Macronutrient, immunoglobulin a and total antioxidant capacity profiles of human milk from 1 to 24 months: a cross-sectional study in Thailand

Abstract

Background An extended duration of breastfeeding of up to two years is encouraged by many health authorities, but information regarding the composition of milk after one year postpartum is limited. The goal of this study was to determine the association between the duration of lactation and macronutrient contents, immunoglobulin A (IgA) levels and total antioxidant capacity (TAC) in human milk (HM), from 1 to 24 months postpartum. Methods Cross-sectional milk samples were collected between January and April 2019 from mothers with healthy full-term children who had been lactating for 1 to 24 months. The HM was biochemically analyzed for protein and carbohydrate contents by colorimetric assays. The fat content was determined by capillary centrifugation, and the energy content was calculated from the results of centrifugation assays. IgA levels and TAC were determined by ELISA and a Trolox equivalent antioxidant capacity (TEAC) assay, respectively. Pearson’s correlation coefficient and Spearman’s rank correlation coefficient were used to determine associations between months of lactation and milk composition, and multiple regression analysis was used to assess associations between months of lactation and milk composition adjusted for relevant covariates. Differences were considered significant at p < 0.05. Results One hundred eighty-four milk samples were analyzed. The month of lactation was positively associated with the fat concentration (B = 0.31, SE = 0.09, p = 0.001), energy content (B = 3.11, SE = 0.92, p = 0.001), and IgA (B = 4.17, SE = 1.08, p < 0.001) but negatively associated with the carbohydrate concentration (B = − 0.22, SE = 0.01, p = 0.04). No association was observed between the month of lactation and the protein concentration or TAC after adjustment for maternal age, maternal BMI, birth order, and breastfeeding frequency. Conclusion The duration of lactation was found to be positively associated with the fat, energy, and IgA content in HM for up to two years postpartum, and negatively associated with carbohydrate concentration. More prospective cohort studies are needed to obtain evidence-based knowledge regarding the changes in HM composition throughout the course of lactation.

SARS-CoV-2 Antibodies in Breast Milk After Vaccination

“…13,14,42 Although our finding of higher immunoglobulin levels in HM samples where breastfeeding was prolonged for over 23 months was unexpected, a positive correlation between the length of breastfeeding (between >6 months and 2 years of age) and the immunoglobulin concentration in milk, regardless of the mother's age or BMI, had been described previously. 43,44 In addition, increased concentrations of proteins, 41,45 immunoglobulins, lactoferrin, and lysozyme have been described in lactation periods of over 18 months and during the involution of the breast near weaning. This phenomenon may be particularly beneficial when there is a need for augmented local protection against infections and may favor that sick infants can return to the breast during this period.…”

The Breast Milk Immunoglobulinome

“…In fact, values are found in studies that evaluated the two previous types of milk samples as well, but also in 16 new projects, constituting a total of 109 sets of samples. The sampling period starts in the third week of lactation [59,75,80] and lasts for 24-26 months [92][93][94]. However, the milk obtention is performed on a particular day in early mature milk, such as day 21 [59,75,80], day 28 [59,77,80], or on specific days later on, such as those studies analyzing samples from day 42 [45] or day 56 [80], among others.…”

“…Besides this, some of the studies included samples from a narrow period of days, e.g., 2-4 days [60,86,95], although most of them collected samples during a longer interval of weeks [88,96,97] or even expressed in certain months [81,88,98]. In addition, some sampling is performed during very long periods, such as for 4-6 months [48,88,92].…”

The role of exclusive breastfeeding on sIgA and lactoferrin levels in toddlers suffering from Acute Respiratory Infection: A cross-sectional study

“…Although there was a decrease, it did not show a significant relationship between sIgA and lactoferrin levels with the age of mothers and toddlers. The results of previous studies also found that IgA and lactoferrin in breast milk were not associated with maternal age, but there was a significant relationship between lactoferrin levels and infant age [ 40 , 41 ]. Meanwhile, according to parity, lactoferrin levels were higher in multiparas compared to primiparas and grandes.…”