Determining the micronutrient contents infortified foods depends not only on the health goal (additional intake to complement the diet), but also on ensuring that fortification does not raise micronutrient intakes beyond the Tolerable Upper Intake Level (UL), i.e., the safe limit. Technological incompatibility and cost may also restrict the fortification contents. For folic acid, the limiting factor is safety, while for vitamin B-12, it is cost. However, adequate fortification contents that are both safe and efficacious can be estimated for both nutrients. In order to obtain the maximum benefit from the fortification programs, three different formulas responding to three categories Of consumption, as specified by the median and 95th percentile of consumption, are proposed. The model presented is based on the estimation of a Feasible Fortification Level (FFL), which then is used to determine the average, minimum, and maximum contents of the nutrients during production, taking into consideration the acceptable variation of the fortification process. Finally, the regulatory parameters, which support standards and enforcement, are calculated by reducing the proportion of the nutrient that is degraded during the usual marketing process of the fortified food. It is expected that this model will establish a common standard for food fortification, and improve the reliability and enforcement procedures of these programs. The model was applied to flours as vehicles for folic acid in the United States, Guatemala, and Chile. Analysis of the data revealed that, with the exception of Chile, where wheat flour consumption is very high and probably within a narrow range, supplementation with folic acid is still needed to cover individuals at the low end of consumption. This is especially true when the difference in flour consumption is too wide, as in the case of Guatemala, where the proportional difference between consumption at the 95th percentile of the nonpoor group is as high as 100 times the consumption at the 5th percentile of the extremely poor group. Adoption of fortification content for staple foods near the safe limit brings together the need of restricting the voluntary addition of the specific nutrient to other foods and to dietary supplements.
