Early differences in fecal microbiota composition in children may predict overweight.

Experimental studies suggest that gut microbiota deviations predispose toward energy storage and obesity. We wanted to establish whether early gut microbiota composition can guide weight development throughout early childhood. Overweight and obese children (n = 25) were selected from a prospective follow-up study at the age of 7 y and identified according to the International Obesity Task Force criteria. Normal-weight children (n = 24) were selected from the same cohort and matched for gestational age and body mass index at birth, mode of delivery, probiotic supplementation, duration of breastfeeding, use of antibiotics during infancy, and frequencies of atopic diseases and atopic sensitization. Early fecal microbiota composition was analyzed by fluorescent in situ hybridization (FISH) with microscopic and flow cytometry detection and by quantitative real-time polymerase chain reaction (qRT-PCR). The bifidobacterial numbers in fecal samples during infancy, as assessed by the FISH with flow cytometry, were higher in children remaining normal weight, [median: 2.19 x 10(9) cells/g (interquartile range: 1.10-5.28 x 10(9) cells/g)] than in children becoming overweight [1.20 x 10(9) cells/g (0.48-1.59x 10(9) cells/g); P = 0.02]. A similar tendency was found by FISH with microscopic detection and qRT-PCR. The microbiota aberrancy during infancy in children becoming overweight was also associated with a greater number of Staphylococcus aureus [0.64 x 10(6) cells/g (0.33-1.00 x 10(6) cells/g)] than in children remaining normal weight [0.27 x 10(6) cells/g (0.17-0.50 x 10(6) cells/g); P = 0.013]. Aberrant compositional development of the gut microbiota precedes overweight, offering new possibilities for preventive and therapeutic applications in weight management.