Habitual dietary intake and glutamic acid in durable milk at one month postpartum

Glutamic acid (Glu), an umami component in human milk, has been suggested to play an important role in the prevention of allergies and infections in infants, but the relationship between mothers' habitual diet and Glu in human milk is not clear. Therefore, we aimed to clarify the relationship between maternal dietary habits and Glu concentrations in durable milk during the first month postpartum in 41 lactating women using a cross-sectional prospective study. Metrics included habitual dietary intake at 1 month postpartum (Self-Reported Dietary History Questionnaire), Glu concentration in durable milk whey, and plasma at 1 month postpartum. There was no correlation between Glu concentration in plasma and durable milk Glu concentration at 1 month postpartum. Food items that were correlated with plasma and milk Glu concentrations were sparse in Glu or did not contain Glu; therefore, we could not determine the relationship between Glu concentrations in durable milk and maternal dietary intake. In addition, Glu concentration in durable milk was significantly higher among multipara than primipara and among mothers with a relatively high degree of physical activity. Although the study did not show that mothers' habitual dietary intake affected milk Glu, Glu concentrations in durable milk were approximately 30 times higher than those found in plasma. Further research is needed to clarify the relationship between individual factors and milk or plasma Glu.