title: Effects of vitamin A supplementation on intestinal barrier function, growth, total parasitic, and specific Giardia spp infections in Brazilian children: a prospective randomized, double-blind, placebo-controlled trial.
abstract: BACKGROUND
  This study evaluates the effects of retinol on intestinal barrier function, growth, total parasites, and Giardia spp infections in children in northeastern Brazil.
  
  
  METHODS
  The study was a double-blind, randomized placebo-controlled trial (http://clinicaltrials.gov; register no. #NCT00133406) involving 79 children who received vitamin A 100,000-200,000 IU (n = 39) or placebo (n = 40) at enrollment, 4, and 8 months and were followed for 36 months. Intestinal barrier function was evaluated using the lactulose:mannitol ratio test. Stool lactoferrin was used as a marker for intestinal inflammation.
  
  
  RESULTS
  The groups were similar with regard to age, sex, nutritional parameters (z scores), serum retinol concentrations, proportion of lactoferrin-positive stool samples, and intestinal barrier function. The lactulose:mannitol ratio did not change during the same time of follow-up (P > 0.05). The proportion of lactoferrin-positive samples evaluated at 1 month did not change between groups (P > 0.05). Total intestinal parasitic, specifically new, infections were significantly lower in the vitamin A treatment compared with control group; these were accounted for entirely by significantly fewer new Giardia infections in the vitamin A treatment group. The cumulative z scores for weight-for-length or height, length or height-for-age z scores, and weight-for-age did not change significantly with vitamin A intervention for 36 months of follow-up.
  
  
  CONCLUSIONS
  These data showed that total parasitic infection and Giardia spp infections were significantly lower in the vitamin A treatment group when compared with the placebo group, suggesting that vitamin A improves the host's defenses against Giardia infections.
authors.affiliation: INCT-Institute of Biomedicine, Clinical Research Unit, Department of Physiology and Pharmacology, School of Medicine, Federal University of Ceará, Fortaleza, Ceará, Brazil. alima@ufc.br
authors.forename: Aldo A M
authors.initials: AA
authors.lastname: Lima
authors.forename: Alberto M
authors.initials: AM
authors.lastname: Soares
authors.forename: Noélia L
authors.initials: NL
authors.lastname: Lima
authors.forename: Rosa M S
authors.initials: RM
authors.lastname: Mota
authors.forename: Bruna L L
authors.initials: BL
authors.lastname: Maciel
authors.forename: Michelle P
authors.initials: MP
authors.lastname: Kvalsund
authors.forename: Leah J
authors.initials: LJ
authors.lastname: Barrett
authors.forename: Relana P
authors.initials: RP
authors.lastname: Fitzgerald
authors.forename: William S
authors.initials: WS
authors.lastname: Blaner
authors.forename: Richard L
authors.initials: RL
authors.lastname: Guerrant
mesh_terms: D000276:Adjuvants, Immunologic / Q000494:pharmacology / Q000627:therapeutic use*; D015415:Biomarkers; D002648:Child; D002675:Child, Preschool; D019587:Dietary Supplements; D004311:Double-Blind Method; D005243:Feces; D005260:Female; D005873:Giardiasis / Q000469:parasitology / Q000517:prevention & control*; D006128:Growth / Q000187:drug effects*; D006801:Humans; D007249:Inflammation / Q000378:metabolism; D007413:Intestinal Mucosa / Q000187:drug effects* / Q000469:parasitology / Q000503:physiopathology; D007781:Lactoferrin / Q000378:metabolism; D008297:Male; D011528:Protozoan Infections / Q000469:parasitology / Q000517:prevention & control; D014801:Vitamin A / Q000494:pharmacology / Q000627:therapeutic use*; D014815:Vitamins / Q000494:pharmacology / Q000627:therapeutic use*
chemical_list: D000276:Adjuvants, Immunologic; D015415:Biomarkers; D014815:Vitamins; D014801:Vitamin A; D007781:Lactoferrin