Healthy, full-term newborns effectively metabolize BPA, remain at low risk
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Many newborns are exposed to bisphenol A, but healthy, full-term infants are able to quickly and effectively metabolize the chemical, according to research in The Journal of Pediatrics.
The results, according to researchers, challenge the belief that newborns bear a greater health risk because they have a more difficult time metabolizing bisphenol A (BPA), which is commonly found in food and drink packaging, cash register receipts and many plastics.
“There has always been an assumption that the immature liver of the newborn would lead to accumulation of BPA, much like we see with bilirubin in the jaundiced newborn,” Rebecca M. Nachman, PhD, MPH, of the department of environmental health sciences at Johns Hopkins Bloomberg School of Public Health, told Endocrine Today. “But our study shows that this is not the case in healthy, full-term newborns. It shows their livers are more efficient in handling BPA and their exposures are lower than we thought.”
Rebecca M. Nachman
Nachman and colleagues at other institutions analyzed data from 44 full-term newborns seen at Johns Hopkins Hospital between December 2012 and August 2013. Researchers collected urine samples in newborns aged 3 to 6 days and again at age 7 to 27 days to measure free BPA — BPA that is not metabolized — and BPA glucuronide (BPAG), which is the metabolized form of the chemical.
Free BPA concentrations were below the limit of quantification in all 78 urine samples collected, whereas 71% of the samples contained BPAG (77% at first visit, 64% at second visit). Urinary BPAG concentrations decreased with age, with the difference between the two age groups being statistically significant (P = .002).
“These findings demonstrate both widespread exposure to BPA and efficient glucuronidation during the neonatal period,” the researchers wrote.
Infants who were exclusively breast-fed or fed a combination of formula and breast milk had lower concentrations of BPAG compared with infants who were exclusively formula-fed, but the difference was not significant, according to researchers.
More research is needed to understand the health risks posed by very low exposures to hormonally active substances like BPA, Nachman said.
“In toxicology, we often say ‘the dose makes the poison,’ but this tenet may not be applicable in the context of endocrine-disrupting chemicals,” Nachman said. “Researchers hypothesize that [endocrine-disrupting] substances may have effects even if the exposures are very low.”
In addition, studies are needed to identify both unknown sources of BPA and the chemicals replacing BPA that may themselves be endocrine disruptors, Nachman said.
“Some alternatives that have replaced BPA in BPA-free products are endocrine-disrupting chemicals themselves,” Nachman said. “So research is needed to understand whether exposure to these alternatives is on the rise.” – by Regina Schaffer
For more information:
Rebecca M. Nachman, PhD, MPH, can be reached at the Department of Environmental Health Sciences, Johns Hopkins Bloomberg School of Public Health, 615 N. Wolfe St., Baltimore, MD 21205; email rnachman@jhu.edu.
Disclosure: The researchers report no relevant financial disclosures.