Evaluation of breast milk total antioxidant capacity (TAC) levels in third and fourth months of lactation
Background: In addition to numerous clinically significant aspects of breastfeeding,it seems breast milk contains antioxidant molecules that can help prevent oxidative stress situations. The aim of this study was to determine breast milk total antioxidant capacity (TAC) levels in third months of lactation. Methods: In this study,50 lactating mothers who exclusively breastfed their infants for 90 days were recruited from health centers. Information on food intake was collected by using a 24- hour recall method for 3 days and the body mass index (BMI) was calculated. Breast milk samples (15 mL) were collected into sterile glass bottles by self-expression before the baby was nursed in the morning in thirds and fourth months of lactation and stored at - 70°C until analysis. Breast milk TAC level was measured using a Randox total antioxidant status kit The comparison between the two periods was made by ANCOVA test. p value of < 0.05 was considered statistically significant. Results: The mean antioxidant concentration of breast milk in third and fourth months of lactation was 0.315 ± 0.14 and 0.253 ±0.13 mmol/l respectively. After adjusting for maternal BMI,energy,macronutrients,and vitamin A,E,and C,zinc,and selenium intake,a significant reduction was observed in breast milk TAC levels between the two months (P= 0.02). Conclusions: Breast milk TAC level was significantly lower than reported values from Japan and Nigeria. This discrepancy in TAC values between studies may be due to maternal diet and supplementation with vitamins during pregnancy and lactation,time of year during which the milk samples were collected,ethnic group and the geographical area to which the mother belongs,and analyzing methods. Also,derived from our results,TAC of breast milk tends to level off with the passage of time which can be a natural result of decline in antioxidant storage of the mothers. However further studies are needed to make concise conclusions.