Vitamin B1 Deficiency in Cats

An essential nutrient in the liver, heart and kidneys, vitamin B1 or thiamine, assists in the process of metabolizing energy, throughout your cat’s body. Vitamin B1 does this by interacting with other B vitamins to help break down and convert the food your cat eats into usable energy. Without proper levels of vitamin B1, your cat can quickly become lethargic and develop a range of alarming and dangerous symptoms. 

Inadequate vitamin B1, or thiamine deficiency, in cats is associated with vascular and neurological damage and can be a potentially life-threatening condition.  

Since it is an essential nutrient which allows cats to break down, process, and absorb energy from carbohydrates, the first symptoms you’ll notice in vitamin B1 deficiency will involve eating and energy issues. Energy from carbohydrates is also an important fuel source for brain function and various neurological processes and the symptoms of vitamin B1 or thiamine deficiency in these areas will progress in severity as the syndrome continues.

Below are the main symptoms you should look out for in vitamin B1 deficiency:

• Lethargy: As your cat is unable to process energy, their activity levels will fall drastically.
• Drooling: Drooling or increased mouth moisture can be an indication of early neurological symptoms and/or vomiting.
• Vomiting: As your cat is unable to process and break down their food efficiently, vomiting may ensue.  
• Anorexia: Similar to vomiting, as you cat becomes unable to process their food they may develop lack of appetite.
• Neck Flexion: Neck flexion, of a bending or bowing of the head downwards towards the chest, is a neurological symptom that may develop in your cat as vitamin B1 deficiency progresses.
• Seizures: Another common neurological symptom that develops from the brain’s lack of appropriate fuel sources.

Vitamin B1 is an important nutrient in a healthy cat’s daily diet and the AVMA has specified a recommended daily dose. To illustrate the importance of B1 for our feline companions, cats require nearly 3 times the amount of vitamin B1 in their diet than dogs. 

• Lack of Vitamin B1 in Commercial Cat Foods: Most modern commercial cat food diets include adequate amounts of vitamin B1, however there have been occasional recalls of name brand cat foods over the years due to an improper vitamin B1 ratio. 
• Raw Cat Food Diets: The biggest problem areas for vitamin B1 deficiency may occur in raw, or homemade cat food diets. Often times owners will inadvertently not provide the correct levels of nutrients or feed human foods that aren’t appropriate for their cat’s diet. 
• Thiaminase and Vitamin B1 Deficiency: Some types of raw fish also have a naturally occurring enzyme called thiaminase which can break down thiamine/vitamin B1. 

Vitamin B1 deficiency in your cat can be a complex diagnosis and requires the care and attention of a qualified veterinarian. Your vet will ask for a complete list of symptoms and timelines. You can assist your veterinarian in their diagnosis of vitamin B1 deficiency in your cat by documenting your pet’s behavior including eating and drinking habits, duration of neurological episodes such as seizures, and total length of time since onset of the initial indications that your cat may be sick.

A qualified veterinarian will review the clinical presentation, or physical symptoms, and will also run certain baseline tests. This can include a complete blood count or CBC, a biochemical profile and a urinalysis, all of which will be helpful in determining the levels of vitamin B1 present. In advanced cases, the vet may also order imaging which may show lesions in the brain area. 

The good news is that while vitamin B1 deficiency in your cat can be a life-threatening condition, it is also one that is easily treated. A veterinarian will initially treat the underlying deficiency by giving an injection of thiamine directly under the skin. Thiamine is water soluble and excess thiamine is easily excreted through your cat’s urinary functions, so this initial correction is safe and effective. 

The next step your vet will take is management of the cause of the deficiency. This can be as simple as a change in diet; eliminating or adding certain types of food. A vet may also prescribe supplements for your cat such as a prescription multivitamin, in order to correct any nutritional deficiencies.

After treatment, your cat should begin to recover from vitamin B1 deficiency rapidly. Thiamine/vitamin B1 is rapidly absorbed by your feline and the body immediately begins utilizing the nutrient for appropriate energy processes. Immediate relief of symptoms can be seen as soon as a few hours after initial treatment, with full recovery in as little as 48 hours. In some cases, your vet may need to administer several vitamin B1 shots over the course of a week or more. With appropriate diagnosis and management your cat will be back to its normal, healthy self quickly and completely.