Breast milk iodine and perchlorate concentrations in lactating Boston-area women.
BACKGROUND
Breastfed infants rely on adequate maternal dietary iodine intake.


OBJECTIVE
Our objective was to measure breast milk iodine and perchlorate, an inhibitor of iodide transport into the thyroid and potentially into breast milk, in Boston-area women.


METHODS
The study included 57 lactating healthy volunteers in the Boston area.


METHODS
Breast milk iodine and perchlorate concentrations and urine iodine, perchlorate, and cotinine concentrations were measured. For comparison, iodine and perchlorate levels in infant formulae were also measured.


RESULTS
Median breast milk iodine content in 57 samples was 155 microg/liter (range, 2.7-1968 microg/liter). Median urine iodine was 114 microg/liter (range, 25-920 microg/liter). Perchlorate was detectable in all 49 breast milk samples (range, 1.3-411 microg/liter), all 56 urine samples (range, 0.37-127 microg/liter), and all 17 infant formula samples (range, 0.22-4.1 microg/liter) measured. Breast milk iodine content was significantly correlated with urinary iodine per gram creatinine and urinary cotinine but was not significantly correlated with breast milk or urinary perchlorate.


CONCLUSIONS
Perchlorate exposure was not significantly correlated with breast milk iodine concentrations. Perchlorate was detectable in infant formula but at lower levels than in breast milk. Forty-seven percent of women sampled may have been providing breast milk with insufficient iodine to meet infants' requirements.
Pearce
Elizabeth N
EN
Section of Endocrinology, Diabetes, and Nutrition, Boston Medical Center and Boston University School of Medicine, 88 East Newton Street, Evans 201, Boston, MA 02118, USA. elizabeth.pearce@bmc.org
Leung
Angela M
AM
Blount
Benjamin C
BC
Bazrafshan
Hamid R
HR
He
Xuemei
X
Pino
Sam
S
Valentin-Blasini
Liza
L
Braverman
Lewis E
LE
D000328:Adult; D001900:Boston / Q000453:epidemiology; D004032:Diet; D005260:Female; D006801:Humans; D007223:Infant; D007225:Infant Food / Q000032:analysis; D007227:Infant Nutritional Physiological Phenomena; D007231:Infant, Newborn; D007455:Iodine / Q000378:metabolism* / Q000652:urine; D007774:Lactation / Q000502:physiology; D008875:Middle Aged; D008895:Milk, Human / Q000737:chemistry*; D010472:Perchlorates / Q000378:metabolism*; D012907:Smoking / Q000378:metabolism
D010472:Perchlorates; D007455:Iodine