PROOXIDANT EFFECTS OF MATERNAL SMOKING AND FORMULA IN NEWBORN-INFANTS

Background: The purpose of this study was to use the breath ethane tes t to determine if either maternal cigarette smoking, formula, and/or d eficiency of the antioxidant nutrients vitamins A and E was associated with oxidant stress in newborn infants. The rationale for this study was: (1) our observation that cigarette smoking was a source of oxidan t stress in pregnant women, suggesting that it could be a source of ox idant stress for infants exposed in utero; (2) formula was predicted t o be prooxidant compared to colostrum, which contains several compound s with antioxidant activity in vitro; and (3) deficiencies of vitamins A and E have been shown to promote oxidant stress in experimental ani mals. Methods: Breath ethane, a volatile alkane produced by peroxide o f n-3 fatty acids, was utilized as an index of oxidant stress status. Forty-five healthy full-term infants of the women mentioned above were studied at 18-24 h of age, after four to six feedings of breast milk (colostrum) or casein-based infant formula. Relationships between infa nt breath ethane, maternal smoking, mode of infant nutrition, and seru m concentrations of the antioxidant vitamins A and E of infants were e xamined. Results: The breath ethane of the entire group of infants who se mothers smoked (n=19) was increased compared to values of infants w hose mothers did not smoke (n=26): 97+/-16 versus 43+/-9 pmol/kg/min, p <0.03. When infants of mothers who smoked were eliminated from the a nalysis in order to study effects of nutrition alone, formula appeared to be prooxidant compared to breast milk. Breath ethane of formula-fe d infants (n=16) was 62+/-13 versus 13+/-4 pmol/kg/min for breast-fed infants (n=10), p <0.04. For the group as a whole, there was no correl ation between infant breath ethane and serum concentrations of vitamin s A and E. Conclusions: Exposure to maternal smoking in utero is proox idant in newborn infants. Formula also has a prooxidant effect compare d to colostrum in newborn infants not exposed to maternal smoking in u tero. Further investigations will be necessary to explore the clinical consequences of these observations.