Comparison of food habits, iron intake and iron status in adolescents before and after the withdrawal of the general iron fortification in Sweden

Abstract

Background/objectives: Sifted flour was fortified with carbonyl iron for 50 years in Sweden. This study evaluates changes in food habits, intake of iron, factors affecting iron absorption and iron status after the discontinuation of the general iron fortification in adolescents with the highest requirements.

Subjects/methods: A total of 2285 15- to 16-year-old students in 1994 (634 girls and 611 boys) and in 2000 (534 girls and 486 boys) in 13 schools in Gothenburg, Sweden, were included in two cross-sectional surveys assessing food habits with diet history interviews and iron deficiency defined with serum ferritin stores ⩽ 15 μg/l and no preceding infection.

Results: In girls, iron deficiency increased from 37 to 45%, while in boys, it was stable at 23%. Total iron intake decreased from 15.7 to 9.5 mg/day and 22.5 to 13.9 mg/day in girls and boys, respectively. Cereals were the main iron source. Among girls, the increase of fish and decrease of calcium intake may not counteract the effect of decreased intake of fortification iron. Among boys, more meat, less calcium and more vitamin C may have favoured the bioavailability of iron.

Conclusions: The discontinuation of the general iron fortification resulted in a 39% decrease in total iron intake and iron deficiency increased substantially in girls. However, in boys no change in iron deficiency was observed. Whether this was a result of changed bioavailability of dietary iron or simultaneous changes of non-dietary factors remains to be explored.