Objective: To examine if zinc food fortification makes a significant contribution to dietary zinc intake and to describe zinc-fortified food usage, amongst Canadian preschoolers.
Methods: Cross-sectional data were used from the NutriSTEP validation project for which preschoolers (3-5 years) from across Ontario were recruited using convenience sampling. Three-day food records were used to estimate mean daily zinc intake and children were stratified by age group for analysis. Comparisons were then made to the Dietary Reference Intakes, whilst accounting for zinc from zinc-fortified foods and supplements and also whilst excluding zinc from zinc-fortified foods, to determine the prevalence of inadequate (< Estimated Average Requirement (EAR)) and excessive (> Tolerable Upper Intake Level (TUL)) zinc intakes. The contributions (%) made to total zinc intake by zinc-fortified foods, unfortified foods and zinc-containing supplements were determined as were contributions made to zinc intake by zinc-fortified foods, categorized by fortified-food type.
Results: Fewer than a third (30%, n = 76) of participants ate zinc-fortified foods and only 3% (n = 7) used a zinc-containing supplement. Including the contribution from zinc-fortified foods, 25% (n = 32) of 3-year-olds (n = 128) had mean zinc intake (range 7.0-7.6 mg/day) marginally above the TUL (7 mg/day). Zinc-fortified foods contributed only 2.3 +/- 5.8% (mean% +/- SD) to total zinc intake. The mean intake of the 25% of 3-year-olds above the TUL is attributed to their higher mean energy and protein intakes (p < 0.001) as compared to 3-year-olds not consuming zinc at levels above the TUL. Even excluding zinc-fortified foods, the prevalence of inadequate zinc intakes (<EAR) (n = 254) was zero. Fortified breakfast cereals contributed most (77 +/- 41%) (mean% +/- SD) to zinc intake derived from zinc-fortified foods.
Conclusions: Overall, zinc-fortified foods and supplements contributed minimally to the total dietary zinc intake amongst these preschoolers. These children did not have inadequate intakes of zinc and intakes in excess of the TUL were only evident in the youngest age group. Food fortification and parental choice to use a multivitamin-mineral supplement did not appear to play a role in either preventing inadequate or causing excessive zinc intake.