Get

In Your Inbox

Catster is reader-supported. When you buy via links on our site, we may earn an affiliate commission at no cost to you. Learn more.

Thiamine Deficiency in Cats: 14 Signs to Look For (Vet Answer)

tired sick cat lying on bed

Thiamine deficiency, or vitamin B1 deficiency, is a clinical syndrome associated with vascular lesions and nerve damage caused by an insufficient concentration of this vitamin in a cat’s body. This deficit is due to insufficient intake of vitamin B1 (part of the B complex group) to the body’s requirements.

It’s predominant in cats that consume large amounts of raw fish because these contain a compound that destroys vitamin B1. Thiamine deficiency can also occur in cats that consume unsupplemented commercial food, cooked food, or certain raw meats. Additionally, gastrointestinal and liver diseases can lead to thiamine deficiency.

Vitamin B1 deficiency is quite rare in cats but can be life-threatening if the clinical signs are not recognized by their owners in time. For this reason, you should know the clinical signs of thiamine deficiencies if your cat has a poor diet or eats large amounts of raw fish.

divider cats oct 2024

What Is Thiamine Deficiency in Cats?

Thiamine, or vitamin B1, is a water-soluble vitamin (i.e., it dissolves in water) that is part of the B complex. It’s essential for your cat’s body and has the following roles:

  • Plays a key role in the metabolism of carbohydrates
  • The production of certain nucleotides, which are the building blocks of RNA & DNA
  • Production of other coenzymes necessary for normal metabolism
  • It plays an essential role in maintaining a healthy nervous system

Thiamine may also have other functions that are not currently known, as it’s widely involved in a plethora of normal metabolic processes all around your pet’s body, in just about every body system. Cats cannot synthesize thiamine, so their diet must contain this vitamin.  When the food that they consume is low in vitamin B1, thiamine deficiency occurs.

What Are the Causes of Thiamine Deficiency in Cats?

There are several mechanisms for a thiamine deficiency.

How Thiamine Deficiency Occurs in Cats
  • The cat’s diet has specific enzymes that can break down thiamine (a risk associated with raw seafood).
  • The commercial food is not supplemented with enough thiamine to meet your cat’s needs.
  • Cats that are fed dog food can develop a deficiency, as they require up to four times more thiamine than dogs do.
  • Cats fed a species-inappropriate diet (such as a vegetarian or vegan diet) may develop deficiencies due to the consumption of inappropriate foods.
  • Cats fed preserved meats might develop thiamine deficiency, due to some preservatives (such as sulfur dioxide) being able to destroy thiamine.
  • Poor absorption of thiamine due to underlying health issues or pathologies (particularly those involving the liver).
  • Excessive loss of thiamine due to kidney issues or due to the consumption of diuretics.

divider cats oct 2024

The 14 Signs to Look For in Thiamine Deficiency

Generally speaking, thiamine deficiency has three phases or stages: an induction stage, a critical stage, and a terminal stage. The signs during each stage as are follows:

The Induction Stage

The induction stage often occurs when a cat’s diet has been deficient in thiamine for a period of around 2 weeks.

Signs of the Induction Stage:
  • Reduction in food intake (hyporexia)
  • Refusal to eat (anorexia)
  • Vomiting
  • Lethargy
  • Weight loss might be noticed

If your cat doesn’t receive veterinary care during the induction stage, they will proceed to the critical stage.

tired or sick cat lying on bed
Image Credit: Prystai, Shutterstock

The Critical Stage

The critical stage occurs if the induction stage is ignored and your cat continues to deteriorate.

Signs of the Critical Stage:
  • Bending the neck in a downward position (cervical ventroflexion)
  • Dilated, fixed pupils
  • Muscle weakness
  • Tremors
  • Ataxia (unsteady gait/wobbly walk)
  • Paralysis of the eye muscles
  • Seizures (in extreme cases)

Neurological signs generally have a rapid onset and precede vomiting. In some cases, tetraparesis with developed rigidity may also occur. This stage will eventually progress to the terminal stage.

