The paraben family of substances—including methylparaben, propylparaben, and butylparaben—are preservatives frequently found in cosmetics. Approximately 90% of products found in grocery stores contain some amounts of parabens, making it difficult for even the most careful consumer to completely steer clear of them. Those concerned are less nervous about individual items’ paraben levels, with the acceptable range being set by the Food and Drug Administration, and more worried about the potential effects of cumulative exposure.
That is, until we start discussing pregnant women, where the health of the mother and the sensitive development of the child are both of great concern.
“Bearing in mind the future health of their children, expectant mothers really should use paraben-free products during the sensitive periods of pregnancy and breastfeeding”, claims Professor Irina Lehmann, who currently teaches at the Berlin Institute of Health (BIH) as well as the Charité – Berlin University Hospital. She and her team focused on how paraben exposure during pregnancy can affect DNA methylation levels, and how that can lead to an epigenetic risk to be overweight in childhood.
Epigenetics Drive Overweight Offspring In Paraben-Exposed Pregnant Mothers
The study began with epidemiological data from expectant mothers who were using high quantities of paraben-containing cosmetics, and in whom high levels of urinary parabens were detected. Further data analysis seemed to show a link between butylparaben exposure and increased risk to be overweight in early- to mid-childhood. But how exactly was this risk borne into action?
The team used a mouse model in which an experimental group of pregnant mice were exposed to parabens. This group demonstrated higher butylparaben levels in the urine when compared to the unexposed control group of pregnant mice—a result consistent with the findings in human models. The offspring of these mice were then monitored throughout development; female offspring of the exposed mice were consistently found to have significantly higher weight as well as levels of food intake.
The team determined that the mice exposed to butylparaben exhibited increased levels of DNA methylation to the pro-opiomelanocortin (POMC) gene which is involved in controlling the experience of hunger. They then treated the mice with a DNA methyltransferase (DNMT) inhibitor called 5-Aza-2’-deoxycytidine for two weeks, to which they found that both food consumption and body weight had reduced.
Since epigenetics control gene expression without modifying the DNA sequence itself, they could potentially be reversed in individuals—and as such represent very attractive therapeutic pathways, which is part of why scientists are getting more excited to study them. “The influence of parabens during gestation obviously gives rise to epigenetic modifications in the offspring that permanently disrupt the regulation of the natural feeling of satiety [via POMC]. This means that they have a higher food intake”, said Dr. Tobias Polte, an environmental immunologist at UFZ.
More Research Needed to Clarify Modifications Involved In Humans
Further study will be needed to see if there are any further or additional epigenetic modifications at play, as well as to confirm these findings in humans—starting in childhood. It does seem likely, however, that parabens are implicated in the incidence of children being overweight if their pregnant mothers are exposed. It’s worth noting that parabens could be one risk factor, but there are several others including poor diet, insufficient exercise, and other similar unhealthy lifestyle habits. “Epigenetic modifications that relate to the regulation of satiety are only one possible end point”, says Dr. Polte. “Intergenerational effects of environmental factors have often been underestimated to date. We hope that our research will help to focus greater attention on such factors in future.”
Source: Leppert, B. et al. (2020). Maternal paraben exposure triggers childhood overweight development. Nat Commun(11)561
Reference: UFZ Helmholtz Centre for Environ. Research. “Overweight from cosmetics.” UFZ Helmholtz Centre for Environ. Research Press Resealses. 12 Feb. 2020. Web.