Vitamin B1 (Thiamine) Deficiency in Cats


PetMD Editorial

Published Oct. 9, 2012

Thiamine Deficiency in Cats

Thiamine, also known as vitamin B1, is a water-soluble vitamin necessary for normal carbohydrate metabolism in cats. Thiamine deficiency results in serious symptoms, many of which are neurological in origin.

Symptoms and Types

 Neurological signs are frequently seen with thiamine deficiency and include:

  • Ventriflexion (bending towards the floor) or curling of the neck
  • Incoordination
  • Abnormal or spastic gait
  • Circling
  • Falling
  • Head tilt
  • Dilated pupils
  • Opisthotonos (backward arching of the head, neck, and spine)
  • Stupor
  • Seizures

Neurological symptoms may be preceded by gastrointestinal symptoms such as vomiting. Excess salivation, depressed appetite, and weight loss can also be seen before neurological symptoms present.


There are many potential causes of thiamine deficiency. These include:

  • Prolonged lack of appetite
  • Diseases that cause malassimilation or malabsorption of nutrients
  • Extensive surgical resection of jejunum and ileum
  • Diuresis (excessive urination)
  • Feeding an all meat diet
  • Feeding meat based diet that has been preserved with sulfur dioxide
  • Consumption of diet which has destroyed vitamin B1 during food processing. Some food recalls have been related to thiamine destruction which occurred during processing and caused inadequate thiamine levels in food. Food lacking adequate quantities of thiamine may in turn cause a thiamine deficiency for cats eating the food.
  • Destruction of B1 by thiaminase present in some bacteria and in certain types of raw fish (cod, catfish, carp, herring, etc).


Your veterinarian will base the diagnosis based on the presence of clinical signs associated with thiamine deficiency, a history of ingestion of food deficient in thiamine, or other factors that may lead to thiamine deficiency, and response to treatment. Thiamine levels in blood can also be measured to confirm thiamine deficiency.


Thiamine can be injected or given orally. Providing adequate quantities of thiamine is the treatment of choice.


Feed a high quality, well balanced diet.

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