The most widely used pesticides in the world may disrupt our hormones and adversely affect human health, a study has found.
Neonicotinoids frequently make headlines because of their harmful effects on honeybees and other insect pollinators.
Neonicotinoids act on insects' nervous systems, killing them by paralysis. Very little research has been done on their effects on human health.
The study, published in the journal Environmental Health Perspectives, shows that they may also have an impact on human health by disrupting our hormonal systems.
"Endocrine disrupters are natural or synthetic molecules that can alter hormone function. They affect the synthesis, action, or elimination of natural hormones, which can lead to a wide variety of health effects," said Elyse Caron-Beaudoin from National Institute of Scientific Research (INRS) in Canada.
Researchers developed methods to test the effect of neonicotinoids on the production of estrogens, essential hormones with several biological functions.
By targeting aromatase, a key enzyme in the synthesis of estrogens, they were able to test the impact of three neonicotinoids on breast cancer cells in culture after exposure to concentrations similar to those found in the environment in agricultural areas.
The results show an increase in aromatase expression and a unique change in the pattern in which aromatase was expressed, which is similar to that observed in the development of certain breast cancers.
"However, as these results were obtained in a cellular model of breast cancer, we cannot necessarily conclude that exposure to pesticides at concentrations similar to those in the human environment would cause or promote cancer," INRS professor Thomas Sanderson.
This study is the first evidence that neonicotinoids have an effect on aromatase gene expression and may potentially alter estrogen production.
Hormonal disturbance by these pesticides will need to be confirmed in future studies, but the results obtained by the INRS team indicate that it caution should be exercised in the management and use of neonicotinoid insecticides.