading is required when the 25(OH)D concentration is below the optimal range,” said the authors – who noted that measurements of 25 (OH)D after 3 and 9 months will determine whether reference 25(OH)D concentrations are reached and if dose adjustment is needed.
For children less than 18 years old, deficiency is treated by loading with 1 μg/d for every 1 nmol/l increase in 25(OH) D that is required to reach the optimal range, after which the maintenance dose is recommended, they said.
Source: Journal of Nutritional ScienceVolume 4, e 23, Pages 1- 8 doi: 10.1017/jns.2015.10“Recommended intakes of vitamin D to optimise health, associated circulating 25-hydroxyvitamin D concentrations, and dosing regimens to treat deficiency: workshop report and overview of current literature”Authors: Michiel Balvers, et al