“Spanish children urinate plastic,” says doctor and researcher Nicolás Olea provocatively. He doesn’t exaggerate. Nor is he wrong when he warns of the presence of perfluorinated chemicals, very persistent chemicals, in the blood of the entire country or in breast milk. Olea forcefully illustrates the extensive exposure that humans have to the so-called endocrine disruptors, compounds capable of emulating the body’s natural hormones and affecting health. These chemicals, invisible to the human eye, but present in the environment and in everyday products, can interfere with the endocrine system before birth and influence reproductive health and the development of various diseases, such as cancer, diabetes, obesity or attention deficit hyperactivity disorder, among others. An investigation Recent research suggests, for example, that early exposure to some disruptors can cause an earlier onset of puberty.
Human exposure to these chemicals worries the scientific community. To begin with, because they are everywhere: in cosmetics, in personal hygiene products, in food packaging… And it is difficult to completely escape them. “Research is very abundant in two aspects: in the mechanisms of how these pollutants interfere with hormonal receptors; and in human exposure to these compounds. The evidence there is is more than enough to intervene preventively,” warns Olea, who is a professor at the University of Granada and a doctor at the Clinical Hospital of the same city. Pesticides, heavy metals, bisphenol-A or parabens are some of the most well-known and studied disruptors.
If natural hormones are like a kind of messengers—substances that travel through the blood and put an emitter in contact with a receiver, like the ovary with the breast, for example—what endocrine disruptors do is alter the entire network. of communication and imitate the role of natural molecules responsible for signaling and dialogue between cells and organs. These chemicals are capable of interfering with any part of this communication process, whether by altering the transport of hormones, blocking receptors or distorting the growth of cells that produce hormones, for example. “They can intervene in synthesis, transport or binding to the receptor and lower or increase hormonal activity. Although the most common thing is to interfere with the receiver, they are like hackers of that message [que llevan las hormonas]“, agrees Olea.
There are more than 2,000 chemicals identified with the ability to interfere with endocrine processes and alter health. But, probably, says the researcher from the University of Granada, these are only “the tip of the iceberg.” “The hormonal systems that have been studied are limited (estrogenic, androgenic, thyroid…). We suspect there are endocrine disruptors related to vitamin D, which is actually a hormone. But we do not know who are those who compete and interfere in that system,” reflects Olea, who is also a member of the ALIMENTTA thinktank and collaborator in the Rezero campaign, A future without toxins.
“We live in a chemical soup and we don’t have much idea what happens if you are exposed to many different endocrine disruptors.”
Martine Vrijheid, director of the Environment and Lifelong Health Program at ISGlobal
Martine Vrijheiddirector of the Environment and Lifelong Health Program at ISGlobal, highlights, however, some good news in the midst of this scenario that is so unflattering for human health: “In general, the concentration of these chemical substances that “We found in blood samples seem very low, although we need better information about the health effects of even low-level exposure.”
Among the endocrine disruptors that cause the most concern are polybrominated compounds, which are flame retardants and are found in numerous synthetic and textile products. “They are generally from exposure inside the home and are related to thyroid problems,” explains Olea. Other chemicals in the spotlight are phthalates and phenols, which are also linked to infertility in adults and stunted growth and ADHD in children.
Scientists are also concerned about perfluorinated compounds (known as PFAS), which repel water and oil and resist extreme temperatures. They are worrying, says Vrijheid, because “not only are they endocrine disruptors, but they are the so-called forever chemicals: They are very persistent in the environment and in the body.” These chemicals can affect the immune system, generate liver toxicity or cause damage to the reproductive healthlike infertility. They have also been related to diabetes and obesity and an impact on the brain has been described, with effects on neurodevelopment, lists the ISGlobal researcher.
Windows of vulnerability
Experts admit that it is complex to measure the impact of each chemical because the dose-response relationship is not linear: there is not always a proportional relationship between the exposure dose and the magnitude of the effect. Furthermore, remembers Olea, “there is a background within the body” and, although exposure to endocrine disruptors can also occur at any time in life, there are windows of special vulnerability.
The prenatal stage, when the fetus is in the process of formation, is one of those periods of susceptibility: these chemicals can cross the maternal placenta and interfere with the child’s long-term health. An investigation published in the journal Jama Pediatrics In 2018, it found, for example, that prenatal exposure to various types of phthalates was associated with a delay in language in minors.
The prepubertal stage is also another window of special susceptibility because it is the time when the body prepares to begin hormonal activity. In fact, a paradigmatic phenomenon associated, in part, with exposure to endocrine disruptors is the increasingly earlier onset of puberty. Research recently published in the journal Endrocrinology, argues, for example, that ambrette musk, which is a common fragrance component of soaps, detergents and creams, and other synthetic nitromusks “could be contributing to the trend of earlier puberty.” “Although our in vitro and in vivo data do not provide direct evidence supporting an effect on puberty, they represent a first step toward linking musk ambrette to neuroreproductive axis activity during development. This possibility deserves further study,” the authors state.
The scientific results are limited, but it is not the first time that a similar hypothesis has been raised. Anders Juul, a pediatric endocrinologist and clinical professor at the University of Copenhagen, said, speaking to The Lancetthat exposure to endocrine disruptors, along with increased fat mass, may be driving the “worrying trend toward earlier puberty.” “Environmental chemicals with hormone-like activities may promote premature activation of the pituitary-gonadal hormonal axis, leading to pubertal development, and/or act directly to stimulate the mammary gland with estrogenic or antiandrogenic activity,” he said. In a recent meta-analysis, however, Juuls failed to demonstrate a clear association between pubertal age and exposure to any individual chemical.
Chemical combination
More research is needed, admit all the voices consulted, to refine the impact of these disruptors. And it is also necessary, Vrijheid emphasizes, to delve into the effects of the combination of these chemicals. “There are many studies on endocrine disruptors, but most of them focus on one chemical or perhaps a few from the same group. There are very few studies looking at what happens if you have low exposure to many of these chemicals. “We live in this chemical soup and we don’t have much idea what happens if you are exposed to many different endocrine disruptors.” a study published last May suggested that exposure to a mixture of this type of hormone disruptors is associated with poor metabolic health and contributes to the increase in metabolic syndrome (obesity, diabetes, hypertension…) throughout life.
Experts also regret the lack of information and clear guidelines for citizens. “Maybe we could give better advice on what products they could avoid to reduce exposure. But this is difficult because we don’t have good information on which chemicals are used in which products. We need better labeling,” defends Vrijheid. Individual measures can be taken, such as reducing the intake of processed or canned products, ventilating and cleaning the interiors well from dust or not heating food in plastic lunch boxes in the microwave; but a scientific review last year concluded that “policies that reduce or eliminate endocrine disruptors in manufacturing and processing across multiple sectors, rather than individual behavior change, may have the greatest impact on population exposure.”
The speed of the industry, however, does not help control the rise of new disruptors either. ”When a chemical product is banned, it is replaced by 10 new ones, and it is very difficult to keep track of that,” laments the researcher. The industry moves faster than science and regulators are the slowest actor of all, adds Olea. And he gives an example: “In 1995 we published for the first time that bisphenol A was in the coating of canned food. And until 2011 he did not retire from bottles. And until December 31, 2024, it will not be banned from the EU. It takes a long time to make decisions.”
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