Thiamine (also known as Vitamin B1) is a water soluble vitamin. Thiamine plays an important role in numerous body functions including helping the body metabolise carbohydrates into energy &  maintaining a healthy heart & nervous system. Thiamine is found in whole-grains, some fruits & vegetables, meat, liver, bread, brewers yeast, legumes & milk.

Thiamine deficiency is quite rare in cats, and is most typically seen when a cat has been fed a diet containing large amounts of raw fish.

Causes of thiamine deficiency include;

• When a cat  is fed a diet containing large amounts of raw fish. Raw fish contains the enzyme thiaminase  which destroys thiamine. Cooking destroys thiaminase, thus protecting thiamine.
• Sulphur Dioxide (220) is a preservative found in some brands of 'pet mince'. Sulphur dioxide inactivates thiamine. [1] Pet food manufacturers therefore must carefully monitor their products to ensure they contain adequate levels of thiamine for cats.
• Thiamine is soluble in water & therefore can be lost if cooked in water. If you are to cook your cat's food in water, then use as little as possible.
• High heats can also destroy thiamine. Once again, pet food manufacturers must carefully monitor their products to ensure they contain adequate levels of thiamine to compensate for the loss during the cooking process.
• Cheap/generic brands of cat food may not monitor these levels as carefully as they should, therefore it is always wise to choose your pet foods carefully & feed a varied diet.

Thiamine is not stored in the body, and therefore is quickly depleted if the cat is fed an inadequate diet or goes without food for any period of time. It is therefore important to ensure the diet contains adequate amounts of this vitamin.

What are the symptoms of thiamine deficiency in cats?

• Anorexia
• Salivation
• Dilated pupils
• Ataxia (loss of coordination)
• Cervical ventroflexion (necks flexed/rigid, which causes an inability to raise the head, the chin rests near the chest)
• Seizures
• Loss of righting reflexes
• Bradycardia (slow heartbeat)
• Aggression

How is thiamine deficiency in cats diagnosed?

Your veterinarian will perform a complete physical examination & obtain a history from you, including information on your cat's diet. The most common sign of thiamine deficiency is cervical ventroflexion.

How is thiamine deficiency treated?

• Putting the cat on a nutritionally balanced diet.
• Cutting down or eliminating raw fish from the cat's diet.
• Administering thiamine injections.

References:

[1] Australian Veterinary Association warning over preservatives in pet food.