Iodine in Human Milk: A Systematic Review.

Area of Science:

• Nutrition Science
• Pediatric Health
• Endocrinology

Background:

• Infants rely on human milk for iodine, essential for physical and neurological development.
• Optimal breast milk iodine concentrations for infant equilibrium are not well-established.
• Mammary glands concentrate iodide, but variability exists in breast milk iodine levels.

Purpose of the Study:

• To review trends in breast milk iodine concentrations during lactation.
• To identify maternal factors and interventions affecting breast milk iodine.
• To assess the relationship between breast milk iodine and infant status, informing optimal concentration recommendations.

Main Methods:

• Systematic literature search using MEDLINE/PubMed.
• Inclusion of original observational and intervention studies within the first 12 months of lactation.
• Analysis of studies measuring iodine concentration in human milk.

Main Results:

• Breast milk iodine concentrations are highest in colostrum and decline throughout lactation, varying significantly by population.
• High-dose or daily iodine supplementation during lactation effectively increased breast milk iodine levels.
• No inverse correlation was found between breast milk iodine and perchlorate concentrations in the reviewed studies.

Conclusions:

• Breast milk iodine concentrations decrease over lactation, necessitating attention to maternal intake.
• Iodine supplementation during lactation is effective in raising breast milk iodine levels.
• A breast milk iodine concentration of 150 μg/L in the first 6 months is suggested to ensure infant iodine sufficiency and prevent deficiency.