Modeling Vitamin D Fortification Scenarios for the Australian Population

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/d). Increasing the dietary supply of vitamin D could improve vitamin D status across the population.

We modeled 4 vitamin D fortification scenarios to support useful and safe fortification strategies for Australia.

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 modeled 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). Scenarios 2-4 modeled the addition of vitamin D to edible oil spreads and fluid milk/alternatives at higher concentrations than permitted and the addition of the maximum permitted amount to scenario 2, dairy products/alternatives other than fluid milk, formulated beverages; scenario 3: scenario 2 plus eligible ready-to-eat breakfast cereals; scenario 4: scenario 3 plus bread (not permitted for vitamin D fortification in Australia). We used the National Cancer Institute method to model the 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 (10 μg/d) and the Australian upper level of intake (80 μg/d).

Under scenarios 1-4, respectively, the projected proportion of Australians with vitamin D intake <10 μg/d was 80%, 84%, 73%, and 60%. No participant exceeded the upper level of intake under any scenario.

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.