This Deficiency Can Prove Fatal if Not Addressed Quickly

canned cat food

Story at-a-glance -

  • Thiamine (vitamin B1) levels in canned pet food are highly unpredictable due to high heat processing methods and extended storage times
  • Cats need about three times the amount of dietary thiamine that dogs do, placing them at a much higher risk for developing a deficiency
  • Thiamine deficiencies must be caught quickly to be successfully treated; unfortunately, symptoms often don’t appear for weeks
  • Another problem with canned pet food is the presence of bisphenol-A; dogs switched to canned food tripled their BPA blood levels in just two weeks and also underwent metabolic changes and alterations to gut bacteria
  • If you're concerned about thiamine levels, bisphenol-A and other problems with canned pet food, consider transitioning your pet to a nutritionally balanced, fresh food diet

By Dr. Karen Shaw Becker

Thiamine, or vitamin B1, is a water-soluble vitamin absorbed from the diet through the small intestine. The body doesn’t store thiamine, so it’s easy to develop a deficiency if there isn’t enough of this nutrient in the daily diet. And since cats require about three times the amount of dietary thiamine that dogs do, kitties are at significantly higher risk for developing a deficiency.

Thiamine helps support healthy function­ing of nerves, muscle cells and the brain in animals, including humans. A thiamine shortage means the body can’t effi­ciently convert carbohydrates into energy. Organs that use a lot of energy (like the brain) can be severely compromised by a thiamine deficiency. A lack of thiamine can also lead to a buildup of lactate, resulting in acidosis.

Thiamine Levels in Canned Cat Food Are Notoriously Unpredictable

Unlike many other nutrients in processed pet food, thiamine levels present some unique challenges, with the result that thiamine-deficient pet foods are an ongo­ing issue. This is especially true for canned cat diets, in particular those labeled for intermittent and supplemental feeding only (unbalanced diets).

A report published last year by pet food researchers at Kansas State University concluded that the size and shape of cat food containers have no bearing on thiamine loss during manufacturing.1 The main culprits seem to be time and temperature, and processed pet foods are manufactured at extremely high temperatures and are designed to sit for months on a shelf or in a freezer.

Thiamine naturally present in food can also be destroyed by exposure to high levels of glutamate found in vegetable protein. Cat food manufacturers supple­ment their formulas to compen­sate for the loss of thiamine during processing, however, it isn’t a perfect science. It’s common for manufacturers to issue recalls for low levels of thiamine. One fairly recent example is the J.M. Smucker Company voluntary recall of certain lots of 9Lives, EverPet and Special Kitty canned cat food.2

Other Ways Your Pet Can Become Thiamine-Deficient

Canned diets are the type most commonly deficient in thiamine because of the way they are processed, but dry foods exposed to air, humidity or heat can also lose thiamine content. An unbalanced raw or homemade diet can also be thiamine-deficient. A thiamine deficiency can develop from feeding pets large amounts of raw fish containing the enzyme thiaminase, which destroys thiamine, and also from feeding pet food containing sulfites, which inactivate thiamine.

Pets fed high-carbohydrate foods may experience deficiencies because their bodies have a greater demand for thiamine to metabolize all those carbs. In addition, animals with intestinal disease that interferes with nutrient absorption may be thiamine-deficient, as well as pets taking certain medications like diuretics.

Signs Your Pet Might Be Thiamine-Deficient

Progressive symptoms of a thiamine deficiency can take weeks to develop, but initial signs of general gastrointestinal (GI) upset including vomiting, excessive salivation, loss of appetite and weight loss often occur within a week after an animal begins eating a diet severely lacking in thiamine. If the deficiency remains untreated, neurological signs will follow. These can include:

Dilated pupils

Ventriflexion (bending downward) or curling the neck backward

Loss of coordination

Arching the head, neck and spine

Head tilt




Abnormal gait


Typically, a pet must be thiamine-deficient for around a month before the terminal stage is reached. Once an animal has entered this stage, he or she will die within a few days if the deficiency is not immediately reversed. Diagnosing thiamine deficiency in a dog or cat can be somewhat complicated. Thiamine exists in several forms in an animal's body, and measuring the concentrations can be a challenge.

