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.
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.
Lima
Aldo A M
AA
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
Soares
Alberto M
AM
Lima
Noélia L
NL
Mota
Rosa M S
RM
Maciel
Bruna L L
BL
Kvalsund
Michelle P
MP
Barrett
Leah J
LJ
Fitzgerald
Relana P
RP
Blaner
William S
WS
Guerrant
Richard L
RL
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*
D000276:Adjuvants, Immunologic; D015415:Biomarkers; D014815:Vitamins; D014801:Vitamin A; D007781:Lactoferrin