Today, we are exposed to hundreds of chemicals, and not in all cases are enough tests done to prove their toxic effects. Likewise, little is known about how they can affect human hormonal systems, and even less about how they work together, mixed with each other.
This is reflected, in an article published by the Internet portal The Conversation, Barbara Demeneix, from the National Museum of Natural History of France and internationally recognized for her work in endocrinology on thyroid hormone and endocrine disruptors, also called endocrine disruptors – those chemicals that can be an obstacle to the production or activity of hormones in the human endocrine system.
All vertebrates, be they frogs or humans, need the same hormone, thyroid hormone, for their growth, which also modulates each stage in brain development . Well, for millions of years, the structure of this important hormone has remained unchanged. Increasingly, however, modern life is making it harder for it to play its crucial role, as it is highly vulnerable to chemicals, which can interfere with endocrine communication pathways between cells.
Among these endocrine disruptors we would find chemicals such as pesticides, plasticizers, flame retardants, and surfactants . As Demeneix points out in his article, we find them from the food we eat to the furniture, cleaning products, clothing and cosmetics we use. They are even found in the air we breathe and the water we drink.
Could affect IQ
And that ‘s bad news for the brain, and particularly for children’s brains . Because, according to the researcher, the thyroid hormone performs multiple functions when it comes to orchestrating the production and differentiation of the 100,000 million neurons that the human brain has; And, without the right amount of thyroid hormone at the right time, human babies would suffer severe intellectual disabilities and their IQ would be affected.
In a recent experiment with tadpoles – these have long been used to study the processes of human development – “we tested the hypothesis that common chemicals in the environment, individually and acting together, can interfere with the correct development of the brain of human beings “ , he explains.
In previous research, it had been observed that endocrine disrupted tadpoles could not transform; that is, they never became frogs. “Our article, published March 7 in Scientific Reports , shows that these young tadpoles exposed to a mix of common chemicals in concentrations commonly found in human amniotic fluid not only modified thyroid hormone signaling, but also reduced thyroid hormone signaling. total number and size of neurons and inhibited tadpole movement. ” The scientist explains that even with a limited exposure of three days, significant effects were observed on brain development in these animals.
And these kinds of findings raise a number of concerns for us. “Global chemical production has multiplied by 300 in the last 50 years, according to the United Nations Environment Program. And since all the common molecules that we use in our experiment are found in similar concentrations in the liquid human amniotic, we should be concerned about the potential effects of this mixture on fetal brain development , “warns Demeneix.
Small variations in a woman’s thyroid hormone levels early in pregnancy significantly affect her child’s IQ and brain structure, she explains. Likewise, longitudinal epidemiological studies have shown that children born to mothers with high levels of certain thyroid-altering chemicals have lower IQs. ” Children born to mothers exposed to pesticides or other chemicals can also have more neurodevelopmental problems, ” he adds.
Therefore, in her conclusions, the French researcher points to “the urgent need to review the way in which chemical products are tested before reaching the market .”
