According to the results of a UC Berkeley study published in the journal Human Reproduction, girls exposed to chemicals commonly found in toothpaste, soaps, cosmetics and other hygiene and personal care products in their prenatal years enter puberty early.
Several studies have shown that, in the last 20 years, girls and perhaps even boys have been entering puberty ever earlier. This is worrying, as the early age of onset of puberty has been linked with increased risk of breast and ovarian cancer in girls and testicular cancer in boys.
Researchers suspect that many substances in personal care products may interfere with the human endocrine system. Studies have already shown that exposure to these chemicals can alter reproductive development in rats. The substances that are considered most likely to destabilize the hormonal balance are phthalates, which are often found in perfumes, soaps, and shampoos; parabens, which are used as preservatives in cosmetics; phenols, which include triclosan, present in some kinds of toothpaste.
At UC Berkeley, they conducted research using data from the CHAMACOS (Center for the Health Assessment of Mothers and Children of Salinas) study. The CHAMACOS study recruited pregnant women who worked on farms between 1999 and 2000. While the main aim of the study was to examine the impact of pesticide exposure on child development, the researchers took the opportunity to examine the effects of other substances as well.
The team measured concentrations of phthalates, parabens, and phenols in urine samples taken from mothers during pregnancy and from children. They then followed the growth of children between 9 and 13 years of age to monitor the timing of puberty development. More than 90% of urine samples from both mothers and children showed detectable concentrations of all three classes of chemicals, with the exception of triclosan which was present in about 70% of the samples.
Scholars found that daughters of mothers who had higher levels of diethyl phthalate and triclosan in their bodies during pregnancy entered puberty at an early age. The same trend has not been observed in the boys. While waiting for the results of further research, the research team invites people to be aware that in personal care products there are substances that can disturb our hormonal balance.
Harley KG, Berger KP, Kogut K, Parra K, Lustig RH, Greenspan LC, Calafat AM, Ye X, Eskenazi B. Association of phthalates, parabens, and phenols found in personal care products with pubertal timing in girls and boys. Hum Reprod. 2018 Dec 4. doi: 10.1093/humrep/dey337.