Two tests are typically used to evaluate a pet's thiamine status: one is the erythrocyte transketolase activity assay, and the other is high-pressure liquid chromatography. Most often, however, thiamine deficiency is diagnosed based on the animal's symptoms, dietary history and response to treatment.

How to Ensure Your Dog or Cat Is Getting Enough Thiamine

When the cause of a pet's illness is suspected to be thiamine deficiency, it's important to initiate treatment immediately, even without a confirmed diagnosis. Treating a thiamine deficiency involves feeding a nutritionally balanced, species-appropriate diet that has been analyzed to verify it meets thiamine requirements.

It’s also important to limit or eliminate raw fish from the diet. If you want to feed your pet fish occasionally, I recommend sardines packed in water or wild-caught, gently cooked salmon. Often thiamine is given by injection for three to five days, followed by oral supplementation for two to four weeks.

If you're feeding a variety of high-quality, human-grade commercial pet foods (preferably a balanced raw diet), you may not need to add more thiamine, especially if you buy small packages and use the food up in 60 days or less. If you're feeding a lesser-quality brand or are preparing your pet's meals at home, a vitamin B1 supplement may be advisable.

Discuss your pet’s thiamine intake with your holistic veterinarian or pet nutritionist to make sure you’re providing optimal amounts in the diet you offer your pet.

More Bad News About Canned Pet Food

A 2017 study conducted by researchers at the University of Missouri concluded that even short-term feeding of canned dog food results in a significant increase of BPA (bisphenol-A) in dogs.3 BPA is able to imitate the body's hormones, especially estrogen, in ways that are damaging to the health of both humans and animals. In humans, exposure to BPA has been linked to:4

  • Reproductive disorders and breast cancer in women and impotence in men
  • Heart disease, diabetes and liver-enzyme abnormalities
  • Problems in brain function, memory and learning
  • Reduced effectiveness of chemotherapy treatment
  • Asthma

The researchers wanted to determine if short-term feeding of commercial canned food could alter blood concentrations of BPA in dogs. They also looked at whether BPA exposure from the canned food affected the dogs' gut bacteria or caused metabolic changes.

The two-week study involved 14 healthy pet dogs. Blood and stool samples (used for microbiome assessments) were taken before and after the two-week period, during which the dogs were fed one of two widely available canned dog foods, one of which claimed to be BPA-free. The cans and the food in them were also analyzed for BPA levels.

After Just 2 Weeks, the Dogs’ BPA Levels TRIPLED

According to study author Dr. Cheryl Rosenfeld of the University of Missouri's College of Veterinary Medicine:

"The dogs in the study did have minimal circulating BPA in their blood when it was drawn for the baseline. However, BPA increased nearly [threefold] after being on the either of the two canned diets for two weeks.

We also found that increased serum BPA concentrations were correlated with gut microbiome and metabolic changes in the dogs analyzed. Increased BPA may also reduce one bacterium that has the ability to metabolize BPA and related environmental chemicals."5

Translation: The dogs had low levels of BPA in their blood at the start of the study, but those levels tripled during the two-week period when they were eating the canned foods — including the one that claimed to be BPA-free. Upon analysis, that food did indeed contain BPA.

In addition to the increased levels of BPA in their blood, the dogs also underwent metabolic changes and alterations in their gut bacteria. The researchers theo­rized the BPA might have depleted a bacteria strain that helps metabolize BPA and related environmental chemicals.

Worried About Your Pet’s Canned Food?

If you're concerned about thiamine levels, bisphenol-A and other problems with canned pet food, my suggestion is to consider transitioning your dog or cat to a nutritionally balanced, fresh food diet, either homemade or commercially available.

Whatever you do, please don’t go from canned to kibble. Kibble is biologically inappropriate for cats and dogs. In addition, the food is heated to very high temperatures, which denatures proteins and decreases nutrient value, and also potentially introduces carcinogens into your pet's body on a daily basis.

If you're feeding your pet a processed diet, also consider an intermittent detoxification protocol. I also recommend using stainless steel, glass, or ceramic food and water bowls instead of bowls made of plastic.