The association of maternal food quality score (FQS) with breast milk nutrient content and antioxidant content of infant urine: a cross-sectional study

Background Breast milk (BM) is a complex fluid with a variable composition within women over time and between women in the population. The BM compositional differences are likely to be partly due to maternal dietary patterns. This study aimed to evaluate food quality score (FQS) in lactating mothers and its association with quality indicators of BM and antioxidant content of infant urine. Methods This cross-sectional study was undertaken in 350 lactating women aged 20 to 35 years. Data on dietary intake was collected using a validated food frequency questionnaire (FFQ) containing 65 food items. The FQS was calculated by integrating the scores obtained from healthy and unhealthy food groups. Subjects were categorized according to FQS adherence, with the greatest adherence being allocated to the third tertile and those with the lowest FQS in the first tertile. Antioxidant activity of the BM and infant urine samples was assessed using the Ferric reducing antioxidant power (FRAP), 2, 2′-diphenyl-1-picrylhydrazyl (DPPH), thiobarbituric acid reactive substances (TBARs), and Ellman’s assay. The total content of BM protein, calcium, and triglyceride was measured using standard biochemical kits. Results BM from mothers from the third tertile of FQS contained significantly higher DPPH, thiol, calcium, and protein levels compared to BM from those in the lowest tertile ( p ˂0.05). Infant urinary DPPH and FRAP was also significantly higher in the highest tertile vs. the lowest tertile ( p ˂0.05). Conclusion High maternal adherence to the FQS was associated with a high BM quality and antioxidant content of infant urine.