Oxidative status in colostrum and mature breast milk related to gestational age and fetal growth

Abstract

Introduction

The effect of gestational age and fetal growth on the oxidant/antioxidant status of breast milk is poorly understood.

Objective

To evaluate the oxidative stress biomarkers in colostrum and mature milk according to gestational age and fetal growth.

Method

A longitudinal study with mothers of premature and term infants, born in a tertiary referral hospital between 2014–2018. Inclusion criteria: postpartum women with a singleton pregnancy, who intended to exclusively breastfeed. Exclusion criteria: maternal diabetes, use of medication, drug addiction, congenital infection or malformation, mastitis, and failure to collect colostrum. Four groups were formed according to gestational age and birth weight (appropriate and small): Preterm small (n = 37), Preterm appropriate (n = 99), Full-term small (n = 65), and Full-term appropriate (control, n = 69). The colostrum samples were collected between 24-72 h and the mature milk was sampled in the 4th week of lactation for malondialdehyde (biomarker for lipid peroxidation) and Glutathione peroxidase, Catalase, and Superoxide dismutase measurements. The data were compared among groups using the Chi-square test or Fisher’s exact test, one-way analysis of variance followed by Wald’s Distribution test and repeated measures analysis of variance.

Results

We found a lower malondialdehyde level in colostrum in preterm groups and term small for gestational age, and the antioxidant enzymes Superoxide dismutase and Catalase activities were higher for preterm compared to term groups. The malondialdehyde levels differed in mature milk samples (Full-term small > Full-term appropriate > Preterm small > Preterm appropriate). The malondialdehyde levels increased during lactation in all groups except Preterm appropriate, and the levels of Catalase decreased in preterm groups.

Conclusion

The oxidative status in breast milk is influenced by gestational age and fetal growth, which increased antioxidant defense for preterm infants and decreased oxidative stimuli for small for gestational age infants. These findings contribute to encouraging breastfeeding for newborns.

Keywords:

• Breast milk
• premature infant
• intrauterine growth restriction
• oxidants
• antioxidants

Authors’ contribution

Luiza Tavares Carneiro Santiago designed the study, carried out the experiments, analyzed the data and drafted the manuscript.

Natália Alves de Freitas collected the samples and carried out the experiments.

José Donizeti de Meira Junior collected the samples

José Eduardo Corrente performed the statistical analysis

Verônyca Gonçalves Paula revised the manuscript

Debora Cristina Damasceno contributed to the study methodology

Ligia Maria Suppo de Souza Rugolo conceived and designed the study, analyzed the data and drafted the manuscript.

All authors read and approved the final manuscript.

Disclosure statement

The authors declare no conflicts of interest.

Additional information

Funding

The study received financial support from Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) – Brazil (grant number: 2014/12784-9).