The effect of softening agents on the body

Plastic in your food

Children reach puberty sooner when their mothers had been exposed to PCBs. Sietske Berghuis finds this worrying. Almost all women have this chemical compound in their system.
By Christien Boomsma / Translation by Sarah van Steenderen / Photo by Teresa Morris 

No, Berghuis says, she probably won’t buy plastic bottles for her children anymore. Better to get glass ones.

After all, you have to put bottles in the microwave to heat up their contents. And plastic contains softening agents that release at high temperatures. These agents can end up in the milk – and in your child’s body. Who knows what harm that might cause? ‘I have become warier’, says Sietske Berghuis, PhD candidate at the Faculty of Medical Sciences. ‘After all, who knows what those compounds do in our bodies?’

The compounds could affect the endocrine system, young developing brains, even the locomotor system. And you don’t just pass the chemical agents to your child; your daughter could also pass them to her children.

Nobody wants that, Berghuis knows: over the past few years, she has investigated the influence of PCBs on the neurological and hormonal development of children and teenagers. She is receiving her doctoral degree on 30 April. PCBs have been banned since 1985 and the mothers in her study did not get pregnant until 2000 – but today’s teenagers still suffer consequences from PCBs. And that is cause for concern.

Lower IQ

‘Prior to 1985, they were used in everything’, says Berghuis. ‘They were used as softening agents in plastic, in refrigerants, in insulation material, as flame retardants – even in ink. The problem is that these compounds are sturdy; they can’t be broken down easily.’

PCBs are stored in animal fat, and eventually end up in the food chain: human beings consume this animal fat through meat, fish, and milk. A study of the blood serum of two groups of women in the northern Netherlands who all got pregnant around the year 2000 showed that these compounds are still present in their bodies, and are passed to their children via the placenta and breastmilk.

Over the past few years, we’ve seen an increase in children reaching puberty earlier

People have known for a long time that large amounts of the compounds are harmful. A leak in a cooling system in Japan in 1968, for example, contaminated large amounts or rice oil. This contamination led to children who had a lower IQ, a lower birth weight, edema, and liver damage, to name just a few. But Berghuis wanted to know if trace amounts had consequences as well. She wanted to study the children who suffered from what she called ‘background exposure’. ‘Over the past few years, we’ve seen an increase in children reaching puberty earlier’, she says. ‘We also know that PCBs can influence the endocrine system. So PCBs could be an explanation for this phenomenon, even after all this time.’

Old-fashioned VHS

Berghuis started studying short videos of three-month-old babies whose mothers had participated in the research in 2000. She went through dozens of old-fashioned VHS tapes, assigning a score to how the babies moved. ‘Normal movement is fidgety’, she says. ‘The babies kick their feet, wave their arms around. I watch how smoothly they move.’

The degree of smoothness in the babies’ movement was clearly connected to the amount of PCBs in their mothers’ blood serum. The development of their motor skills was still within ‘normal’ levels, but the children who had been exposed to larger amounts of PCB scored markedly lower on the scale.

The babies’ neurological development was also affected by the chemical compounds. Interestingly enough, however, the effect was actually positive: the children had better reflexes and were better at following objects with their eyes, among other things.

Voice change

But that is not cause for celebration, says Berghuis. An improved neurological development is not necessarily a good thing. ‘The human body has to react to this. It might try to overcompensate, and we have no idea whether that’s a good thing.’

The girls developed pubic hair and breasts at an earlier stage, and the boys had larger testicles and their voices changed earlier

The results of her study led her to approach the mothers and their children for a follow-up. The babies had all reached puberty by now, and Berghuis wanted see if the effects had persisted. And she again found clear effects, although the children’s motor skills had improved. It turned out that both the boys and the girls had reached puberty at an earlier age because of the PCBs. The girls developed pubic hair and breasts at an earlier stage, and the boys had larger testicles and their voices changed earlier.

Is this a bad thing? Berghuis suggests it might be. Accelerated puberty can increase a person’s chance of breast or testicular cancer. And besides, having compounds in our environment that so clearly affect our hormonal development seems like a bad idea.

All of this is reason enough to be wary, she thinks. PCBs may have been banned more than thirty years ago, but the effects are still apparent. And there is no reason to assume that something like this couldn’t happen again.

More alert

‘The chemical industry has made other compounds to replace this one’, she says. Take for instance BPA, or Bisphenol A, a new type of softening agent. This compound can be found in plastic, building materials, packaging materials, and in tin cans. It has been known to effect fertility and the endocrine system. There are regulations about the use of this compound in food packaging and in baby bottles, but of course there is no way to guarantee that other detrimental compounds won’t be used for these purposes in the future.

‘This study has made me much more alert’, says Berghuis. ‘I’m much more conscious of the risks. They can even be passed to a third generation, because female babies already carry ova.’

And so she argues for better research and consumer awareness. And for glass rather than plastic.


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