The Terminal Stage

The terminal stage usually occurs if your cat has a thiamine deficiency for around a month or so, with no intervention or treatment.

Signs of the Terminal Stage:
  • Severe deficiencies of the signs associated with the critical stage
  • Eventual collapse and death

The terminal stage is considered fatal within just a few days. Most cats will perish unless veterinary treatment begins immediately.

divider cats oct 2024

Thiamine Deficiency Diagnosis

The presumptive diagnosis is usually based on clinical signs and history. The most common way a diagnosis is usually made by vets is by assessing the response that deficient cats have when supplementing their diet with thiamine.

Other tests include a biochemical blood profile, a complete blood count, and urine analysis; however, these tests are usually somewhat inconclusive. A set of chest and abdominal X-rays can also be recommended, as it is part of the investigation (especially when vets want to rule out other health conditions with similar signs). In rare instances, an MRI might also be warranted.

If you are concerned or have questions about your cat’s health, you can also speak to a vet from the comfort of your own home to help make a plan. They can determine when an in-clinic vet visit should be made.

If you need to speak with a vet but can't get to one, head over to PangoVet. It's an online service where you can talk to a vet online and get the advice you need for your pet — all at an affordable price!

PangoVet_Mention-in-Content for PangoVet2 save money

Thiamine Deficiency Treatment

Treatment Includes:
  • Supplementing your cat with thiamine – This can be done either orally (with assisted feeding) or via injections, depending on the severity of your cat’s condition.
  • Assessing the underlying cause of the thiamine deficiency – A veterinarian may opt for a long-term dietary change for your cat and may make adjustments to your pet’s diet, such as limiting or suspending your cat’s raw fish diet.

Depending on your cat’s condition, they may be hospitalized for a period of time until they are stabilized and on the road to recovery. A veterinarian may opt for a feeding tube for your cat for a period of time and also prescribe them a critical care or liquid diet for a period of time.

If your cat’s deficiency was caused by issues such as those involving the liver or kidneys, the veterinarian would prescribe additional medications and therapies to address those ailments.

Portrait of a beautiful scottish tabby cat
Image Credit: Inna Novogel, Shutterstock

Thiamine Deficiency Prognosis

The prognosis of your cat, or the odds of their recovery, depend on the severity of their deficiency at the time of presentation to the veterinarian. Cats in the induction or critical phase generally have a more favorable prognosis when compared to cats that are presented in the terminal stage of the condition.

divider cats oct 2024

Conclusion

Thiamine deficiency can be life-threatening for cats if it is not diagnosed and treated in time. The causes of this deficiency are various underlying ailments or nutritional insufficiencies that lead to a low thiamine intake. Common clinical signs include lack of appetite, vomiting, and nervous signs, such as twitching, incoordination, and dilated pupils. If you suspect that your cat has a thiamine deficiency, you should promptly contact a veterinarian, as an earlier diagnosis offers a better chance of recovery.


Featured Image Credit: Natata, Shutterstock

Want content like this delivered to you?

Sign Up For Our Newsletter

News, insights, expert advice, and everything cat

* By submitting, you agree to our Terms & Conditions and Privacy & Cookies Policy.




How useful was this post?

Click on a star to rate (you can leave written feedback after clicking submit)

Help us improve Catster for pet parents!

Your feedback really matters.

What did you like about this post? Also how can we improve it?

Join the conversation

Leave a Reply

You’re very welcome to leave a comment or question. Please know that all comments must meet our community guidelines, and your email address will NOT be published. Let’s have a positive and constructive conversation.


Talk With A Vet Online

Peace of mind,
anywhere, anytime

Affordable vet advice

9 Best Litter Boxes for Ragdoll Cats in 2026 – Reviews & Top Picks

Ragdolls are a big, beautiful, lovable breed of cat that has acquired fanciers across the world. Ragdolls can get quite large, though, which...

Why Is My Cat So Clingy? 5 Vet Reviewed Reasons for This Behavior

Cats are often praised for being incredibly low-maintenance pets. Besides finding food, cats practically do everything on their own, including bathing, going to...

