What is plasticizers and what they eat
Recently, she began to notice that some progressive young parents give water to children only in glass bottles, and seeing plastic bottles twist their faces and say that they are filled with plasticizers that poison us and disrupt hormonal levels. This observation gave me a reason to understand the issue of plasticizers and food polymers in more detail.
I will begin with the fact that different food plastics have different elasticity. If the theory is very simplified, then the elasticity of the polymer depends on the interactions between the macromolecules of which it is composed. For example, in polyethylene the interactions between the chains are weak, so some macromolecules can move freely along the others, giving the material elasticity. And if you take, for example, PVC, the interactions between macromolecules are much stronger, which makes them less mobile, and the material less elastic.
The role of plasticizers is to reduce intermolecular interactions and make polymer chains more mobile. They work as follows: depending on the type of polymer, plasticizer molecules are inserted between the polymer chains and allow them to move more freely. Since plasticizers are not chemically bound to the polymer, they can freely transfer from the food container to food.
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If we talk about plasticizers that are used in food plastics, then two names immediately come to mind: “Phthalates” and “Bisphenol A”. It is these substances that most often appear in toxicology and endocrinology articles. By the way, most plastic bottles made of polyethylene terephthalate do not contain plasticizers, since this polymer itself is elastic.
So what does modern science say about the effects of plasticizers on our bodies?
Here, as always, everything is ambiguous ...
I'll start with phthalates. Phthalates are used to make PVC elastic, and this is packaging film, conveyor belts, tubes, and other components of industrial food production. And more recently, scientists have suspected that phthalates cause endocrine disruption, as they interact with hormone receptors.
The first question I have is: is, in fact, how much phthalates released from PVC for food, and are the concentrations of phthalates that we consume correlate with the concentration of hormones in the body?
Studies have shown that the average amount of phthalates ingested with food is about 5 to 40 micrograms per kg of body weight per day. And if we consider that the phthalates' molar activity is about 100 thousand times lower than, for example, in estradiol, by simple mathematical calculations we get the following number of pharmacologically active phthalates: 0.05-0.4 nanograms per kg of weight. At the same time, the concentration of estradiol in the body of a man is about 10-40 nanograms per kg of weight, which is about a hundred times higher, and phthalates in the body do not accumulate. That is, at first glance, phthalates have almost no effect on the hormones.
But there is one catch, causing a battle in the scientific community. In most cases, the molar activity of phthalates is calculated on the basis of measuring the amount of a substance that is attached to the receptor of a certain hormone. But the work of the endocrine system includes not only the attachment of molecules to receptors, but also the synthesis of hormones and their processing, not to mention the fact that the same molecule can interact with several systems at the same time, which, naturally, no one investigated . In the database , where all known publications on phthalates activity are collected, it is shown that these substances can interact with 249 proteins and genes ... That is, it will be very difficult to prove anything concrete. In general, everything is very vague and difficult to prove.
Approximately the same story with bisphenol A, which is used, in particular, in children's bottles made of polycarbonate. I can't help but tell a funny story: for some time they write “Does not contain bisphenol A” on baby bottles, but few know that instead of bisphenol A, add bisphenol C, which differs little from bisphenol A.
What is the conclusion of this post? I do not even know, the only information that is known for sure is that modern science is not able to prove the harmfulness of plasticizers ...
I will begin with the fact that different food plastics have different elasticity. If the theory is very simplified, then the elasticity of the polymer depends on the interactions between the macromolecules of which it is composed. For example, in polyethylene the interactions between the chains are weak, so some macromolecules can move freely along the others, giving the material elasticity. And if you take, for example, PVC, the interactions between macromolecules are much stronger, which makes them less mobile, and the material less elastic.
The role of plasticizers is to reduce intermolecular interactions and make polymer chains more mobile. They work as follows: depending on the type of polymer, plasticizer molecules are inserted between the polymer chains and allow them to move more freely. Since plasticizers are not chemically bound to the polymer, they can freely transfer from the food container to food.
')
If we talk about plasticizers that are used in food plastics, then two names immediately come to mind: “Phthalates” and “Bisphenol A”. It is these substances that most often appear in toxicology and endocrinology articles. By the way, most plastic bottles made of polyethylene terephthalate do not contain plasticizers, since this polymer itself is elastic.
So what does modern science say about the effects of plasticizers on our bodies?
Here, as always, everything is ambiguous ...
I'll start with phthalates. Phthalates are used to make PVC elastic, and this is packaging film, conveyor belts, tubes, and other components of industrial food production. And more recently, scientists have suspected that phthalates cause endocrine disruption, as they interact with hormone receptors.
The first question I have is: is, in fact, how much phthalates released from PVC for food, and are the concentrations of phthalates that we consume correlate with the concentration of hormones in the body?
Studies have shown that the average amount of phthalates ingested with food is about 5 to 40 micrograms per kg of body weight per day. And if we consider that the phthalates' molar activity is about 100 thousand times lower than, for example, in estradiol, by simple mathematical calculations we get the following number of pharmacologically active phthalates: 0.05-0.4 nanograms per kg of weight. At the same time, the concentration of estradiol in the body of a man is about 10-40 nanograms per kg of weight, which is about a hundred times higher, and phthalates in the body do not accumulate. That is, at first glance, phthalates have almost no effect on the hormones.
But there is one catch, causing a battle in the scientific community. In most cases, the molar activity of phthalates is calculated on the basis of measuring the amount of a substance that is attached to the receptor of a certain hormone. But the work of the endocrine system includes not only the attachment of molecules to receptors, but also the synthesis of hormones and their processing, not to mention the fact that the same molecule can interact with several systems at the same time, which, naturally, no one investigated . In the database , where all known publications on phthalates activity are collected, it is shown that these substances can interact with 249 proteins and genes ... That is, it will be very difficult to prove anything concrete. In general, everything is very vague and difficult to prove.
Approximately the same story with bisphenol A, which is used, in particular, in children's bottles made of polycarbonate. I can't help but tell a funny story: for some time they write “Does not contain bisphenol A” on baby bottles, but few know that instead of bisphenol A, add bisphenol C, which differs little from bisphenol A.
What is the conclusion of this post? I do not even know, the only information that is known for sure is that modern science is not able to prove the harmfulness of plasticizers ...
Source: https://habr.com/ru/post/397695/
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