title: Effect of vitamin A and zinc supplementation on gastrointestinal parasitic infections among Mexican children.
abstract: OBJECTIVE
  Gastrointestinal parasites continue to be an important cause of morbidity and stunting among children in developing countries. We evaluated the effect of vitamin A and zinc supplementation on infections by Giardia lamblia, Ascaris lumbricoides, and Entamoeba histolytica.
  
  
  METHODS
  A randomized, double-blind, placebo-controlled trial was conducted among 707 children who were 6 to 15 months of age and from periurban areas of Mexico City, Mexico, between January 2000 and May 2002. Children, who were assigned to receive either vitamin A every 2 months, a daily zinc supplement, a combined vitamin A and zinc supplement, or a placebo, were followed for 1 year. The primary end points were the 12-month rates and durations of infection for the 3 parasites and rates of parasite-associated diarrheal disease as determined in stools collected once a month and after diarrheal episodes.
  
  
  RESULTS
  G. lamblia infections were reduced and A. lumbricoides infections increased among children in the combined vitamin A and zinc group or the zinc alone group, respectively. Durations of Giardia infections were reduced among children in all 3 treatment arms, whereas Ascaris infections were reduced in the vitamin A and zinc group. In contrast, E. histolytica infection durations were longer among zinc-supplemented children. Finally, E. histolytica- and A. lumbricoides-associated diarrheal episodes were reduced among children who received zinc alone or a combined vitamin A and zinc supplement, respectively.
  
  
  CONCLUSIONS
  We found that vitamin A and zinc supplementation was associated with distinct parasite-specific health outcomes. Vitamin A plus zinc reduces G. lamblia incidence, whereas zinc supplementation increases A. lumbricoides incidence but decreases E. histolytica-associated diarrhea.
authors.affiliation: Department of Nutrition, Harvard School of Public Health, Boston, Massachusetts, USA. k.long@uq.edu.au
authors.forename: Kurt Z
authors.initials: KZ
authors.lastname: Long
authors.forename: Jorge L
authors.initials: JL
authors.lastname: Rosado
authors.forename: Yura
authors.initials: Y
authors.lastname: Montoya
authors.forename: Maria
authors.initials: M
authors.lastname: de Lourdes Solano
authors.forename: Ellen
authors.initials: E
authors.lastname: Hertzmark
authors.forename: Herbert L
authors.initials: HL
authors.lastname: DuPont
authors.forename: Jose Ignacio
authors.initials: JI
authors.lastname: Santos
mesh_terms: D000818:Animals; D001196:Ascariasis / Q000188:drug therapy; D017164:Ascaris lumbricoides; D002648:Child; D003967:Diarrhea / Q000188:drug therapy / Q000469:parasitology; D019587:Dietary Supplements; D004311:Double-Blind Method; D004359:Drug Therapy, Combination; D004749:Entamoebiasis / Q000188:drug therapy; D005873:Giardiasis / Q000188:drug therapy; D006801:Humans; D007411:Intestinal Diseases, Parasitic / Q000188:drug therapy*; D008800:Mexico; D014131:Trace Elements / Q000627:therapeutic use*; D014801:Vitamin A / Q000627:therapeutic use*; D014815:Vitamins / Q000627:therapeutic use*; D015032:Zinc / Q000627:therapeutic use*
chemical_list: D014131:Trace Elements; D014815:Vitamins; D014801:Vitamin A; D015032:Zinc