How Old Do You Need to Be to Adopt a Cat? Vet-Reviewed Guidelines & Info

Adopting a cat is a process that involves planning and preparation, as well as the signing of documents. Because of this, most shelters...

Siberian Cat Breed: Info, Pictures, Temperament & Traits

The Siberian cat is an anomaly. After all, the ancestor of our pets is the African Wild Cat (Felis silvestris lybica), which isn’t...

More related

Abyssinian Siamese Mix: Info, Pictures, Care Guide & Temperament

Mixed-breed cats can have huge personalities and offer more unique traits than most purebreds, and it’s a big reason why so many people...

250 Cartoon Cat Names: Ideas for Charismatic & Comical Kitties

Cats have lived alongside humans for thousands of years and have always been a subject of interest to artists and creatives. From ancient...

How to Live with Multiple Cats: 9 Vet-Approved Tips

A cat can bring joy and happiness to a home. So, it stands to reason that having multiple cats multiplies this joy. But,...

6 Free DIY Cat Gate & Barrier Plans You Can Make Today

Every cat owner knows that cats are curious and love to explore, but you want to protect your cat, too. Letting your cat...

Keep reading

Can Cats Control Their Tails? Vet-Verified Positions & Movement Explained

Cats use their tails to communicate to the world through body language. You can tell a lot about a cat’s disposition by what their tail is doing. With that being said, cats have full control of their tails. The tail...

tail of a cat on vintage background

Caring For a 1-Year-Old Cat: Vet-Reviewed Health & Wellness Tips

Now that your kitten has hit their 1-year milestone, you’re likely wondering how things will change, since at 12 months, most cats are officially adult cats. It’s important to keep up with your cat’s different life stages, as this will...

bengal cat walking

6 Homemade Cat Food Recipes for Senior Cats (With Pictures)

We all know that a nutritionally balanced diet made up of high quality ingredients is vital to a long and healthy life. But with so many types of senior cat food on the market, how can you be sure that...

Homemade Cat Food Recipes for Senior Cats

Why Do Cats Scoot? 5 Vet Reviewed Reasons & What to Do

If you live with a feline, you may have seen your buddy engage in a few less than elegant activities, including the dreaded scoot—where your cat’s dragging their butt on the floor leaving something stinky behind. Cleaning up the results...

cat-sitting-scooting

Why Does My Cat Cry When I Leave? Vet-Verified Reasons & Solutions

While cats are often considered not to be terribly interested in people, they’re actually sensitive, loving creatures that become deeply attached to those they share their lives with. Companion cats develop bonds with their people that resemble those formed between...

Cat meowing

How to Stop Cats From Getting Pregnant Naturally: Vet Approved Advice

Preventing a cat from getting pregnant is most commonly accomplished through spaying and neutering. But there might be times when a cat owner doesn’t want such a permanent solution and would rather investigate other options. It’s even better if it...

cat-having-a-vaccine

9 Best Cat Foods for Irritable Bowel Syndrome (IBS) in 2026: Reviews & Top Picks

Occasional diarrhea is common in housecats. However, if your cat keeps displaying symptoms of digestive distress, it should be cause for concern. IBS can result from several causes that include stress, neurological issues, and parasites. Dietary intolerances and sensitivities in...

cat eating food from the bowl

Nulo Cat Food Review of 2026: Recalls, Pros & Cons

Review Summary Nulo is a California company that makes a wide range of cat and dog foods. It started with a man trying to take better care of his dog and blossomed into a full-grown pet care business, with high-quality...

Nulo Freestyle Cat Food Review

Love Cats? So Do We! Join the Catster Community

Stay informed with expert pet care insights delivered straight to your inbox! Discover professional guidance on animal behavior, feeding tips, trusted product picks, and much more.




Sign up for the Catster Email Newsletter

Stay informed with expert pet care insights delivered straight to your inbox! Discover professional guidance on animal behavior, feeding tips, trusted product picks, and much more.