Supplementation with iron and riboflavin enhances dark adaptation response to vitamin A-fortified rice in iron-deficient, pregnant, nightblind Nepali women

• Published in: The American journal of clinical nutrition 2007-05, Vol.85 (5), p.1375-1384
• Main Authors: Graham, Joanne M, Haskell, Marjorie J, Pandey, Pooja, Shrestha, Ram K, Brown, Kenneth H, Allen, Lindsay H
• Format: Article
• Language: English
• Subjects: Adaptation, Physiological; Adult; Anemia, Iron-Deficiency - drug therapy; Anemia, Iron-Deficiency - epidemiology; Biological and medical sciences; blood chemistry; dark adaptation; Dark Adaptation - drug effects; deficiency diseases; Dietary Supplements; erythrocytes; Feeding. Feeding behavior; Female; Food, Fortified; fortified foods; Fundamental and applied biological sciences. Psychology; Humans; iron; Iron Deficiencies; Iron, Dietary - pharmacology; Iron, Dietary - therapeutic use; Nepal; night blindness; Night Blindness - blood; Night Blindness - drug therapy; Night Blindness - epidemiology; nutrient deficiencies; nutrient-nutrient interactions; Oryza; Oryza sativa; photoreceptors; Pregnancy; Pregnancy Complications - blood; Pregnancy Complications - drug therapy; Pregnancy Complications - epidemiology; riboflavin; Riboflavin - pharmacology; Riboflavin - therapeutic use; Riboflavin Deficiency - blood; Riboflavin Deficiency - drug therapy; Riboflavin Deficiency - epidemiology; rice; staple foods; Treatment Outcome; Vertebrates: anatomy and physiology, studies on body, several organs or systems; vitamin A; Vitamin A - pharmacokinetics; Vitamin A - therapeutic use; Vitamin B Complex - pharmacology; Vitamin B Complex - therapeutic use; vitamin-mineral supplements; women
• ISSN: 0002-9165; 1938-3207
• DOI: 10.1093/ajcn/85.5.1375

Background:Nightblindness affects 16-52% of pregnant women in areas of Nepal and in some cases persists after vitamin A treatment. Iron and riboflavin affect vitamin A utilization and photoreceptor function, respectively, and pilot data in the study population showed a high prevalence of iron and riboflavin deficiencies. Objective:The objective was to assess the effect of supplemental iron and riboflavin on pupillary threshold (PT) and plasma retinol in nightblind, pregnant Nepali women given vitamin A-fortified rice. Design:Nightblind pregnant women were randomly assigned to receive, 6 d/wk under supervision for 6 wk, a vitamin A-fortified rice curry dish providing 850 μg retinal activity equivalents/d with either a 30-mg Fe and 6-mg riboflavin (FeR + VA) capsule or a placebo control (VA only) capsule. Hemoglobin, erythrocyte riboflavin, and plasma ferritin and retinol were measured before and after the intervention. Dark adaptation was assessed by PT score. Results:Women who were iron deficient at baseline (n = 38) had significantly greater improvement in PT score with iron and riboflavin supplementation than without (P = 0.05). Iron and riboflavin supplements significantly reduced the prevalences of riboflavin deficiency (from 60% to 6%; P < 0.0001), iron deficiency anemia (from 35% to 15%; P < 0.007), and abnormal PT (from 87% to 30%; P < 0.05) from baseline. Mean increases in erythrocyte riboflavin (P < 0.0001) and plasma ferritin (P = 0.01) were greater in the FeR + VA group than in the VA only group. Conclusion:Iron deficiency may limit the efficacy of vitamin A to normalize dark adaptation in pregnant Nepali women. Further studies are needed to assess the effect of simultaneous delivery of iron and vitamin A for the treatment of nightblindness.