The effect of 38 µg (1500 IU) daily vitamin D3 supplementation, consumed with an Fe-fortified breakfast cereal for 8 weeks, on haematological indicators in Fe-deficient female subjects was investigated. Fifty Fe-deficient subjects (plasma ferritin concentration <20 µg/l; mean age: 27·4 (sd 9·4) years) were randomised to consume an Fe-fortified breakfast cereal containing 9 mg of Fe 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 Fe 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: Hb 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 Hb concentration in the vitamin D group (135 (sd 11) to 138 (sd 10) g/l) was significantly higher compared with the placebo group (131 (sd 15) to 128 (sd 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 (sd 3·0) to 43·8 (sd 3·4) %) compared with the placebo group (41·2 (sd 4·3) to 40·7 (sd 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 Fe-fortified breakfast cereal led to improvement in Hb concentration and haematocrit levels in women with low Fe stores. These findings may have therapeutic implications in the recovery of Fe status in Fe-deficient populations at a healthcare level.
Keywords: 25(OH)D 25-hydroxyvitamin D; HAMP antimicrobial peptide; MCH mean corpuscular Hb; PTH parathyroid hormone; UHT ultra-high temperature; VDBP vitamin D binding protein; sTfR soluble transferrin receptor; Hepcidin; Iron status; Iron-fortified cereals; Vitamin D supplementation.