BPA, Bisphenol A, has long been the subject of scientific studies of its deleterious effects on the health of humans and animals. Anne Marie Helmenstine, Ph.D., About.com Guide to Chemistry, wrote in 2010 about the fact that the Canadian government had declared BPA to be a toxic chemical.

BPA is a chemical commercially found not only in the lining of pop-top cans, but as 'polycarbonate plastics" in plastic bottles and clear plastic film.

One of the clues that a plastic bottle may be made of BPA, is the number inside the symbol on the bottom of the bottle. The number "7" refers to "all others (materials," which includes BPA. The toxicity of the latter two increases when the products are subjected to heat, such as leaving a plastic drink bottle in a hot vehicle, or microwaving food in a plastic container. I've checked several plastic bottles at home and the insulated cup I use for soft drinks (two layers with an air space between) has the numeral 7 on the bottom. We have been unknowingly surrounding ourselves with BPA for decades.

AVMA Links BPA to Feline Hyperthyroidism

In 2004 the American Veterinary Medical Association published the results of a 20 year study involving thousands of cat, including 3,470 hyperthyroid cats. While the study found that feline hyperthyroidism was definitely more often found in older cats, there also was evidence that BPA was a factor. The published Conclusions: "These findings suggest that the increasing prevalence of feline hyperthyroidism is not solely the result of aging of the cat population and that canned foods may play a role. (J Am Vet Med Assoc 2004;224:879-886).
My cat Joey was diagnosed as hyperthyroid in 2011, and after a short time on Tapazole, to which he became allergic, he had radioactive iodine therapy.

Now I am beginning to wonder if the canned cat food he had been eating the previous nine years had been contaminated with BPA, and could have been at least partially to blame for this illness. Although I prided myself on researching and using only the finest food products possible, I had used some of the foods which likely at that time had cans with BPA lining.

I blame my ignorance now. As early as 1997, Mary Shojan, the Guide to Thyroid disease for About.com, posted a blog entry about the hazards to cats of "pop-top" cat food cans' BPA lining. Mary wrote, " research came out a few years ago, indicating that the pop-top cans on cat food -- actually, the chemicals lining the pop tops -- can pose a thyroid danger for cats, contributing to risk of feline hyperthyroidism."

Had I been alert enough to find that reference, I could have investigated further and possibly saved Joey the risk of getting thyroid disease with its subsequent threat of hypertrophic cardiomyopathy.
I could also possibly have saved Bubba, (third photo) who was diagnosed with HyperT around early 2001, and eventually given I^131> treatments.
I'm taking this whole issue very personally, and I hope everyone who reads this article who has fed their cats canned food over the past two decades will take it personally.

BPA-Lined Pet Food Containers Okay With FDA

While a number of studies have been done about the effect of BPA on human health, little can be found about animals, other than rats used in research. Since humans and cats are both susceptible to so many of the same medical conditions, I think it's fair to say that what is toxic to us just might have an adverse effect on our cats. Cited here are a few of these human food studies, so those interested can read further.

• FDA Scientists Find BPA in Canned Foods
  From the Environmental Working Group Study: Wednesday, December 31, 1969, Washington, D.C. -- A new study by the federal Food and Drug Administration has found canned green beans contaminated with as much as 730 parts per billion of bisphenol A, a synthetic hormone and component of epoxy can linings.
• Environmental Working Group Study
  In March of 2007, the Environmental Working Group published the results of an independent study on tests of canned food in several supermarkets.
• NIH on BPA:
  The National Institute of Environmental Health Sciences, a division of the U.S. Department of Health and Human Services, provides a series of questions and answers on the effects of BPA on human health, and what can be done to reduce potential harm.

The FDA Has Only Outlawed BPA in Baby Bottles

In 2012 the New York Times published a news article titled, F.D.A. Makes It Official: BPA Can't Be Used in Baby Bottles and CupsWASHINGTON - The Food and Drug Administration said Tuesday that baby bottles and children's drinking cups could no longer contain bisphenol A, or BPA, an estrogen-mimicking industrial chemical used in some plastic bottles and food packaging. Similar articles were published in The Huffington Post, The Wall Street Journal, and CBS News, among others.

The FDA was a bit less forthcoming. Although I could locate nothing on the FDA Website dated in July 2012 about this "ban," another lengthy file, updated in March, 2013, noted in part, "FDA is taking reasonable steps to reduce human exposure to BPA in the food supply. These steps include: supporting the industry's actions to stop producing BPA-containing baby bottles and infant feeding cups for the U.S. market. This was followed by a caveat, FDA is not recommending that families change the use of infant formula or foods, as the benefit of a stable source of good nutrition outweighs the potential risk from BPA exposure. The entire file repeatedly used the word, "supporting", e.g., supporting the industry's actions, supporting efforts to replace BPA or minimize BPA levels in other food can linings, supporting a shift to a more robust regulatory framework for oversight of BPA, and supporting ongoing studies.

It appears to this consumer that the FDA is taking a laissez faire attitude toward this whole issue. While the FDA continues to insist that BPA is not particularly harmful, it is willing to let others do the work of proving BPA's toxicity before taking any official action. Some pet food manufacturers are stating when asked by consumers that their can linings "contain BPA in the safe and acceptable level established by the FDA," or some similar statement.

Which Cat Foods use BPA-Lined Cans?

I am indebted to Susan Thixton,Pet Food Safety Advocate, and writer/manager of the website, Truth About Pet Food, both for the vast wealth of information on her site, as well as for bringing the issue of BPA to my attention. Susan works tirelessly on behalf of cats, dogs, and other animals, and she and an unknown number of volunteers personally called and/or emailed pet food companies' customer service departments to inquire about the use of BPA lined cans for their pet food. In fairness to Susan Thixton, I will only cite a few of the products on her list which I've bought or mentioned on my website.
Companies Using NO BPA Linings

• Blue Buffalo
• Canidae
• Evangers

Companies With BPA Linings

• Drs. Foster & Smith (All Cans)
• Newmans Own Organics Pet Food
  3 oz beef, beef & liver and liver (from Uruguay) have BPA. All others are BPA free.
• Natura (Innova, California Naturals)
  BPA in 13.2 oz. steel cans

A few other companies gave conflicting replies by one rep or another. For a more complete and thorough list, please see the Truth About Pet Food website. While you are there, I recommend checking out some of the other content Susan writes about on an almost daily basis, and consider signing up for both her free newsletter and her Petsumer Report, which is only $17.95 for a one year subscription. It's the best 18 bucks I've ever spent, to be able to read of the ingredient details and ratings of over 2,500 dog and cat foods and treats.
Volunteers Welcome

If you are as concerned as I about the food our cats eat, I hope you will do your own investigation into various brands of cat food your cats eat. While you can read the ingredients on the labels or online, government regulations do not require, nor do manufacturers share the information about BPA lining in their cat food cans. You would need to contact them by email or telephone. I'd appreciate it if you would pass that information on to me by email. I can be reached at cats(at)aboutguide.com. It's all about our cats, after all.