To answer your great question and give you guidance as to how you can minimize you exposure to BPA, we wanted to first describe what this compound is including the health effects that it may have. Then we'll explore how common it is in canned foods, specifically organic canned foods, and give you our recommendations as to how you may still be able to enjoy the convenience of organic canned beans while promoting your Healthiest Way of Eating.
Bisphenol A — often abbreviated as BPA — is a clearly problematic toxin from the standpoint of the ecosystem and ocean life, and a somewhat controversial toxin with respect to human health. Known from a chemical perspective as 2,2-bis(4 hydroxyphenyl)propane, BPA is widely dispersed in the environment.
There are many potential sources of exposure to BPA completely unrelated to food. BPA is often used in the manufacture of polycarbonates plastics, epoxy resins, and flame-retardant materials. It can be found in adhesives, polycarbonate plastics, automobile parts, laminated products designed to be bullet proof, some fax paper, and some CDs.
Within the world of food, two key sources of exposure to BPA are polycarbonate plastic water bottles (usually labeled with the Number 7 recycling symbol), and resin-based can liners that are used to reduce spoilage of canned foods. Baby bottles can also be a problem in terms of BPA exposure.
BPA is a bioactive compound that is able to bind onto an estrogen receptor on the nucleus of a cell and modify its function. BPA seems able to cause changes in some types of cell functions at very similar concentrations to the naturally produced estrogen molecule called estradiol. Especially during the fetal period before birth, BPA is of special concern with respect to later life changes in the risk of chronic disease, reproductive ability, and cancers of the breast and prostate. BPA is often referred to as an "endocrine disruptor" because of its ability to disrupt estrogen receptor activity, alter fertility, and increase risk of reproductive system-related cancers later in life. These health dangers posed by BPA exposure are clearly established with respect to fish and many ocean-living creatures. However, the human risks involved with exposure to BPA at food-related levels remains a matter of substantial debate within research studies. Some of the debate over BPA exposure and BPA risk may eventually turn out to hinge upon the health status of individuals exposed to BPA and their ability or inability to detoxify this toxin compound. Most of the BPA we get exposed to can be detoxified through a process called glucuronidation, and individuals can differ greatly in their ability to carry out this detoxification process.
Research published in November 2011 in the Journal of the American Medical Association showed the ability of BPA in canned food to increase urinary levels of this contaminant. In a small study involving 75 participants, one 12-ounce serving of canned non-organic soup per day over the course of 5 days was enough to raise urinary BPA levels by approximately 1000%. While this finding does not shed light on the health consequences of BPA exposure, it does show the very likely ability of everyday BPA intake from canned soups to raise levels in our body.
The Environmental Working Group (EWG), a not-for-profit organization headquartered in Washington, D.C. that routinely issues reports on food-related toxins in the United States, released a report on bisphenol A in 2007. In their laboratory testing of 27 nationally marketed name-brand canned foods, the EWG found about half of all canned foods (55/97 cans) to contain BPA. The EWG further estimated that about 10% of all canned foods contain excessive levels of BPA.
To the best of our knowledge, BPA is not a prohibited toxin in the national organic foods legislation. Because polymers containing BPA are listed as "inert pesticide ingredients" in the U.S. Environmental Protection Agency's "List of Inert Pesticide Ingredients" updated in August 2004, this potential toxin does not appear to be strictly prohibited in the canning process used for certified organic foods.
In an article published in the summer of 2000 in Terrain magazine by the Ecology Center in Berkeley, California, author Andrea Jones reported contacting eight organic products companies. Her findings noted that many of them manufactured canned organic products containing BPA.
Yet, this doesn't mean that all cans of organic foods (nor even cans of non-organic foods) contain BPA. To find out if your favorite canned organic foods are manufactured using BPA-containing cans you will need to call the manufacturer. This will help you determine which products do and do not contain BPA.
Given the EWG's 2007 estimate of approximately 10% risk of BPA exposure from all canned food manufacturers, and the availability of BPA-free packaging from some organic manufacturers, we do not believe there is a reason to categorically avoid all canned organic foods when setting up a meal plan. But we do believe it's important to reduce your BPA exposure as much as possible.
To be completely sure that you are not being exposed to any BPA from canned foods, your best bet is to factor in a little more time to your meal preparation process and avoid canned foods altogether. Short of this step, as mentioned earlier, you can call the toll-free number found on the packaging of most canned organic products (or found on the manufacturer's website) and ask for the status each particular canned food with regard to BPA.
Environmental Working Group. (2007). Bisphenol A: Toxic Plastics Chemical in Canned Food. Environmental Working Group, Washington, D.C. Available online at: http://www.ewg.org/reports/bisphenola.
Lyons G. (2000). Bisphenol A: a known endocrine disruptor. WWF European Toxics Programme Report. European Toxics Programme, Surrey, UK.
Crain DA, Eriksen M, Iguchi T, Jobling S, Laufer H, LeBlanc GA, and Guillette LJ Jr. An ecological assessment of bisphenol-A: evidence from comparative biology. Reprod Toxicol. 2007 Aug-2007 Sep 30; 24(2):225-39.
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Maffini MV, Rubin BS, Sonnenschein C, Soto AM. Endocrine disruptors and reproductive health: the case of bisphenol-A. Mol Cell Endocrinol. 2006 Jul 25; 254-255:179-86.
Tsai WT. Human health risk on environmental exposure to Bisphenol-A: a review. J Environ Sci Health C Environ Carcinog Ecotoxicol Rev. 2006; 24(2):225-55.
Welshons WV, Nagel SC, vom Saal, FS. Large effects from small exposures. III. Endocrine mechanisms mediating effects of bisphenol A at levels of human exposure. Endocrinology. 2006 Jun; 147(6 Suppl):S56-69.
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