Human milk from healthy women contains numerous nutrients such as antioxidants which are necessary for newborns. The aim of this study was to evaluate the changes of total antioxidant capacity (TAC) and free radical scavenging activity in human milk during the first six month period of lactation and also its relationship to maternal plasma. A total of 505 milk samples (colostrum, transitional and mature milks) collected from 115 healthy women with full term newborns. Blood plasma was obtained from 58 women at 3 months postpartum. The TAC of samples were measured by Ferric Reducing/Antioxidant Power assay and free radical scavenging activity were evaluated using 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals. TAC was obviously higher in colostrums than transitional and mature milks. Similar results were observed for DPPH radical scavenging activity of the samples. There was a high significant correlation between the results of these two methods. The relationship between the antioxidant content of human milk and maternal plasma was also significant. These data suggest that using colostrum, with high antioxidant potential during the first days of life is vital; moreover, reduction in total TAC during the course of lactation may needs more attention about nutritional status.

On account of the oxidative stress conditions that may appear during parturition, colostrum should provide with not only nutritional and immunological components but also antioxidative protection of newborn. There is evidence that apart from well-known antioxidative enzymes like glutathione peroxidase, superoxide dismutase, catalase or low molecular antioxidants, proteins like lactoperoxidase (LPO), lactoferrin (LF) and ceruloplasmin (CP) may exert antioxidative properties in colostrum. The aim of present study was to determine and to evaluate LPO, LF and CP activities in colostrum and milk of sows and cows. Samples were collected from 16 healthy cows five times: immediately after parturition, 12, 24 and 48 h, and 7 days postpartum as well as from 14 healthy sows five times: immediately after parturition, 6, 12, 24 and 36 h later. Examined parameters were determined spectrophotometrically at 412, 560 and 540 nm respectively. LPO activity was higher in sows as in cows and increased significantly within examined time. LF ability to inhibit superoxide radical generation was higher in sows as in cows and increased significantly within examined time. CP oxidase activity was higher in cows as in sows and decreased significantly during experimental period. In conclusion, antioxidative defence system in colostrum shows dynamic changes that allow for providing with necessary protection from oxidative stress conditions, which may appear after parturition.