Research Roundup 15 BPA

Watch out for BPA
Nancy Scanlan, DVM

What is “BPA”? Most of you probably know bisphenol A (BPA) is a chemical increasingly used in plastics, and in linings of cans used for food, including dog food. It is also present in the paper of thermal printers and copied items, and in fire retardant chemicals used in rugs and draperies. 

Originally there was not much concern about it, since the amounts present in the blood and urine of human patients was below the safe level set by FDA, and short term studies in mice did not show any obvious problems. But then scientists started noticing that BPA makes permanent changes in our DNA, often by methylation of specific genes. Not only that – the changes can be inherited. Some reproductive problems started showing up in mice also, at the low dose that was supposed to be safe.

BPA is measurable in the blood and urine of children, and there is some question about what this might be doing to their bodies, and what that will mean for their own children. BPA is found in the blood and urine of humans worldwide. 

BPA has been associated with thyroid problems, obesity, heart problems, arteries going to the heart, and reproductive problems in humans. Similar findings have been reported for fish, sheep, dogs, and cats. BPA crosses the placental barrier and is present in the developing fetus; lambs born to mothers exposed while they were pregnant were hypothyroid. BPA has been linked with hyperthyroidism in cats.

BPA is found in the linings of cans of dog food and cat food, and pets eating those foods have elevated amounts of BPA. With canned items, there is more BPA in the solids than in liquids, so pouring off the liquid does not offer much protection. BPA is also found in plastic toys, and leaches out when dogs chew them, especially when lots of saliva is produced.

BPA is found in plastic containers as well as in can liners. Look for “BPA free” plastic bottles if you buy moist foods or liquids in plastic containers. Glass is BPA free, but the liner on the lid might have BPA. For a list of human foods that are sold in BPA free cans, see

For pet foods, it is harder. The problem is in canned foods, not kibble in bags. Smaller 3 and 5.5 oz cans are generally BPA free, but it can be difficult for a company to find large cans that are BPA free. Trader Joes says all their pet foods are BPA free. It has been reported that Halo, maker of Spots Stew, is seeking sources of BPA free cans for all their foods. 

In a survey done 6 years ago, the following companies claim their pet foods are in BPA-free cans:

Blue Buffalo
Chicken Soup

Even the AVMA is concerned about BPA in dogfood cans. This week they noted reports from a study at the University of Missouri about the amount absorbed by dogs when eating food from cans with liners containing BPA. If you see a can with a white plastic lining, that can is releasing BPA into the food. 

So be diligent about buying human food in the right kind of cans, or use fresh or frozen instead. Support the companies who sell BPA-free foods. Watch for other sources of BPA and minimize exposure to those. And watch out for sources you might not be aware of: Those shiny receipts you receive from cash registers when you finish shopping are also a source of BPA.


See the references at