Iron‐fortified and unfortified cow's milk: Effects on iron intakes and iron status in young children

Abstract

Iron intakes and iron status were evaluated in 36 young Swedish children given either iron-fortified or unfortified cow's milk. All children had good iron status and had received breast milk or iron-fortified formulae during infancy. Twenty 1-y-old children were randomized to a diet with iron-fortified milk (7.0 or 14.9 mg Fe l(-1) and 16 to a diet with unfortified milk. The iron intakes in the unfortified group at 15 and 18 mo (mean +/- SD 5.19 +/- 2.29 and 5.84 +/- 1.62 mg d(-1)) were low in relation to Nordic Nutrition Recommendations, while the intakes in the iron-fortified group (10.20 +/- 2.60 and 10.87 +/- 2.79mg d(-1)) were normal in relation to recommendations. The gain (increase) from receiving fortified diet during the study period was at most [upper limit for 95% confidence interval (CI)] 2.6 g l(-1) in blood haemoglobin, 1.9 fl in mean corpuscular volume, 2.7 micromol in serum iron and 4.5% in transferrin iron saturation, and the gain (decrease) was at most (lower limit for 95% CI) 0.29g l(-1) in serum transferrin and 0.9mg l(-1) in serum transferrin receptor (TfR). None of these differences was statistically significant. There was an almost significantly higher increase in serum ferritin (1.4 times higher relation of values at the end compared with the beginning, p = 0.06) and a significantly higher (1.2; p = 0.047) decrease in TfR/ log10 ferritin ratio in the fortified group. One-year-old children starting out with good iron status given either iron-fortified or unfortified cow's milk from 12 to 18 mo maintain sufficient iron status during this period. However, children fed unfortified cow's milk have an iron intake which is low in relation to recommendations and the quantitative development of their reserve iron in iron stores seems to be weaker than that of the fortified group. The consequences of this require further study.