Related Experiment Video
Updated: Jun 27, 2026

Measuring Lactase Enzymatic Activity in the Teaching Lab
Published on: August 6, 2018
Urinary D-lactate excretion in infants receiving Lactobacillus johnsonii with formula
Elisabeth Haschke-Becher1, Oscar Brunser, Sylvia Cruchet
1Central Laboratory, University Hospital of Neurology, Paracelsus Medical University, Salzburg, Austria. e.haschke-becher@salk.at
Background/Aims:
Supplementation with certain probiotics can improve gut microbial flora and immune function but should not have adverse effects. This study aimed to assess the risk of D-lactate accumulation and subsequent metabolic acidosis in infants fed on formula containing Lactobacillus johnsonii (La1).
Methods:
In the framework of a double-blind, randomized controlled trial enrolling 71 infants aged 4-5 months, morning urine samples were collected before and 4 weeks after being fed formulas with or without La1 (1 x 10(8)/g powder) or being breastfed. Urinary D- and L-lactate concentrations were assayed by enzymatic, fluorimetric methods and excretion was normalized per mol creatinine.
Results:
At baseline, no significant differences in urinary D-/L-lactate excretion among the formula-fed and breastfed groups were found. After 4 weeks, D-lactate excretion did not differ between the two formula groups, but was higher in both formula groups than in breastfed infants. In all infants receiving La1, urinary D-lactate concentrations remained within the concentration ranges of age-matched healthy infants which had been determined in an earlier study using the same analytical method. Urinary L-lactate also did not vary over time or among groups.
Conclusions:
Supplementation of La1 to formula did not affect urinary lactate excretion and there is no evidence of an increased risk of lactic acidosis.
Related Concept Videos
Formation of Dilute Urine
Filtrate Osmolarity in the PCT
Initially, as the filtrate passes through the proximal convoluted tubule (PCT), its...
Formation of Concentrated Urine
Development of Human Microbiota
Drug Dosing: Infants and Children
Filtration and Urine Formation
Pharmacokinetics in Pediatric Patients: Drug Excretion
