Thiamine (vitamin B1) is essential for carbohydrate metabolism and nerve function in your cat. Cats are particularly vulnerable to thiamine deficiency compared to many other animals because they have higher metabolic requirements for this vitamin and several common dietary factors can destroy it. Raw freshwater fish contains thiaminase, an enzyme that breaks down thiamine, and excessive heat during food processing can also deplete it. Thiamine deficiency in cats causes severe and rapidly progressive neurological damage that can become fatal within days if not treated.
A small serving of cooked chicken (about 30g) provides roughly 0.02–0.03mg of thiamine — your adult cat needs approximately 0.3–1.0mg per day, which commercial cat foods are formulated to provide. Never feed your cat raw fish regularly, as the thiaminase enzyme will destroy thiamine and can cause life-threatening deficiency within weeks.
0.0% of daily nutrient intake
Vitamin B1 (Thiamine) makes up 0.0% of your cat's total daily nutritional requirements by weight. That's a tiny amount — but it matters.
Neurological signs develop rapidly and include loss of appetite, vomiting, a wobbly or uncoordinated gait (ataxia), head tilting, circling, seizures, ventroflexion of the neck (the cat's head drops toward its chest — a hallmark sign), and in advanced cases, coma and death. Thiamine deficiency is a medical emergency.
Thiamine is water-soluble and excess is readily excreted in urine, so toxicity from dietary sources is essentially impossible. There is no practical upper limit concern for thiamine in cats.
| Life Stage | Size | Min | Max | Unit | Notes |
|---|---|---|---|---|---|
| Adult | — | 0.28 | 1 | mg | Cats are highly sensitive to thiamine deficiency. Raw fish containing thiaminase is a common cause of fatal thiamine depletion in cats. |
| Juvenile | — | 0.3 | 1.2 | mg | Growing kittens need thiamine for nervous system development. Deficiency causes rapid neurological decline. |
Source: NRC 2006, AAFCO 2024
B vitamins work synergistically in energy metabolism and nervous system function. Thiamine and B6 in particular both support nerve health and amino acid processing, and adequate levels of both are needed for optimal function.
What this means: Meat-based diets naturally provide a full complement of B vitamins, so individual B vitamin deficiencies are uncommon in cats eating commercial food. The exception is thiamine, which can be destroyed by raw fish (thiaminase) or excessive heat during food processing. If your cat shows neurological signs, check thiamine status first.
