Comparative Assessment of Markers of Oxidative Stress in Human-milk and Plasma of Lactating Mothers

Abstract

Background: Human-milk is a complex extracellular fluid with different biochemical composition compared with blood. The present study assessed the levels of markers of oxidative stress in human-milk and plasma of healthy lactating mothers.

Methods: Forty lactating mothers (22-36 years) volunteered to participate in this study. They were non-smokers and apparently normal nursing mothers who had normal delivery without postnatal complications. Blood and breast-milk samples were collected from the lactating mothers between 6th and 18th weeks after delivery. Total antioxidant potential (TAP), total plasma peroxides (TPP) and malondialdehyde (MDA) were determined in both human-milk and blood of the mothers using spectrophotometric methods. Oxidative stress index (OSI) was determined as the percent ratio of the TPP and TAP.

Results: The results showed that TAP, TPP and OSI increased significantly (p<0.001) in human-milk compared with the plasma. The plasma / human-milk ratios of TAP, TPP and OSI were 1:3, 1:5 and 1:2 respectively. The level of MDA was significantly (p=0.01) lower in the breast-milk, compared with the plasma. In the plasma, levels of OSI correlated significantly with TAP (r= -0.46; p= 0.015) and TPP (r=0.90; p <0.001) while in the breast-milk, OSI correlated significantly with only the TAP (r = -0.76; p<0.001).

Conclusion: It could be concluded that the higher TPP in the human milk would be beneficial against pathogens, while the bio-accumulated antioxidant molecules regulate free radical load to avert the consequences of oxidative stress in the breast tissue.