Hormones, Mimics and Canned Food

Canned foods have plastic liners.  If they didn’t we’d probably need to worry about metals leaching into foods.  The liners serve a protective function.  Unfortunately they may pose risks of their own.  Bisphenol A is commonly known as BPA.    It is produced in large quantities for use in plastic products including the linings of tin cans, water bottles, and, until very recently, in baby bottles.

Two young boys workout at a CrossFit for Hope fundraiser.

There are some pretty serious concerns with BPA. Structurally, it resembles estrogen, the female sex hormone. The human body reacts to it in a manner that resembles its reaction to estrogen. BPA has been tested in lab animals.   Human research has shown that what is happening to lab animals may be happening to people through every day use of canned food and other food packaging, plastic products, contaminated drinking water, and by breathing in dust.  Most people (more than 90%) are believed to be exposed regularly (Lakind & Naiman 2008).

There is also some evidence that BPA can speed growth of prostate cancer cells, interfere with testosterone production and disrupt thyroid hormone function. (Vom Saal & Hughes 2005). People with higher exposures have been found to be more likely to develop cardiovascular disease even when adjustments were made for obesity, level of activity and intake of fruit and vegetables (Melzer et al.) They are also more likely to develop diabetes (Meltzer et al. again).

There are additional concerns for children. Kids whose urine contained higher than average levels of BPA metabolites also had lower IQ scores (This research hasn’t been published yet, but the data was presented at a meeting). The effect was more noticeable in boys. These are good reasons to avoid canned and packaged foods. There are, of course, other chemicals in plastics that also end up in foods and in people. BPA is only one. Here in a nutshell is why you should eat fresh food instead of canned. Frozen foods are probably a safe bet too:

 • BPA is an estrogen mimic
 • It may lower testosterone levels
 • It may increase risk of prostate cancer
 • It may increase risk of diabetes
 • It may increase risk of cardiovascular disease
 • It may be harmful to infants and children.

If you are interested in reading more about how chemicals and the environment impact health we recommend reading Environmental Health Perspectives.  This is a very well-respected journal.  You can read all articles for free online.

Melzer D, Osborne NJ, Henley WE, Cipelli R, Young A, Money C, McCormack P, Luben R, Khaw KT, Wareham NJ, & Galloway TS (2012). Urinary bisphenol A concentration and risk of future coronary artery disease in apparently healthy men and women. Circulation, 125 (12), 1482-90 PMID: 22354940  

Lakind JS, & Naiman DQ (2011). Daily intake of bisphenol A and potential sources of exposure: 2005-2006 National Health and Nutrition Examination Survey. Journal of exposure science & environmental epidemiology, 21 (3), 272-9 PMID: 20237498 

vom Saal FS, & Myers JP (2008). Bisphenol A and risk of metabolic disorders. JAMA : the journal of the American Medical Association, 300 (11), 1353-5 PMID: 18799451

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