It said data was strong enough to back intakes for muscle and skeletal health outcomes like rickets and osteoporosis but not other health benefits. And there was not enough data to recommend levels for lactating women.
EFSA’s Panel on Dietetic Products, Nutrition and Allergies (NDA) used bodily vitamin D levels known as (serum 25(OH)D) as its fundamental measure.
After consideration of factors like exposure to sun (which provokes bodily vitamin D production) the Panel set an adequate intake (AI) level of 15 micrograms (µg) per day from food sources for adults and children to achieve a serum level of 50 nanomoles per litre (nmol / L).
For infants aged 7–11 months, 10 µg / day was established.
After “taking into account the overall evidence and uncertainties” the NDA found that “overall, for adults, infants and children, there is evidence for an increased risk of adverse musculoskeletal health outcomes at serum 25(OH)D concentrations below 50 nmol/L.”
Adverse pregnancy-related health outcomes also increased below the same 50nmol / L level even though it noted the available data is “widely variable”.
The NDA noted the difficulty in establishing vitamin D dietary reference values (DRVs) due to the complex interplay between how much of the ‘sunshine vitamin’ is generated in the body and how much is synthesised from sources like foods and food supplements.
With this in mind it engaged an ‘external contractor’ to perform a meta-regression analysis of “the relationship between serum 25(OH)D concentration and total vitamin D intake (habitual diet, and fortified foods or supplements using vitamin D3).”
This featured 83 trials with children and adults (excluding pregnant or lactating women).
After that it found inadequate evidence to establish Average Requirements (ARs) and Population Reference Intakes (PRIs), but enough data to set Adequate Intakes (AIs) “for all population groups.”
An explanation of different intake measures can be found here.
In sunnier climes the Panel noted “the requirement for dietary vitamin D is lower or may even be zero.”
In the UK, about one in five adults are estimated to have serum levels below 25nmol / L (half the NDA recommendation).
Current UK government advice, replicated in many European nations, states no additional dietary intake of vitamin D is necessary for individuals living a ‘normal lifestyle’.
Rickets, rates of which have been rising in recent years in many countries, causes bones to become soft and weak in children, which can lead to bone deformities.
Vitamin D is a fat-soluble vitamin family encompassing ergocalciferol (vitamin D2) and cholecalciferol (vitamin D3). Both forms are found in foods and supplements, while vitamin D3 is synthesised in the body when skin is exposed to UV light (like the sun).