The Impact of Vitamin B12 Deficiency on Infant Gut Microbiota

Vitamin B12 plays important roles in DNA synthesis and neurological functions. Vitamin B12 deficiency is one of the most common micronutrient deficiencies and it has become increasingly more frequent in infants. The deficiency develops more often between 4 to 12 months of age, coinciding with the decreased fetal storage. The highest rates of vitamin B12 deficiency were observed among infants who are breastfed by mothers receiving a diet low in vitamin B12. The main objective of this study is to compare the gut microbial composition of healthy term exclusively breastfed infants with or without vitamin B12 deficiency. We hypothesized that gut microbiome differs between vitamin B12 deficient and control infants; pathogenic bacteria are hypothesized to be higher, and beneficial bacteria to be lower in vitamin B12 deficient infants as compared to control. An observational study in the Marmara University Pendik Research and Training Hospital well child outpatient clinic is conducted in 90 infants. Participants aged between 4 to 6 months who fulfill the inclusion criteria are enrolled. Inclusion criteria are term birth (\>37 gestational weeks), birth weight \>2500 gr, absence of congenital anomalies, hemoglobin ≥10 g/dL, and exclusive breastfeeding. Exclusion criteria include prematurity, low birth weight, intrapartum antibiotic use, current or previous use of infant formula, malnutrition, use of iron supplements, infant use of antibiotics, use of probiotics within the last 8 weeks before study entry, and introduction to solid foods. Primary outcome measures:Microbial counts, and a comparison of type and abundance of species (predominant, pathogenic, and opportunistic bacteria, yeast, and parasites) between vitamin B12 deficient and sufficient subjects will be assessed. Secondary outcome measures: Fecal bacterial communities will be assessed before and after treatment in a subgroup of infants. Each stool sample is collected from cloth diapers, and placed in sterile