497 - Selenium Concentrations In Expressed Human Milk: A Systematic Review And Meta-Analysis

Poster Number: 497
Publication Number: 497.2009

Background: Selenium (Se) is an essential nutrient and component of selenoenzymes and is important in protection against oxidative tissue damage. Preterm infants are prone to oxidative injury (e.g Brochopulmonary dysplasia (BPD), Retinopathy of prematurity, cerebral white matter disease). Low Se status has been documented in preterm infants and was found to be associated with BPD. Plasma Se concentrations have been found to decrease during the first weeks of life.

Objective: To systematically review articles that reported selenium (Se) concentrations in expressed human milk at various periods of lactation.

Design/Methods: We followed the PRISMA guidelines and searched MEDLINE and Embase for relevant articles. We performed searches using the terms “milk, human and Selenium”. All clinical trials and systematic reviews were included for full-text article review. Search was restricted to English language, and we did not consider any time limitation.

Results: Figure 1 depicts the PRISMA flow diagram of the literature search. Table 1 depicts the meta-analytic results (weighted averages with pooled standard deviations and sample size) of Se concentrations in HM at the different periods of lactation examined. Importantly, not all studies analyzed Se HM concentrations at all the periods of lactation that we defined. Therefore, number of studies differs from period to period and is not identical to 49. Selenium concentrations decreased massively from Colostrum values from an average of 32.3 µg/L to first trimester of lactation with an average of 8.3 µg/L (P < 0.001). They then increased progressively (and significantly, P< 0.005) over time until after the first year of lactation, reaching average values of 18.7 µg/L.

Conclusion(s): Our study provides valuable data related to pooled analysis, extracted from 49 studies of Se concentrations in EHM. Its results could be used for estimates of Se intake in human milk fed infants during and shortly after the first year of life. From our results we may calculate that an exclusively breast fed, 3 months old infant, weighing an average of 6.4 kg and taking an average of 700 cc of milk per day, is expected to have an average Selenium intake of 8.3 X0.7=5.81 µg, or 0.9 µg/kg body weight. This number is much lower than previous estimates of Se intake in breast-fed infants of 2.3 mcg/kg per day. It is likely that current recommendations of Se intake are excessive, but are not likely to lead to toxicity.