Post by Kirsten Beynon
In the 1950’s there was a revolution in the kitchen. Tupperware had created a fantastic set of plastic products for use in the kitchen, and you bought them at parties. Convenience and fun in one easy sales package. And a whole movement was created.
But is plastic storage for food all that it’s cracked up to be?
There are more than 30 types of plastics that have been used for food packaging: polyethylene, polypropylene, polycarbonates and polyvinyl chlorides.
Certain chemicals are required to keep plastics soft and flexible. These are called plasticizers, and the softer the plastic, the more plasticiser it generally contains (1). As plastics age, the levels of these plasticisers decreases, leading to brittle plastic. All types of plastic contain these chemicals.
So where do they go?
Well, some will evaporate into the air (that’s what ‘new car smell’ is) and you might breathe them in. They are all fat-soluble, so will leach into fat containing food if they are in contact with it. Some will also leach into water that is stored in plastic. There is more leaching into fatty or acidic contents and when heated.
What’s the deal with BPA (Bisphenol A)?
Well, BPA is found in polycarbonate plastic, used for food containers, drink bottles, baby bottles and as a liner in some aluminium food cans.
While the FDA in the US and Food Safety New Zealand would like to reassure us that the levels of BPA that we are exposed to are safe (2), the evidence suggests that this is not the case.
More than 90% of the monitored populations (USA and Canada) tested positive for BPA in their urine. 90-99% of exposure to BPA is from food in both adults and children (3).
Research shows that BPA is a hormone disruptor, affecting oestogen receptors, thyroid hormone receptors and others (4 & 5), and causing problems at the low doses that are commonly seen in the population.
Suspected negative effects of BPA are: reproductive problems (male and female), cardiovasular effects, the development of diabetes, obesity and metabolic syndrome, immune effects (4), increased breast cancer risk, miscarriage, low birth weight, brain development and behavioural problems, particularly in boys, childhood asthma and thyroid problems (6).
So BPA got all this bad press and was removed from many kitchen plastics, baby bottles and drink bottles. You may have noticed that the BPA-free plastics look and feel just like the old ones. You might hope that these plasticisers like BPA were replaced with safe and inert ones. Well, they weren’t. BPS and BPF are used in place of BPA, and as they are chemically very similar, their effects are very similar (7).
‘BPA-free’ is a con.
BPA isn’t the only plasticizer that might cause you problems. Cling film, particularly commercial (caterers and supermarket) has some nasties in there too.
So what can you do about it?
You can’t eliminate these things entirely without removing plastic from your life entirely. And that is almost impossible.
1. Pvc.org,. (2014). Plasticisers - PVC. Retrieved 17 June 2015, from http://www.pvc.org/en/p/plasticisers
2. Fda.gov,. (2015). Bisphenol A (BPA): Use in food contact application. Retrieved 17 June 2015, from http://www.fda.gov/NewsEvents/PublicHealthFocus/ucm064437.htm
3. Teeguarden, J. G., & Hanson-Drury, S. (2013). A systematic review of Bisphenol A “low dose” studies in the context of human exposure: a case for establishing standards for reporting “low-dose” effects of chemicals. Food and Chemical Toxicology : An International Journal Published for the British Industrial Biological Research Association, 62, 935–48. doi:10.1016/j.fct.2013.07.007
4. Geens, T., Aerts, D., Berthot, C., Bourguignon, J.-P., Goeyens, L., Lecomte, P., … Covaci, A. (2012). A review of dietary and non-dietary exposure to bisphenol-A. Food and Chemical Toxicology : An International Journal Published for the British Industrial Biological Research Association, 50(10), 3725–40. doi:10.1016/j.fct.2012.07.059
5. Foodstandards.govt.nz,. (2015). Bisphenol A (BPA). Retrieved 17 June 2015, from http://www.foodstandards.govt.nz/consumer/chemicals/bpa/Pages/default.aspx
6. Rochester, J. R. (2013). Bisphenol A and human health: a review of the literature. Reproductive Toxicology (Elmsford, N.Y.), 42, 132–55. doi:10.1016/j.reprotox.2013.08.008
7. Rochester, J. R., & Bolden, A. L. (2015). Bisphenol S and F: A systematic review and comparison of the hormonal activity of bisphenol A substitutes. Environmental Health Perspectives, 110(4), A174.