Tin cans provide us with a convenient source of ready to eat olives, beans, soups, and of course, Popeye"s spinach. We"re talking inexpensive, longlived miracle foods that require no refrigeration and will keep you alive in your bunker should some cataclysmic scenario play out. We know we sacrifice freshness when we eat food from a can, but do we also sacrifice safety? Recent disclosures suggest that the plastic lining of our food cans contains hormone mimicking Bisphenol A (BPA), and some of this chemical leaches into our food.
A plastic liner for food cans is generally a good idea. You wouldn"t want the metal to make direct food contact since it could change the color and taste of the food and even impart some heavy metals with their own toxic issues. The trouble with the protective liner is that BPA migrates into the food during heat sterilization and subsequent storage. This raises a concern because BPA was originally developed in the 1930s for its ability to mimic estrogen. It was a drug candidate for women with low estrogen as a result of menopause or other conditions. However, an even stronger estrogen, diethylstilbestrol (DES), was developed around the same time and that was used instead. The disastrous consequences of giving pregnant women DES, including increased rare cancer risks for their children, served as a warning about doling out synthetic estrogens and so BPA was never marketed as a drug.
However, plastic chemists discovered something remarkable about BPA — when you string it together into a long chain, it makes a very resilient form of plastic known as polycarbonate. This launched BPA as a leading ingredient in consumer products, bringing this estrogen mimic, like a Trojan Horse, into every home in the form of baby bottles and tin can linings. Now after decades of use, the science is catching up to the reality, and the question is whether FDA, the marketplace or other forces will put this Trojan horse out to pasture.
Several regulatory and scientific bodies have recognized the issue, with the Canadian government recently banning BPA from baby bottles and tin cans that contain infant formula. On the other hand, the US FDA remains unconvinced that BPA is a real risk. This is in spite of the fact that BPA has earned the label of dangerous chemical in Canada and businesses like Nalgene and Walmart are going BPA-free with their water bottles. The science behind all this has engendered vigorous debate as some studies show effects in animals such as early puberty, increased risk for mammary and prostate cancer, and altered behavior. These effects have occurred at very low doses, in fact, close to the range of human exposure. However, other studies have not been able to replicate these findings. Some observers have pointed out that most of the negative studies were funded by the chemical industry while the positive studies were generally done at academic or government labs. So the spectrum of opinion has ranged from "maybe dangerous" to "definitely dangerous," with the concern greatest for early life exposure.
The message that has gotten out on BPA is that the hard clear plastic (polycarbonate) water bottles are not safe to drink from and so the marketplace is now featuring a variety of alternatives: aluminum and stainless steel bottles. BPA-free baby bottles are also widely available. These are good steps. But what"s missing in all this is that the main source of BPA—canned food. So, while we assuage our BPA concerns by drinking water from metal bottles, we are not doing anything about the lion"s share of exposure. This is especially upsetting when you realize that spending extra money on organic health food brands does not get you any less BPA. The one exception is Eden Organics, a distributor of canned beans; they switched over to a vegetable-based can liner several years ago on a precautionary hunch and now they are the BPA-free leader in the canned food market. I called several of the other health food brands and they were aware of the issue but made no promise to become BPA-free.
From a health point of view, estrogen(s) generally increase the risk for breast cancer in females and may create hormonal and fertility changes in males. While early life exposure is most important, the cumulative lifetime dose also matters. In an era where estrogenic pesticides, drugs and preservatives (e.g., parabens in body lotion) have been decreased in the environment and marketplace, BPA in tin cans stand out as a glaring oversight. While the scientific debate rages on, it is prudent for the public to minimize exposure to BPA. The following steps will help you move in this direction:
1)Infant formula: use powdered formula rather than the canned liquid and reconstitute it in BPA-free baby bottles. These are now widely available. 2)Canned beans: choose Eden Organics as they are the only supplier using a non-BPA can liner. 3)Canned soup: substitute dry soup mixes or frozen soup, selecting low sodium products whenever possible. 4)Canned tomato products: choose products in glass jars as the acidity from the tomatoes will likely cause extra leaching from cans. 5)Canned tuna: choose products packed in water, not oil and don"t eat canned tuna more than twice per week due to mercury and BPA. 6)Speak up: contact your canned food company to see if they have plans to switch over to BPA-free cans. If not let them know that Eden Organics has taken the lead, and they should follow. 7)Eat fresher foods instead of canned whenever possible. Frozen foods are a good alternative to canned foods as well.
GARY GINSBERG, PH.D. is a toxicologist who teaches at Yale and the University of Connecticut Medical Schools. He recently co-authored Whats Toxic What"s Not (Berkley Books, 2006), found atGreener Living with ‘Dr. G’.