title: Pro- and prebiotic supplementation induces a transient reduction in hemoglobin concentration in infants.
abstract: OBJECTIVE
  : Regarding safety, we investigated the effect of prenatal probiotic and 6 months of pro- and prebiotic supplementation of infants on their hematologic values at 6 months and 2 years and factors affecting these values.
  
  
  METHODS
  : In a prospective randomized controlled probiotic intervention trial in infants at high risk for allergy, we obtained blood samples consecutively from 98 infants at 6 months and from 658 children at 2 years to measure hematologic values. We collected fecal samples at 3 and 6 months to measure immunologic development by calprotectin, alpha-1-antitrypsin, tumor necrosis factor-alpha, and immunoglobulin A.
  
  
  RESULTS
  : At 6 months, infants in the probiotic group had significantly lower hemoglobin (Hb) values than did the placebo group, mean (SD): 119.8 g/L (6.3) versus 123.3 g/L (8.4), P = 0.025. Adjustment for factors that might affect Hb values (breast-feeding duration, solid-food introduction, and sex), revealed no need for adjustment. A significant negative correlation emerged between Hb values at 6 months and fecal calprotectin at age 3 months r = -0.301, P = 0.009, which was affected neither by breast-feeding, sex, nor study group. At 2 years, hematologic values in both groups became similar.
  
  
  CONCLUSIONS
  : Probiotics cause a gut mucosal inflammation with decreased Hb values during intervention, corrected after halting the supplementation.
authors: Skin and Allergy Hospital, Finland. mikael.kuitunen@hus.fi
authors: Mikael
authors: M
authors: Kuitunen
authors: Kaarina
authors: K
authors: Kukkonen
authors: Erkki
authors: E
authors: Savilahti
mesh_terms: D000328:Adult; D002675:Child, Preschool; D005243:Feces / Q000737:chemistry; D005260:Female; D006454:Hemoglobins / Q000378:metabolism*; D006801:Humans; D006967:Hypersensitivity; D007223:Infant; D039841:Leukocyte L1 Antigen Complex / Q000378:metabolism*; D056692:Prebiotics; D011247:Pregnancy; D011295:Prenatal Care / Q000379:methods*; D019936:Probiotics / Q000009:adverse effects*; D011446:Prospective Studies
chemical_list: D006454:Hemoglobins; D039841:Leukocyte L1 Antigen Complex; D056692:Prebiotics