The study, which appeared this week in the journal Environmental Health Perspectives, concluded that such packaging is the major source of human exposure to BPA and other endocrine disrupting chemicals (EDCs) such as DEHP (bis(2-ethylhexyl) phthalate).
Scientists also noted that once participants returned to their regular diets, BPA levels returned to normal.
Trade body NAMPA (North American Metal Packaging Alliance) dismissed the research, saying its most significant finding was it provided evidence of how quickly humans metabolize and excrete BPA.
Methodology and results
Scientist Julia Green Brody et al chose 20 participants in five US families based on their self-reported use of canned and packaged food. Subjects ate their usual diets followed by consumption of exclusively fresh foods prepared by external caters over the space of three days – in what the researchers labelled a “dietary intervention”. They then resumed their usual diets.
Scientists collected 11 urine samples over eight days to measure variations in the levels of the chemicals before, during and after the dietary change.
They found that levels of the EDCs “decreased significantly” during the fresh food intervention – with BPA values falling by 66 per cent and DEHP metabolites by between 53 and 56 per cent.
“Participants’ reports of their food practices suggested that consumption of canned foods and beverages and restaurant meals were the most likely sources of exposure to BPA and DEHP in their usual diets, since they reported limited use of polycarbonate water bottles, frozen prepared foods, and microwaving in plastic”, said the scientists.
They added the intervention did not eliminate all dietary sources of exposure as this can also occur through the presence of BPA and DEHP in the environment.
But the research concluded: “Results of this study suggest that removing BPA and DEHP from food packaging will significantly decrease exposure for adults and children.”
While the authors cited the large body of research linking BPA to health problems, they did not indicate that pre or post intervention levels of the chemical exceeded legal limits.
NAMPA said BPA levels detected in the study were comparable to those used by regulatory bodies across the world in their declaring the substance posed no health hazard in food packaging.
“An average adult would have to consume several hundred cans of food a day to exceed those ‘tolerable daily levels’ established by regulatory bodies,” it added.
The researchers however noted the Food and Drug Administration’s (FDA) recommendation in January 2010 for humans to reduce BPA exposure. This included the federal regulator supporting efforts to replace or minimise BPA levels in food can linings.
But the metal packaging trade association rejected the research - declaring it to be “neither news nor a toxicological study that provides any insight to the scientific evaluation of BPA”.
It said: “The survey does, however, provide further evidence of how efficiently the human body metabolizes and excretes BPA. It clearly demonstrates that BPA is rapidly processed and eliminated in urine rather than accumulating in the body.”
Food Packaging and Bisphenol A and Bis(2-Ethyhexyl) Phthalate Exposure: Findings from a Dietary Intervention by Ruthann A. Rudel, Janet M Gray, Connie L. Engel, Teresa W. Rawsthorne, Robin E. Dodson, Janet M Ackerman, Jeanne Rizzo, Janet L. Nudelman, Julia Green Brody; doi: 10.1289/ehp.1003170 (available at http://dx.doi.org/)