Impact of vitamin A supplementation on anaemia and plasma erythropoietin concentrations in pregnant women: a controlled clinical trial

Introduction: Although studies suggest that vitamin A or its metabolites in fluence the synthesis of erythropoietin in vitro and in animal models, it i s unclear whether vitamin A supplementation increases plasma erythropoietin concentrations in humans. Objective: To determine whether daily vitamin A supplementation increases plasma erythropoietin concentrations in pregnant women with a high prevalence of anaemia. Methods: A randomized, double-blin d, controlled clinical trial was conducted to examine the effect of daily v itamin A (3000 tg retinol equivalent), iron (30 mg), and folate (400 mug) v ersus iron (30 mg) and folate (400 tg) (control) on haemoglobin and plasma erythropoietin concentrations in 203 pregnant women in Malawi, Africa. Resu lts: Mean gestational age at enrollment was 23 wk, at which time 50% of the women were anaemic (haemoglobin < 110 g/L). Mean ( SEM) change in haemoglo bin from enrollment to 38 wk was 4.7 +/- 1.6 g/L (p = 0.003) and 7.3 +/- 2. 3 g/L (p = 0.003) in the vitamin A and control groups, respectively. Mean c hange in plasma erythropoietin concentrations from enrollment to 38 wk was 2.39 +/-5.00 (p=0.63) and -2.87 +/-3.92 IU/L (p = 0.46) in the vitamin A an d controls groups, respectively. There were no significant differences betw een vitamin A and control groups in the slope of the regression line betwee n log(10) erythropoietin and haemoglobin at enrollment or 38 wk, and betwee n enrollment and follow-up within either group. Conclusions: Vitamin A supp lementation does not appear to increase haemoglobin and plasma erythropoiet in concentrations among pregnant women with a high prevalence of anaemia in Malawi.