A new study by US researchers has revealed that exposure to phthalates, man-made chemicals found in baby care products like shampoo, talc and lotion, is widespread in infants and that the chemicals are metabolised in their bodies and can be detected in their urine.

The study was carried out by researchers at the University of Washington in Seattle, the US Centers for Disease Control and Prevention (CDC) in Atlanta, and the University of Rochester School of Medicine and Dentistry in New York and is published in the February issue of the journal Pediatrics.

Recent research has suggested that phthalates can alter the development of the male reproductive system, but until this study, how the chemicals got into babies’ bodies had not been investigated very well.

The researchers tested the urine of 163 babies born between 2000 and 2005 for 9 phthalate metabolites and correlated the results with information given by their mothers on products that the infants had been exposed to in the 24 hours leading up to the urine sampling. The products included anything applied to the babies’ skin such as baby shampoos and lotions.

The analysis revealed that:

  • 81 per cent of infants had detectable levels of 7 or more phthalate metabolites in their urine.
  • Exposure to baby lotion was significantly linked to detectable levels of monoethyl phthalate and monomethyl phthalate.
  • Exposure to baby powder was significantly linked to detectable levels of monoisobutyl phthalate.
  • And exposure to baby shampoo was significantly linked to detectable levels of monomethyl phthalate.
  • The more products a baby was exposed to, the more links there were to different phthalates.
  • Most of the links were stronger in the younger babies (under 8 months).

The researchers concluded that exposure to phthalates was widespread and variable among babies:

“Exposure to lotion, powder, and shampoo were significantly associated with increased urinary concentrations of monoethyl phthalate, monomethyl phthalate, and monoisobutyl phthalate, and associations increased with the number of products used.”

They added that the association was strongest in the younger babies, who “may be more vulnerable to developmental and reproductive toxicity of phthalates given their immature metabolic system capability and increased dosage per unit body surface area.”

Speaking to Reuters Health, study co-author Dr Sheela Sathyanarayana said that scientists don’t know what long term effect phthalates might have on human health, but a large number of animal studies and a handful of human studies suggest they affect the development of the reproductive system.

Parents who want to reduce their children’s exposure to these chemicals might consider using products such as lotions, baby powder and shampoos sparingly, she said.

In the US, manufacturers are not required to show the phthalate content of personal care products on the package or label.

“Baby Care Products: Possible Sources of Infant Phthalate Exposure.”
Sheela Sathyanarayana, Catherine J. Karr, Paula Lozano, Elizabeth Brown, Antonia M. Calafat, Fan Liu, and Shanna H. Swan.
Pediatrics, Vol. 121 No. 2, February 2008, pp. e260-e268.

Click here for Abstract.

Sources: journal abstract and article, Reuter’s Health.

Researchers from Brigham and Women’s Hospital published a report in Environmental Health Perspectives which revealed that women with high phthalate levels in their urine have a considerably higher risk of developing diabetes, compared to those with the lowest levels. (Link to article)

Researchers from the Children’s Environmental Health Center at The Mount Sinai Medical Center found a link between obesity in young children and exposure to phthalates. (Link to article)

Scientists from the University of Rochester Medical Center found in a pilot study that young boys whose mothers had high phthalate urine levels when they were pregnant were less likely to “play like boys” – engage in boyish banter, play fighting, and use masculine toys. (Link to article)

A Finnish study found a link between phthalates and diabetes risk among elderly people; even when circulating phthalate levels were only moderately elevated their risk doubled. (Link to article)

At Columbia University’s Mailman School of Public Health, scientists found “prenatal exposure to phthalates may adversely affect child mental, motor and behavioral development during the preschool years”. (Link to article)

Scientists from the University of Michigan, in a large-scale study, confirmed a link between phthalate and BPA concentrations and thyroid hormone levels. Thyroid hormones play a key role in reproduction, metabolism, energy balance and other body functions. (Link to article)

Written by: Catharine Paddock, PhD