title: Inclusion of guava enhances non-heme iron bioavailability but not fractional zinc absorption from a rice-based meal in adolescents.
abstract: Assessing the bioavailability of non-heme iron and zinc is essential for recommending diets that meet the increased growth-related demand for these nutrients. We studied the bioavailability of iron and zinc from a rice-based meal in 16 adolescent boys and girls, 13-15 y of age, from 2 government-run residential schools. Participants were given a standardized rice meal (regular) and the same meal with 100 g of guava fruit (modified) with (57)Fe on 2 consecutive days. A single oral dose of (58)Fe in orange juice was given at a separate time as a reference dose. Zinc absorption was assessed by using (70)Zn, administered intravenously, and (67)Zn given orally with meals. The mean hemoglobin concentration was similar in girls (129 ± 7.8 g/L) and boys (126 ± 7.1 g/L). There were no sex differences in the indicators of iron and zinc status except for a higher hepcidin concentration in boys (P < 0.05). The regular and modified meals were similar in total iron (10-13 mg/meal) and zinc (2.7 mg/meal) content. The molar ratio of iron to phytic acid was >1:1, but the modified diet had 20 times greater ascorbic acid content. The absorption of (57)Fe from the modified meal, compared with regular meal, was significantly (P < 0.05) greater in both girls (23.9 ± 11.2 vs. 9.7 ± 6.5%) and boys (19.2 ± 8.4 vs. 8.6 ± 4.1%). Fractional zinc absorption was similar between the regular and modified meals in both sexes. Hepcidin was found to be a significant predictor of iron absorption (standardized β = -0.63, P = 0.001, R(2) = 0.40) from the reference dose. There was no significant effect of sex on iron and zinc bioavailability from meals. We conclude that simultaneous ingestion of guava fruit with a habitual rice-based meal enhances iron bioavailability in adolescents.
authors.affiliation: Divisions of Micronutrient Research, National Institute of Nutrition, Indian Council of Medical Research, Hyderabad, India. nairthayil@gmail.com
authors.forename: Krishnapillai Madhavan
authors.initials: KM
authors.lastname: Nair
authors.forename: Ginnela N V
authors.initials: GN
authors.lastname: Brahmam
authors.forename: Madhari S
authors.initials: MS
authors.lastname: Radhika
authors.forename: Roy Choudhury
authors.initials: RC
authors.lastname: Dripta
authors.forename: Punjal
authors.initials: P
authors.lastname: Ravinder
authors.forename: Nagalla
authors.initials: N
authors.lastname: Balakrishna
authors.forename: Zhensheng
authors.initials: Z
authors.lastname: Chen
authors.forename: Keli M
authors.initials: KM
authors.lastname: Hawthorne
authors.forename: Steven A
authors.initials: SA
authors.lastname: Abrams
mesh_terms: D000042:Absorption; D000293:Adolescent; D023181:Antimicrobial Cationic Peptides / Q000097:blood; D001682:Biological Availability; D004032:Diet; D005260:Female; D005638:Fruit; D006454:Hemoglobins / Q000032:analysis; D064451:Hepcidins; D006801:Humans; D007503:Iron Isotopes; D019266:Iron, Dietary / Q000493:pharmacokinetics*; D008297:Male; D009752:Nutritional Status; D012275:Oryza / Q000737:chemistry*; D031647:Psidium; D012737:Sex Factors; D015032:Zinc / Q000493:pharmacokinetics*; D015033:Zinc Isotopes
chemical_list: D023181:Antimicrobial Cationic Peptides; C578702:HAMP protein, human; D006454:Hemoglobins; D064451:Hepcidins; D007503:Iron Isotopes; D019266:Iron, Dietary; D015033:Zinc Isotopes; D015032:Zinc