Evidence of oxidative stress in full-term healthy infants
James K Friel1, Russ W Friesen, Scott V Harding
1Department of Human Nutritional Sciences, University of Manitoba, Winnipeg, Manitoba, Canada R3T 2N2. frielj@ms.umanitoba.ca
Insights
Newborn infants experience oxidative stress due to adapting to oxygen. Levels of lipid peroxidation products decreased, while antioxidant capacity and enzyme activity showed early declines, suggesting potential benefits of antioxidant supplementation.
Area of Science:
- Neonatal physiology
- Biochemistry
- Oxidative stress research
Background:
- Infancy presents unique physiological challenges, including adaptation to atmospheric oxygen.
- Oxidative stress, an imbalance between free radicals and antioxidants, may impact infant development.
- Human milk provides essential nutrients but its role in mitigating early oxidative stress requires investigation.
Purpose of the Study:
- To investigate the hypothesis that early infancy is a period of oxidative stress in term infants fed human milk.
- To quantify markers of oxidative stress and antioxidant status during the first year of life.
Main Methods:
- Longitudinal study of 77 full-term infants fed human milk from birth.
- Measurement of plasma F2-isoprostanes (lipid peroxidation product) at 1, 3.5, 6, and 12 months.
- Assay of plasma ferric reducing ability (FRAP) and red blood cell (RBC) catalase (CAT) and superoxide dismutase (SOD) activities.
Main Results:
- Plasma F2-isoprostanes significantly decreased from 1 to 6 months of age.
- Plasma FRAP showed a declining trend from 1 to 6 months.
- RBC-SOD and RBC-CAT activities exhibited declines between 3.5 and 6 months, with CAT increasing initially.
Conclusions:
- The findings suggest that human infants experience oxidative stress in early infancy.
- Observed changes in antioxidant markers indicate a potential vulnerability during this period.
- Further research into antioxidant supplementation for mothers or infants may be beneficial.
Abstract:
We hypothesized that early infancy would be a time of oxidative stress due to the difficulty of adapting to ambient oxygen. Therefore, we measured levels of products of lipid peroxidation (F2-isoprostanes), antioxidant enzyme activity (catalase (CAT) and superoxide dismutase (SOD)), and ability to resist oxidative stress (ferric reducing ability of plasma (FRAP)) in full-term infants (38-42 wk) fed human milk from birth. Seventy-seven infants were followed at 1, 3.5, 6, and 12 mo of age. F2-isoprostanes in plasma declined significantly (p < 0.05) from 1 to 6 mo (160 +/- 43; 90 +/- 33; 41 +/- 27 pg/mL (mean +/- SD)). FRAP values (775 +/- 196, 723 +/- 133, 697 +/- 126, 669 +/- 145 microM) 1, 3.5, 6, and 12, respectively) declined (p = 0.06) from 1 to 3.5 mo and from 3.5 to 6 mo of age. RBC-SOD (2.7 +/- 2, 3.2 +/- 2.8, 2.1 +/- 1.8, 2.5 +/- 1.8 U, 1, 3.5, 6, 12 mo, respectively) declined from 3.5 to 6 mo. RBC-CAT (76 +/- 23, 94 +/- 28, 81 +/- 22, 85 +/- 31 U, 1, 3.5, 6, 12 mo, respectively) also declined between 3.5 and 6 mo, after a significant increase between 1 and 3.5 mo. These data suggest that the human infant is under oxidative stress early in infancy and further study may be warranted to assess the potential benefits of antioxidant supplementation for either the mother or the infant.
