Vitamin D3 supplementation for 8 weeks leads to improved haematological status following the consumption of an iron-fortified breakfast cereal: a double-blind randomised controlled trial in iron-deficient women.

Abstract

The effect of 38 µg (1500 IU) daily vitamin D3 supplementation, consumed with an iron-fortified breakfast cereal for 8 weeks, on haematological indicators in iron-deficient female subjects was investigated. Fifty iron-deficient subjects (plasma ferritin concentration < 20 µg/L; mean age ± SD: 27.4 ± 9.4 years) were randomised to consume an iron-fortified breakfast cereal containing 9 mg of iron daily, with either a vitamin D3 supplement or placebo. Blood samples were collected at baseline, interim (4 weeks) and post-intervention (8 weeks) for measurement of iron and vitamin D status biomarkers. The effect of intervention was analysed using mixed-model repeated measures ANOVA. Significant increases were observed in two main haematological indices: haemoglobin concentration and haematocrit level from baseline to post-intervention in the vitamin D group, but not in the placebo group. The increase from baseline to post-intervention in haemoglobin concentration in the vitamin D group (135 ± 11 to 138 ± 10 g/L) was significantly higher compared to the placebo group (131 ± 15 to 128 ± 13 g/L) (P=0.037). The increase in haematocrit level from baseline to post-intervention was also significantly higher in the vitamin D group (42.0 ± 3.0 to 43.8 ± 3.4%) compared to the placebo group (41.2 ± 4.3 to 40.7 ± 3.6%) (P=0.032). Despite the non-significant changes in plasma ferritin concentration, this study demonstrates that 38 µg supplemental vitamin D, consumed daily, with iron-fortified breakfast cereal led to improvement in haemoglobin concentration and haematocrit levels in women with low iron stores. These findings may have therapeutic implications in the recovery of iron status in iron-deficient populations at a healthcare level.