For all the disadvantages that plastic has, one cannot deny that its versatility is matched by very few other materials. One such use plastic finds is in food packaging. It is not uncommon to find plastic containers in homes – simply because unlike metal and glass, they can be used to both store as well as microwave food and do not break easily.
However, according to several studies, eating from plastic containers exposes you to substances that are added into the plastic to make it more stable and easier to process.
Two of these substances are phthalates and bisphenol-A (BPA), which are known to be harmful to human beings. According to a publication on the Harvard Medical School site, these are “endocrine disruptors”. These mimic hormones in the human body, and the effects are not good. Exposure to BPA has also been related to higher cancer risk, and health hazards in pregnant women and children.
The implications are alarming, but does this mean that you should get rid of all the plastic containers in your kitchen, and even those labeled as microwave safe?
We spoke to experts to find out.
How BPA and phthalates affect the human body
Avantika Srivastava, a freelance writer in Bengaluru with masters in microbiology, explains how these plasticizers affect the human body. She confirms that while Diethylhexyl phthalate (DEHP), contained in some plastics, is a toxic carcinogen, BPA interferes with human hormonal function.
“Bisphenol A affects the genes related to the thyroid hormone. BPA can ultimately decrease thyroid hormone receptor (TR) activity, which then decreases the level of thyroid hormone binding proteins. By affecting the thyroid hormone axis, BPA exposure can lead to hypothyroidism and premature growth in children,” she explains.
Avantika adds that BPA can also affect physiological levels and metabolism of sex hormones. “It often acts as an antiandrogen or as an estrogen, which can cause disruptions in gonadal development and sperm production.” Gonadal development is the development of gonads, which are sex glands responsible for producing gametes (sex cells) and sex hormones.
Making informed choices
Magesh Nandagopal, a scientist with CSIR-NCL (Council of Scientific Industrial Research – National Chemical Laboratory) begins by saying that there are many different kinds of plastic. “People don’t have this distinction between different kind of plastics; for most, it is just a monolith. All of them are made from different raw materials and have different properties,” he says.
He acknowledges that while the use of phthalates is indeed problematic and can harm human health, it is not used in all plastics, even more so recently.
Magesh adds that in food-grade plastics, PET bottles, and microwave safe plastic containers, bought from trusted sellers and companies should not be a cause for worry. “But if you put plastic containers which are not specifically marked microwave safe into the microwave, there is no guarantee how it will change the properties of the material. That’s like putting plastic into fire and saying it’s melting,” he cautions.
There is, however, a lack of standardisation when it comes to plastic production. This means that the plastic used in some containers, unlike those of trusted manufacturers, could be mixed with recycled plastic or plastic that is not processed properly.
Magesh says that it is a good practice then to look for a recycling code on the packaging and a number along with it. “Each number refers to a particular plastic. That is one way for you to figure out what kind of plastic you’re using,” he explains.
Is existing research enough?
Meanwhile, Dr Bruno, a Chennai based neurosurgeon, believes that existing research is enough to establish that eating and drinking from plastic containers and vessels should be avoided entirely.
“Studies have shown phthalates to cause endocrine disruption, and have hepatotoxic (liver damage) teratogenic (affects fetus, producing congenital abnormalities in the child), and carcinogenic properties. But their usage continues due to their attractive chemical properties, low production cost and lack of suitable alternatives,” he tells TNM.
He asserts that it is time we go back to old practices of using metal containers, vessels and tiffins.
But Dr Aruna Muralidhar, a Bengaluru based gynaecologist differs. She points out that the evidence gathered in most of the existing research is indirect, and there have been no large scale human studies.
However, she also warns that some of the health issues hypothesized to be associated with BPA and phthalate contamination in food also run the risk of being passed on to the next generation. “Things like hormonal imbalance are on the rise, no doubt. But we must keep in mind that there are a host of factors responsible for any condition – stress, pollution, lifestyle and so on,” she says.
According to Centres for Disease Control and Prevention too, while some types of phthalates were found to adversely affect reproductive system of laboratory animals, “more research is needed to assess the human health effects of exposure to phthalates.”
That being said, Dr Aruna concedes that a doctor would hardly attribute fertility or hormonal issues in a patient to food consumption from plastic containers, though they should be mentioning it as a possible cause. “We should perhaps start having pamphlets in clinics which prime people on the existing research on BPA and phthalates. Just so that they are aware and can make informed choices,” she suggests.
Plastic can enter the human body in many ways
It is also important to note that plasticizers don’t find their way into the human body through food alone. In fact, phthalates can be found in the most inconspicuous things – right from household cleaners to fragrances and personal care products.
“It makes sense that when hot food is put into containers which are not food grade, the chemical properties of the container would change with the heat. However, we need to keep in mind that plastic and polymer contamination entering the human body has a host of factors behind it – even from some cosmetics we use,” says Dr Aruna.
Avantika adds that there even the plastic scrubbers and micro beads found in facial scrubs, toothpaste, body washes might look harmless, but their tiny size allows to enter the human body and cause various metabolic dysfunctions.
“Different plastics like styrofoam breaks into smaller parts, polystyrene components in it sink lower in the ocean, hence the pollutant spreads throughout the sea column,” she adds.