There is mounting evidence that exposure to a widely used chemical called bisphenol A is associated with an increased risk of obesity, diabetes, and metabolic syndrome.  A recent study reveals that eating canned soup for just 5 days can dramatically increase exposure to this potentially dangerous chemical.
Bisphenol A is a widely used chemical, found in a variety of products ranging from plastics to cash register receipts.  Most of our exposure is thought to be through food; in addition to being present in many water bottles and plastic food storage containers, it is also present in the interior epoxy coatings of many canned goods used to prevent corrosion.
The study was eloquently simple.  Seventy-five students and staff at the Harvard School of Public Health were each asked to eat soup for lunch for 5 consecutive days, and were randomly assigned to eating either canned soup, versus homemade soup from scratch. The following week, they ate soup each day for lunch once again, but they ate the opposite kind of soup from what they had eaten the week previously (researchers: thereby providing a randomized, single blinded, crossover design). 
The results were, in my opinion, quite astonishing: the researchers found that the bisphenol A levels in the urine were nearly twenty times higher after a week of canned soup consumption, compared to after homemade soup consumption.  Further, the urine bisphenol A levels after the canned food week were 60% higher than the higher end of urine bisphenol A levels noted in the general population. 
The study did not test the bisphenol A levels in the blood, so we don’t know if these people quickly cleared the bisphenol A from their systems, or whether the bisphenol A levels in their blood or other tissues was also elevated, or for how long.  That being said, the study does clearly show that just 5 days of eating canned soup dramatically increases exposure to this potentially harmful compound. 
Let’s hope that this study gives an extra push towards using bisphenol A – free linings to canned goods, as well as yet another reason to cook and enjoy healthy food made at home!  
Thanks to my friend and colleague Jon for pointing out this study!
Dr Sue Pedersen © 2012 

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