Exposure of fetuses and babies to various chemicals and toxins may change their health trajectory in the future, and in fact determine what their lives will look like
By Maya Falah, Angle, Science and Environment News Agency
If you had to think about the phase in which you were in the safest and most protected place in your life, most of you would probably choose the phase in which you were going through - then the womb kept and protected you from all the harms of the big and scary world. indeed? The triennial report of The Health and Environment Fund for the year 2017, which presents the broad picture of the state of health and the environment in Israel in 2017 and which was presented at a special conference of the foundation in the nation's buildings on December 18, this year devotes a special chapter to the populations most sensitive to exposure to environmental factors. One of the most sensitive populations, the report reveals, are pregnant women and the fetuses they bear. It turns out that while we are in the womb, we are exposed to substances that may endanger our health in the near and long term.
According to Prof. Joe Brown - an epidemiology researcher from Brown University in the USA who took part in a special seminar of the Israel Health and Environment Foundation - in recent years more and more evidence is accumulating from studies that the mother's exposure to various chemicals during pregnancy not only may cause various problems and diseases in the fetus , but may actually change and redefine his entire future health "trajectory" as a child and even accompany him as an adult.
"Nowadays it is known that the placenta does not constitute a barrier to the passage of chemical substances between the mother and the baby. This fact allows environmental factors to which the mother is exposed to pass through her to different organs in the body of the fetus," says Brown. "In other words, the fetus is actually exposed to the same substances to which the mother is exposed. In babies and young children, the exposure to various substances is even more significant than in adults - because children are not 'little adults', but are still developing and therefore much more sensitive to the effects of the physical environment. Their toxin filtering system, for example, is much less efficient than that of adults.'
Therefore, when a fetus is exposed to various chemicals and toxins, its coping with them is less effective than that of an adult person; But worse than that - the new studies indicate that the future state of health of the individual is determined to some extent already in the early stages of life, and therefore these exposures may, in fact, affect the course of his adult life as well. That is, if our healthy fetus is exposed in the womb to various pollutants, it is possible that in the advanced stages of his life he will fall ill or suffer from a problematic health condition as a result of that early exposure.
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in ongoing research called HOME Study, which was held in Ohio in the USA for over a decade and where Prof. Brown was a partner, the researchers followed pregnant women and later the fetuses they gave birth to, with the aim of testing the effect of various environmental exposures in the early stages of life (that is, starting from the fetal stage) on the future health of the child. The children born as part of the study are now more than ten years old, and the researchers have returned and examined them over the years to check how exposure to various substances in the early stages of their lives - such as lead, mercury and various pollutants - affected their health and development later on.
As part of the study, the researchers collected blood and urine tests from the mothers and the children over the years, performed chemical tests to detect chemicals in the hair and also put them through various stages of tests to measure their development and behavior.
Two articles that Brown recently published following the results of the research, demonstrate how exposures to different substances can affect the child later in life. In one of them Brown and other researchers examined how exposure of the fetus to polybrominated diphenyl ethers (PBDE) substances affects. This is a family of materials that are used in industry as flame retardants and that have been found for quite a few years in many products that we use: from everyday items that can be found in every home, such as TV screens, furniture, mattresses and various textile products, to building materials and even airplanes. To test the level of exposure of the fetus to the substances, the researchers analyzed blood samples taken from the mother at week 16 and week 26 of pregnancy, in which they tested the concentration of the substance PBDE-47 (the most common type used in industry). The researchers then followed the children born to these mothers when they were one to eight years old, to assess the effect of these exposures on their neurological development and neurobehavior.
"The brain of fetuses and babies is constantly developing, so it has very high plasticity (flexibility) compared to the brain of an adult," explains Brown. 'As such, it is much more sensitive to environmental exposures to various substances. It is still unclear to what extent this plasticity allows external factors to make changes in the brain during these stages of life, and whether they are reversible. In the case of PBDEs, previous studies have already linked these substances to lower IQ, behavioral problems and lower performance. But it is not clear how long-lasting the effect is after exposure and whether it is reversible, and this is one of the things we wanted to check through a study that lasted for years.'
Indeed, the researchers also found in this sample that there is a relationship between the level of exposure of the fetus to PBDE-47 and its neurological development later in life. The results of the study, which were based on standardized developmental and behavioral tests for children of these ages, showed that as those children were exposed as fetuses to higher concentrations of PBDE-47, they tended to show more extroverted behavior between the ages of two and eight (referring, for example, to coping with frustrations through disruptive behavior that is aimed towards the external environment - instead of their internalization). They also showed low mental and motor development at the ages of one to three, as well as lower cognitive ability at the ages of five to eight - this compared to children whose levels of exposure to the substance were less.
fattening, not lowering
Another article of Brown and co-investigators was also based on the HOME study group and examined the effect of hormone disruptors (EDCs) in the early stages of life on obesity in children up to the age of eight. In this case, the substances that the researchers tested were perfluoroalkyl substances (PFAS) - substances that are also found in products that we are all exposed to, because they are found in quite a few industrial products: various textile products such as carpets, leather products, cardboard, food packaging, cosmetic products and more. The children from HOME were all born in Cincinnati, Ohio, near a river upstream of which there is a plant that produces PFAS.
