The effect of feeding patterns on serum zonulin levels in infants at 3-4 months of age.

Zonulin so far is the only known endogenous modulator of intercellular tight junctions which regulate the intestinal permeability. Breastfeeding is considered to enhance the integrity of the gastrointestinal tract; however, limited data are available about the effect of feeding patterns on intestinal permeability. We aimed to investigate the potential association between the mode of feeding (breast versus formula milk) and the serum zonulin levels as a marker of intestinal permeability. One hundred fifty-seven full-term, healthy infants, born after an uncomplicated pregnancy, were enrolled within 72-96 h of life. Blood samples from 105 infants were obtained at 3 to 4 months of life. Serum zonulin levels were measured by ELISA. Out of 105 infants, 52.4% (55) were female, and 58.1% (61) were delivered by caesarian section at a mean gestational age of 38.9 (SD ± 1.0) weeks. At the time of blood sampling, median age was 3.4 (IQR 3.20-3.50) months, and mean weight was 6332 (SD ± 692) gr. Infants were divided in three groups according to the feeding patterns: exclusive breastfeeding (n = 42), mixed feeding (n = 41), and cow's milk formula (n = 22). The feeding pattern had no impact on infants' serum zonulin levels. Moreover, zonulin levels were not affected by infant's clinical and epidemiological characteristics such as body weight or family history of autoimmune disease.Conclusion: In our study, different feeding patterns were not associated with serum zonulin levels in healthy infants at 3-4 months of age. What is Known: • Serum zonulin is upregulated in conditions with increased intestinal permeability • Breast milk favors the physiological decline of the intestinal permeability after birth in the neonates What is New: • Serum zonulin levels were not affected by the feeding pattern (breast milk versus formula) in infants at 3-4 months of age • Clinical and epidemiological characteristics of infants had no impact on zonulin levels.