Modelling vitamin D fortification scenarios for the Australian population.

Abstract

Background: Low vitamin D status (circulating 25-hydroxyvitamin D concentration <50 nmol/L) is prevalent in Australia, and 95% of Australians have been estimated to have low vitamin D intake (mean range 1.8-3.2 μg/day). Increasing the dietary supply of vitamin D could improve vitamin D status across the population.

Objective: We modelled four vitamin D fortification scenarios to support useful and safe fortification strategies for Australia.

Methods: We used cross-sectional food consumption data from the 2011-2012 National Nutrition and Physical Activity Survey (n = 12,153 aged 2-85 y) and analytical food composition data. Scenario 1 modelled the systematic addition of the maximum permitted amount of vitamin D to all foods for which vitamin D fortification is mandated (edible oil spreads) or optional (dairy products/plant-based alternatives, formulated beverages, permitted ready-to-eat breakfast cereals (RTEBC)). Scenarios 2-4 modelled the addition of vitamin D to edible oil spreads and fluid milk/alternatives at higher concentrations than permitted, and addition of the maximum permitted amount to: Scenario 2) dairy products/alternatives other than fluid milk, formulated beverages; Scenario 3) Scenario 2 plus eligible RTEBC; Scenario 4) Scenario 3 plus bread (not permitted for vitamin D fortification in Australia). We used the National Cancer Institute method to model usual intake of vitamin D for each scenario by sex and age group. Dietary adequacy and safety were assessed using the North American Estimated Average Requirement (EAR, 10 μg/day) and the Australian Upper Level of Intake (UL, 80 μg/day).

Results: Under Scenarios 1-4, respectively, the projected proportion of Australians with vitamin D intake <10 μg/day was 80, 84, 73 and 60%. No participant exceeded the UL under any scenario.

Conclusions: A systematic fortification strategy could support a nutritionally meaningful improvement in vitamin D intake across the Australian population. An optimal strategy would require amendments to the Australia New Zealand Food Standards Code.