Wednesday, 21 December 2016

The toxicity of microwaved plastic

Throughout our lives we resort to microwaving food basically everyday without fully paying attention to the dangers associated to the likelihood of their leaking toxicants (due to container degradation). Such degradation stems from, for example, overheating material that does not stand such high temperatures and releases their degraded products onto/into the food within their volume.

One of these products is the famous bisphenol A, very recently involved in a reported scandal of potential harm for babies due to their presence in plastic feeding bottles. And that prompted many scientific studies on the toxicity of such materials to babies when plastics are used (not obligatory heated) in feeding young age children. But the danger potentials are a widespread exposure of all of us to these toxicants. But let's try and understand a bit better what is under the spotlight in this scenario.

What is the problem?

The problem is that a big percentage of the plastics we use as containers or vehicles in our food chain use bisphenol A (BPA) and poliethilenes in their making process. BPA is a material used in the making of polycarbonate and epoxy resin liners and alongside poliethilenes behaves as an endocrine disruptor with health impacts on growth, sexual maturation and even neuronal development [1]. If I am not wrong I wrote about it here, here and also here (visit for some extra goodies).

Are there studies about it?

Numerous to be fair! But for the sake of the example let me just 'cherry pick' one conducted at a Granada University Hospital (Southern Spain) with a cohort of mother-son pairs as a population. This population was presented to an estimated intake of BPA of around 1.1 μg per day, and no relationship was found between BPA exposure and maternal socio-demographic variables studies, as well as newborn characteristics [2]. And you know why? Because these mothers were fed mostly fish and juice cans. However, pregnancy exposure to low levels of BPA is still a concern.

What products should we be worried about?

In addition to BPA anything from plastic components like:

- phtalates (used to increase flexibility of plastics) [3];

- polybrominated diphenyl ethers (PBDE) (used as flame retardants in products that are in contact with plastics; PBDE shows anti-androgen activity and disrupts thyroid hormone homeostasis) [4] [5];

- tetrabromobisphenol A (TBBPA) that is almost like a super-fusion of the shared properties of BPA and the brominated flame retardants (PBDE) - this is a carcinogenic substance with a keen eye for attacking the thyroid [5].

- alkylphenols (used as antioxidants in products made from plastics and rubber) - studies focusing on these found them to alter the mammary gland in rats [6].

Big names confuse me, any simpler way to recognise them?

Well, actually there is! Look for the image up there and read it through carefully. In addition, you can also use this image here as aid for a quick idea of what you are about to lick!

Any Alternatives?
Yes, resort to the good 'old' clear glass and white ceramic when you can't find the dangerous triangle numbers mentioned above. Resort to conserving food in glass and ceramic containers rather than the plastic ones as the issue is not solely related to heated plastic, but dangerous substances leaking from plastic that has been in contact with your food. Scratched plastic containers are also of concern.

Don't know if I believe that? Used plastic all my life and still have my balls!

Hard to believe? No problem, trust Harvard then. Harvard Medical School produced a fantastic article that works as a family health guide softly covering all that has been discussed herein and some extra tips for the family. Just access it here.

Before I go just wanted to say that this article was recommended by my mum. I wrote it after she asked me to stop using plastic like a thousand times. I am on the way to do it, mum, now you can stop sending me those scary emails. Cheers all.

[1] Erler, C. and Novak, J. (2010). "Bisphenol A exposure: Human risk and health policy". Journal of paediatric nursing, 25(5), pp. 400-407.

[2] Mariscal-Arcas, M., Rivas, A., Granada, A., Monteagudo, C., Murcia, M. A. and Olea-serrano, F. (2009). "Dietary exposure assessment of pregnant women to bisphenol-A and microwave containers in Southern Spain".Food and chemical toxicology, 47(2), pp. 506-510.

[3] US Department of Health and Human Services, 14th Report on Carcinogens (RoC) (2016), CAS NO. 117-81-7, Di(2-ethylhexyl) Phtalate.

[4] Polybrominated diphenyl ethers , United States Environmental Protection Agency, [], last visited on the 21st of December 2016, last update unknown.

[5] Talsness, C. E., Andrade, A. J. M., Kuriyama, S. N., Taylor, J. A., Saal, S. F. (2009). "Components of plastic: experimental studies in animals and relevance for human health". Phylosophical transaction of the Royal Society of Biology, 364(1526), pp. 2079-2096.

[6] Alkylphenols, Breast Cancer Fund, [], last visited on the 21st of December 2016, last update unknown.

Bottom image kindly taken from Safe Plastic Nubers (Guide), Baby Green Thumb, [], last visited on the 21st of December 2016, last update on the 6th of June, 2011.

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