Submitted to: American Journal of Clinical Nutrition
Publication Type: Peer reviewed journal
Publication Acceptance Date: 1/2/2007
Publication Date: 5/15/2007
Citation: Graham, J.M., Haskell, M.J., Pandey, P., Peerson, J.M., Shrestha, R.K., Brown, K.H., Allen, L.H. 2007. Supplementation with iron and riboflavin enhances dark adaptation response to vitamin A-fortified rice in iron-deficient, pregnant, night-blind Nepali women. American Journal of Clinical Nutrition. 85:1375-1384 Interpretive Summary:
Technical Abstract: Background: Night-blindness (XN) affects 16-52% of pregnant women in parts of Nepal and is not always cured with vitamin A treatment. Iron and riboflavin act in vitamin A utilization and photoreceptor function, respectively, and pilot data in this population showed high prevalence of these deficiencies. Objective: Whether supplemental iron plus riboflavin, in addition to vitamin A, improve pupillary response threshold (PRT) and plasma retinol more than vitamin A alone in XN, pregnant Nepali women. Design: Participants reporting XN were randomized to receive 30 mg Fe + 6 mg riboflavin (FeR) or a placebo-control capsule 6 d/wk under supervision for 6 wk, plus vitamin A-fortified Ultra-rice' (UR) providing 0.85 mg RE/d. Hemoglobin, erythrocyte riboflavin (ER), and plasma ferritin and retinol were measured before and after the intervention. Dark adaptation was assessed by PRT. Results: Mean changes in ER (p<0.001) and plasma ferritin (p<0.005) were greater in the FeR + UR compared to UR only group. Treatment with FeR + UR significantly reduced prevalences of riboflavin deficiency (60 to 6%) and iron deficiency anemia (35 to 15%), and of abnormal PRT from baseline (P < 0.05). Among women with iron deficiency at baseline, there was a trend towards greater improvement in PRT score after supplementation with FeR + UR than UR only (-1.41 ± 0.20 vs. -0.65 ± 0.25 log cd/m2, respectively, p = 0.08). Conclusions: Iron deficiency limits PRT response of Nepali pregnant women and efficacy of vitamin A to treat XN. Further studies providing riboflavin, iron, or iron plus riboflavin are needed to understand the separate and combined roles of these nutrients in dark adaptation.