How Plastic We’ve Become

http://www.sciencenews.org/articles/20080223/food.asp

Our Bodies Carry Residues of Kitchen Plastics

Today there is an abundant amount of items made with plastic, and we can find residues of plastic everywhere- even in our bodies. A new study shows that BPA (bisphenol A)- a building block of the most widely used plastics- laces the bodies of the vast majority of U.S. residents’ young and old.

To make (polycarbonate) plastic, BPA is linked into long chains called polymers. This clear and brittle plastic is used in things like baby bottles and food ware. When polycarbonates are used and heated, they break down and the BPA gets released into the materials they come in contact with.

In studies, where they used rodents, it shows that BPA can produce many harmful changes in things such as: problems with reproduction, bad blood sugar control, and obesity. In a new study, the urine of 2,500 people was analyzed and roughly 92% of these people hosted measurable amounts of BPA.

Typically, only small traces of BPA turned up, concentrations of a few parts per billion in urine. However, there are agents that mimic hormones, such as BPA, even a tiny bit of it can have a big impact.

In some of these studies, the concentrations were substantially higher than those that have triggered disease and birth defects. But there is a breakdown product by which BPA is excreted, which means that BPA itself may not be present in the body, although few people actually are exposed to the breakdown product. A group of scientists have estimated that the daily BPA intake to create urine concentrations that were reported should be about 50 nanograms per kilogram of body weight. But another group of scientists figured that the total is actually closer to 100 micrograms per kilogram of bodyweight. Clearly, there is a huge difference of opinion and interpretations.

Globally, manufacturers produce about 2.8 million tons of BPA every year. Many of the products made from it are used in and around the home, but it is also used in dental sealants.

A Japanese research team showed that BPA was leaked out into baby bottles and plastic food ware, so two years later manufacturers found BPA substitutes for food cans. Then, two years after that a different group of Japanese scientists found BPA residues in the urine of college students. Half came from before the switch and half came after the BPA substitute replaced it. By comparing the two values, it showed that the BPA residues were much lower (down by at least fifty percent) after the BPA was eliminated.

Kids Appear Most Exposed

Research shows that statistically, men have lower concentrations of BPA than women. But the biggest difference is in age. Children have the highest concentrations, more than teens and adults. Some scientists think this could mean that children have higher exposures or that they can’t break it down quite as efficiently. Research has also shown that urine residues of BPA decreased with increasing household income and varied somewhat with ethnicity. There was also a difference with the time of day. It would be highest in the evening, lowest in the afternoon, and midway in between those in the morning. This would comply with the fact that BPA lives only in the body for six hours and that would be consistent with food being the major source of exposure.
BPA excretion also increased in women during their pregnancy. If this is because food exposure is increased than the baby could be in danger and blood values were much higher because the enzyme that breaks BPA down only a tenth a active in babies.

This article is interesting because when you use plastics to store food you normally use it to protect it from chemicals in the air to keep it from spoiling or making you sick, but this article tells us that it, ironically, could make you sick.