Protecting our cats from the elephant in the canned cat food room (hyperthyroidism)

JGS_ShannonWithKitty_crop-300x276 Protecting our cats from the elephant in the canned cat food room (hyperthyroidism) PBDE feline hyperthyroidism BPA-free cat food BPA

Good grief – why is feline hyperthyroidism so common these days? Is there anything we can do about it on the natural end of the spectrum?

As your fellow concerned cat lover, let me share the most useful insights and resources I’ve unearthed about all this, including which foods appear to be the safest bet.

This disease is one of the top reasons cats end up at the vet now, and we really want to avoid the dangerous weight loss and heart problems associated with it.

Meeting the elephant: a link to canned cat food?

Canned cat food and feline hyperthyroidism: some researchers suggest a link. What’s going on here and what to do?

We love wet food for how it protects cat kidney and urinary health, so we need canned food options we don’t have to worry about.

Suspect #1

It appears the first suspect in canned food is a substance used to line many cans: Bisphenol A (BPA). It’s classified as an endocrine disrupter by the Environmental Protection Agency. There’s a serious movement to get it out of human foods.

In 2004 the Epidemiologic study of relationships between consumption of commercial canned food and risk of hyperthyroidism in cats, noted the following:

  • Consumption of canned (vs dry) food at various times throughout life was significantly linked to a greater risk of feline hyperthyroidism. The risk increases as cats get older.
  • Rodent studies confirmed that BPA “interference with triiodothyronine binding may lead to…increased thyroid hormone production.” In other words, hyperthyroidism.

Other studies, including the 2009 study, Risk factors for feline hyperthyroidism in the UK, had similar conclusions.

Suspect #2

A 2007 study also looked at the possibility of the endocrine disrupting PBDE, a flame retardant, playing a role in the rise of hyperthyroidism in cats.  PBDEs are found in particularly high concentrations in larger fish higher up the food chain, like salmon and whitefish, according this ScienceDaily article.

PBDE appears to be less prevalent in wild salmon than farmed salmon, thank goodness.

Just a guess: It may be that these two chemicals together, even more than one alone, increase risk.

Dealing with the elephant: smarter canned options

Because wet food is so much better for our cats’ kidney and urinary health, we are sticking with it.

So to decrease the threat of feline hyperthyroidism, here’s what we do:

  • We buy only BPA-free canned cat food. The Today’s best cat foods page now specifies which cans are BPA-free. Also, all the frozen and raw packages are BPA-free – they aren’t in cans.
  • To avoid PBDEs, we feed “large fish” cat food no more than 1 -2 times per week on average. When we do serve large fish, we choose something from Tikicat because they favor clean, ecological sources of fish.

When I have time, I also make carefully formulated homemade cat food part of our cat’s diet. (Not too often lately.)

Resources if your cat is diagnosed with feline hyperthyroidism

Exploring alternatives

  • Homeopathic Treatment of Feline HyperthyroidismHomeopathic vet Peter Dobias explains a study demonstrating success with homeopathic treatment. You may wish to contact him for more information.
  • Dr. Karen Becker’s Feline Hyperthyroidism article She outlines the conventional options, but advises we should preventatively check thyroid levels after age 10 so that if you  catch it early enough you can try a more gentle alternative like homeopathy first.
  • You may also want to examine an herbal remedy called Thyroid Support Gold. I don’t know much about it, so this is something to talk to your vet about. There are reports of it helping with symptoms – increasing weight gain and calm – but I don’t know whether it changes the bloodwork results.

Your suggestions?

If you have other good resources, if your cat has had success with any treatments, or if you have cautionary tales that could help others, I hope you’ll share here.

Love to hear your thoughtful thoughts! Leave a reply...


  1. Without a doubt, the very best, most thorough online source for info regarding feline hyperthyroidism is a blog owned and written by Dr. Mark Peterson, the world’s leading veterinary endocrinologist and the person who actually discovered the existence of feline hyperT! I’m really shocked not to see this blog listed in your Resource section!