Substances that disrupt hormonal activity are also associated with obesity due to the interference with normal hormonal activity, so the researchers checked whether in this case too the exposure of the mother already during pregnancy to these substances could affect the future health of the child, in this case - his tendency to develop excess weight. Indeed, the findings revealed that there is a relationship between exposure to activity disruptors during the fetal stage and a tendency to obesity already in childhood. The study revealed that the more the children were exposed in their initial stages of life to higher levels of the substances that disrupt activity, the more they tended to have an accelerated increase in BMI (body mass index) between the ages of two and eight. In addition, they had larger adipose tissue relative to other children around the age of eight.
The researchers, by the way, are still following the children. The next round of tests will be conducted when they reach the age of 12.
Everything comes back to us
More and more studies in recent years link our health status with what we went through in childhood and even in the fetal stage, and show that genetics is not everything in life. Studies They found in the past, for example, that exposure to air pollution at different stages of pregnancy is indeed associated with a relatively low birth weight, but on the other hand, it also causes the newborn to suffer from obesity at later ages. also Exposure to mercury During pregnancy it was found to affect the IQ of the fetus. In fact, the study of epigenetics shows that sometimes exposure or changes that the mother undergoes, even before she became pregnant, may affect the health of her future offspring.
This means that many of the substances we release into the environment - including various types of chemicals and pollutants - may return to us in unexpected ways and affect the next generation as well, causing them various health problems.
"More than 80 different chemicals are produced in the world, with thousands of them produced in masses of more than half a million kilograms per year," says Brown. "Only a few of them go through any tests before going on the market. Some of these substances may pose a danger to the health of fetuses and babies, and more than that - change their entire future health trajectory, and determine which health problems they will suffer from later in their lives.'
So what, however, can be done to reduce these many harmful exposures and try to reduce the damage they cause to our health? According to the Health and Environment Fund, the responsibility for this issue rests with the state.
"We need to think about the chemicals that are constantly in our environment, in consumer products for example, just like we think about air pollution," says Dr. Ruth Estrin, the director of the foundation. "We don't expect private individuals to check what pollutants are in the air - and based on that to decide, for example, whether to move. We expect the state to monitor the air, and make sure we have clean air. Just as the protection of the population from exposure to air pollution is the responsibility of the state - so should the issue of exposure of the public to various chemicals and toxins."
"During this period, the Health and Environment Fund is helping to upgrade the existing biological monitoring capabilities in Israel and expand the required knowledge," Estrin adds. "We are currently monitoring six birth cohorts, which will help us check which substances we are exposed to in Israel and understand what happens as a result of this during the fetal period. This will help us to be much smarter about the specific exposures to focus on in Israel, and thus we can deal with them specifically - by regulating and banning the use of chemicals and relevant substances or informing the public how to avoid them. We hope that the project will help and advance us in the effort to protect the public.'
The Ministry of Health responded:
The Ministry of Health monitors the scientific and regulatory development regarding PBDEs and PFASs and works to reduce the public's exposure to them from a variety of exposure sources.
The PBDE compounds have been used for several decades for the purpose of purchasing flame retardant properties in various consumer products. While some of the compounds belonging to this chemical group were banned for use in the Stockholm Convention, there is currently no blanket ban on the use of other compounds from this group in the developed countries, including the USA and the European Union.
For several years, the Ministry of Health has been leading a move to reduce the use of flame retardants, including flame retardants from the PBDE group, in various consumer products. The ministry led to the cancellation of the obligation to use flame retardants in adult mattresses and these days a similar move is expected to be completed in baby mattresses. Also, the Ministry of Health initiated the cancellation of the obligation to add flame retardants to furniture and other household equipment, such as carpets and electronic products for home use.
The results of a study conducted in collaboration with the Ministry of Health, the University of Haifa and the Standards Institute and funded by the Health and Environment Fund are expected to be published these days. In the said study, various pollutants were tested, including flame retardants based on bromine and phosphorus, in products intended for babies and children (mattresses, changing pads, highchairs, etc.). The tested flame retardants were not found in all the products sampled.
PFAS compounds are synthetic compounds that have been used for several decades in the industry for the technological need of resistance to adhesion, resistance to wetting and resistance to staining. With the exception of a number of compounds from this group that are prohibited from being manufactured or traded in accordance with the Stockholm Convention, there is no blanket ban on their use in consumer products in developed countries. In recent years, this chemical group has been defined as an 'emerging pollutant' and today the issue is receiving more attention among the developed countries, including the USA and the European Union. The health effects attributed to PFASs are based on very high exposure of laboratory animals to these substances, in humans the scientific information is still limited.
Food and food packaging have been suggested as a possible source of exposure to the PFOS and PFOA compounds that are included in the PFAS group. However, biological monitoring surveys conducted in the US and Europe indicated very low levels of these chemicals in the human body. For example, in a recent survey conducted by the European Food Safety Authority (EFSA) it was found that the average adult consumer is exposed to PFOS and PFOA from food sources at a rate of about 3.5% and about 0.3%, respectively, in relation to the tolerable daily level of consumption for a lifetime that is not is a health concern. In accordance with this comprehensive risk assessment, the European Food Safety Authority determined that it is "highly unlikely" that exposure to these compounds from food could cause a negative health effect in humans.
