Effect of neonatal administration of Lactiplantibacillus plantarum ATCC 202195 on stool iron content and iron status in infants in Dhaka, Bangladesh

BackgroundProbiotics may enhance host iron bioavailability, offering a strategy to address iron deficiency. Fecal iron may be a useful non-invasive biomarker of such effects in infants. ObjectiveTo examine the use of fecal iron quantification in a randomized placebo-controlled trial (RCT) of neonatal administration of Lactiplantibacillus plantarum ATCC 202195 (LP202195), with or without fructooligosaccharide (FOS), in Dhaka, Bangladesh. MethodsFecal iron quantification using atomic absorption spectrometry (AAS) was optimized using standards and reference materials, and pilot-tested using pooled stool aliquots (n=32) from an observational cohort of young infants in Bangladesh (aged 0-64 days). The optimized AAS assay was then applied to individual stool samples collected at 14 days of age (n=307) in a RCT in which newborns aged 0-4 days were randomly allocated to one of five groups: placebo, 1-or 7-day regimens of LP202195, with or without FOS. Serum ferritin was measured at 2 months postnatal age (n=251). Effects of the 1-and 7-day LP202195 regimens were estimated using linear regression and expressed as mean percent differences relative to placebo, with 95% confidence intervals (95%CI). ResultsThe optimized AAS fecal iron assay had acceptable accuracy (91-99%), precision (within-and between-run coefficients of variation <10%), and recovery (93-112%), with a reportable range of 0.2 to 80 mg Fe per 100 g dry stool. In pooled samples from the observational cohort, fecal iron varied with age and feeding status. In the RCT, fecal iron concentrations did not significantly differ following1-day (% difference=9.8%, 95%CI:-19%, 49%; P=0.54) or 7-days (% difference=-6.1%, 95%CI:-31%, 28%; P=0.69) of LP202195 administration, versus placebo (geometric mean concentration=4.3mg Fe/100g dry stool (95%CI:3.3, 5.6); n=53). Inferences were unchanged when groups were disaggregated by FOS co-administration (P>0.05 for all). Similarly, there were no effects of LP202195 on serum ferritin at 2 months of age (P>0.05 for all). ConclusionsFecal iron quantification by AAS was valid and feasibly implemented in a trial of neonatal administration of Lactiplantibacillus plantarum ATCC 202195. However, the assay is resource-intensive and may not be more informative than conventional measures of iron status when studying the effects of probiotics/synbiotics on iron bioavailability. Clinical Trial RegistryClinicalTrials.gov identifier: NCT05180201