Types and Levels of Micronutrients to use

The minimum nutrients recommended for flour are iron and folic acid. However, for both wheat and maize flours a combination of some or all of the following nutrients can be added: vitamin A, vitamins B1, B2, B3, B6, B12, folic acid, vitamin D, iron, zinc and calcium.

It is generally recommended that only those vitamins and minerals for which there is a clear and demonstrated need by the population consuming the flour should be added.

Decisions regarding the types and levels of nutrients to be added depend on a number of factors, including:

• government standards (mandatory or voluntary);
• purpose of the program;
• type of fortification program (open market, mass or targeted);
• extraction level of the flour
• Upper level quality constraints: Due to effects on color, taste, smell or baking characteristics, there may be a maximum level of a particular nutrient that can be added without adversely affecting product quality or acceptability. Iron, zinc and riboflavin levels are most likely to be affected by this consideration.
• Upper level safety constraints. The amount of a nutrient added should not exceed established safe upper levels.
• Costs (Vitamin A, for example, is considerably more expensive than the B-vitamins. Calcium, vitamin C, magnesium, biotin, vitamin E and pantothenic acid are also expensive); and
• trade harmonization (to comply with existing trade agreements, countries may need to adopt fortification standards similar to those in other countries in the region).

The WHO Guidelines on Food Fortification, Annex D [pp294-312], provides a detailed procedure for estimating feasible fortification levels for a mass fortification program, including flour fortification.