    The link below takes you to his hyperthyroidism blog page, but be sure to scroll all the way to the bottom for links to many more articles he’s written on the cause, testing, diagnosis, treatment and management of hyperT. He also has a great article about the proper diet for felines.

    Rather shockingly, as renown and as busy as this specialist is, Dr. P will actually personally answer your questions about your cat’s illness. I have consulted with him by phone and he is absolutely spectacular. This link should reside at the very top of your resource list!

    Also, at the upper right corner of this page, you will find a link to Dr. P’s other blog, which is targeted for the veterinary community. It is chock full of info on hyperT and many other endocrine related diseases and conditions. The blog is called “Insights into Veterinary Endocrinology”.

  2. Just joined this blog and love it 🙂

    My cat was diagnosed as hyper-t about 18 months ago. He was only 7 at that time.
    I switched his food to raw – we mostly use Primal and sometimes Natures variety (no rabbit).
    He was on a bpa free canned – wellness but I think the carrageenan was an issue.
    I started him on Resythro (which is now called thyroid support gold) and after 6 months his values were normal so I dropped his dose from 5 drops 2x per day to 4 drops 2x per day.
    We just got rechecked and he is still normal so I dropped his dose to 3 drops.
    It really worked for us but we did switch food and caught it early – whew 🙂
    Hope this helps others who are searching as I was frantically searching for info when he was first diagnosed.

  3. BPAs sure, but probably moreso, flame retardants (PBDEs) in our furniture, bedding and household insulation… Google it.

  4. You are right, LIz – I meant HYPERthyroid – overactive thyroid. I was really puzzled by it, too, because their diet has really been extraordinarily healthy for the last 10 or so years.

    Their raw diet consists of a mix of ground chicken, grated zucchini and grated carrot, and oat bran soaked in water. Roughly 50% chicken, 25% oat bran, and 25% vegetable. It rarely varies, although I have tried some different vegetables and starches (broccoli or corn causes gas, and they don’t seem to like sweet potato or green beans, and will not eat rice at all.) I think Sophie (the hyperthyroid cat whose digestive difficulties caused me to research the raw diet in the first place) is also allergic to eggs, so I don’t use them – and they will eat raw beef, but refuse ground turkey. Weird, hunh? I’ve never used any fish, so I’m sure it’s not that, either. I guess some people (and cats, too) just get wacky thyroids as they get older.

    Or it could be some undetermined environmental thing – oddly enough, I am also hyperthyroid.

    Thanks for your response – everyone around here thinks I am nuts for feeding my cats this way. Even my vet brother-in-law does not really approve, although he didn’t have any better suggestions when Sophie was so sick that my vet wanted to do exploratory abdominal surgery to figure out why she was having such stomach problems before I put her on the raw diet. It’s nice to hear from someone who understands!

  5. Thanks so much for this article – my 15 year old cat developed hypothyroidism, and it almost killed her.

    She stopped eating, and refused to come out from under the bed. I took her to an emergency vet rather than my own because mine was on vacation, and so this was not diagnosed until we went to my own vet for followup – they did the thyroid test and her numbers were literally off the charts. Even after the diagnosis, the prescription meds made her feel even sicker before they started to make her feel better (vet says this is normal). I had said my goodbyes to her twice before she turned the corner to survive.

    I write just to say that my cats have been on a raw diet for about 10 years – occasionally supplemented with organic dry food. Now, I have to give her some bites of wet food in which I hide her thyroid medicine, twice a day – but she is amazingly back to her normal self.

    Thanks for this blog! I will be following you from now on!

    1. Hi Gin, thanks sharing your story about your cat. I’m so glad she is doing well now. You said “hypothyroidism” – did you mean “hyperthyroidism”?

      If you do mean “hyper-“, I wonder – you’ve been feeding your cats so well! Clearly BPA in cans was not a cause in this case…do you think unsuspected PBDEs in large fish could have played a role?