To evaluate the long-term effect on micronutrient status of a β-carotene-, iron- and iodine-fortified biscuit given to primary school children as school feeding.

Children receiving the fortified biscuit were followed in a longitudinal study for 2.5 years (n=108); in addition, cross-sectional data from three subsequent surveys conducted in the same school are reported.

A rural community in KwaZulu-Natal, South Africa.

Children aged 6–11 years attending the primary school where the biscuit was distributed.

There was a significant improvement in serum retinol, serum ferritin, haemoglobin, transferrin saturation and urinary iodine during the first 12 months of the biscuit intervention. However, when the school reopened after the summer holidays, all variables, except urinary iodine, returned to pre-intervention levels. Serum retinol increased again during the next 9 months, but was significantly lower in a subsequent cross-sectional survey carried out directly after the summer holidays; this pattern was repeated in two further cross-sectional surveys. Haemoglobin gradually deteriorated at each subsequent assessment, as did serum ferritin (apart from a slight increase at the 42-month assessment at the end of the school year).

This study has shown that fortification of a biscuit with β-carotene at a level of 50% of the Recommended Dietary Allowance (RDA) was enough to maintain serum retinol concentrations from day to day, but not enough to sustain levels during the long school holiday break. Other long-term solutions, such as local food production programmes combined with nutrition education, should also be examined. The choice of the iron compound used as fortificant in the biscuit needs further investigation.