🧠 Thiamine (Vitamin B₁) Deficiency in Cats: Vet Guide – 2025 🐱

Hello cat families! 😺 I’m Dr Duncan Houston BVSc, and this in-depth 2025 guide explores thiamine deficiency in cats—a rare but serious nutritional problem that can lead to neurological symptoms, appetite loss, and vomiting. We'll cover causes, clinical signs, diagnosis, treatment, recovery, and when you should contact Ask A Vet. Let’s give your cat the care it deserves! ❤️

1️⃣ Understanding Thiamine & Its Role

Thiamine, also known as vitamin B₁, is vital for energy production in the brain, nerves, heart, and muscles. Cats cannot store surplus thiamine, so they're particularly prone to deficiency from poor diets or vitamin destruction. It is heat- and acid-sensitive, which means that even homemade diets may be deficient unless carefully balanced.

2️⃣ Why It Happens in Cats

• Poor-quality or imbalanced homemade/raw diets—cooking fish/food incorrectly can destroy thiamine.
• Feeding raw fish like carp or herring—these contain thiaminase enzymes that break down thiamine.
• Prolonged vomiting or diarrhea—leads to nutrient losses.
• Diseases or drugs that impair absorption or increase demand.
• Cat food with expired/mishandled thiamine supplements—even commercial food may lack adequate B₁.

3️⃣ Who’s Most at Risk

• Kittens and young cats on homemade or raw meat diets without proper supplementation.
• Any cat fed raw fish often.
• Cats with gastrointestinal illness or prolonged inappetence.

4️⃣ Recognizing the Signs ⚠️

Thiamine deficiency can progress rapidly, causing early and late clinical signs:

• Early signs (often within 1–2 weeks):
  • Loss of appetite, vomiting, weight loss
  • Stress intolerance or lethargy
• Neurological signs (if untreated):
  • Restlessness, circling, pacing
  • Head tilt, ataxia, stumbling, wide-based gait
  • Seizures, catatonia, blindness, tremors
• Ophthalmic signs: impaired pupillary light response, dilated pupils
• Severe cases: coma or death if no treatment

The onset may be dramatic after a meal, or gradual if dietary imbalance persists.

5️⃣ Diagnosis Steps 🔍

A vet will:

• Take a complete diet history—fresh/raw versus kibble, frequency, supplement use.
• Perform a physical and neurological exam.
• Check routine bloodwork—often normal, but useful to rule out other causes.
• Perform MRI/CT in severe neurologic cases to rule out structural brain disease.
• Observe rapid clinical improvement after thiamine supplementation as a diagnostic clue.

6️⃣ Treatment Plan 💊

🔧 Immediate Intervention

• Administer vitamin B₁ via injection (IM or IV) for 3–5 days.
• Transition to oral thiamine supplementation thereafter.
• Correct fluid/electrolyte imbalances.

🔄 Ongoing Supportive Care

• Introduce a complete balanced diet, ideally veterinary-formulated.
• Administer anti-emetics to stop vomiting.
• Offer assisted feeding for hyporexic cats.
• Provide physical therapy as needed if neurological signs present.
• Encourage a calm environment—reduce stress and stimulation.

7️⃣ Prognosis & Recovery 🌈

• Early treatment: symptoms often improve within 24–72 hours.
• Moderate cases: normal feeding resumes in days, neurologic signs resolve in 1–3 weeks.
• Severe cases: seizures may require long-term management, full recovery is possible.
• Delayed treatment: risk of permanent deficits or fatality is high.

8️⃣ Prevention & Owner Tips 🛡️

• Feed high-quality commercial or veterinary-formulated diets with B₁ supplementation.
• If feeding homemade or raw, include a vet-approved B‑complex vitamin.
• Avoid raw fish that may contain thiaminase.
• Monitor for GI upset; treat vomiting promptly.
• Store food properly—heat/damage may degrade thiamine.
• Schedule regular wellness exams and discuss diet in detail.

9️⃣ When to Contact Ask A Vet 📲

Use the app or contact your vet immediately if your cat shows:

• Sudden loss of appetite, vomiting, or weakness.
• Any neurologic signs—circling, head tilt, twitching, stumbling.
• Seizures, collapse, or blindness.

Ask A Vet can advise you right away on assessing neuro status, giving emergency vitamin support, controlling vomiting, and choosing in-clinic or hospital referral. Expert care starts within minutes! 🐾❤️

🔟 Quick Reference Table 📊

💡 Dr Duncan’s Final Thoughts

Thiamine deficiency may be rare, but its effects can be profound. Fortunately, with quick care and supplementation, most cats make a full recovery. When in doubt—if your cat is vomiting or showing neuro signs—reach out to Ask A Vet or your veterinarian without delay. Prevention and early treatment are your greatest allies. 😊🐾

Dr Duncan Houston BVSc — Your feline nutrition and neurology partner. Visit AskAVet.com and download the Ask A Vet app for immediate, compassionate support anytime. 📱