Thiamine deficiency
Symptoms, at-risk groups, and clinical context for thiamine deficiency. Sourced from NIH Office of Dietary Supplements and StatPearls.
Thiamine (vitamin B1) deficiency is rare in the US general population due to grain fortification, but it remains common in people with chronic alcohol use, certain GI conditions, and after bariatric surgery. Severe deficiency causes beriberi or Wernicke-Korsakoff syndrome — both can be life-threatening and may cause permanent neurological damage if not treated promptly.
Common symptoms
- Fatigue and weakness
- Loss of appetite, weight loss
- Confusion or memory problems
- Tingling or numbness in hands and feet (peripheral neuropathy)
- Muscle weakness, especially in legs
- Heart palpitations or shortness of breath (wet beriberi affects the heart)
- Difficulty walking, balance problems (ataxia)
- Eye movement abnormalities (ophthalmoplegia — Wernicke's)
- Severe disorientation or confusion (Wernicke encephalopathy — medical emergency)
At-risk groups
- People with alcohol use disorder (highest risk for Wernicke-Korsakoff syndrome)
- People who've had bariatric surgery (especially gastric bypass)
- People with severe or persistent vomiting (hyperemesis gravidarum, post-surgical)
- People on long-term diuretic therapy (furosemide)
- People with chronic kidney disease, especially on dialysis
- Older adults with poor diets
- People with chronic GI conditions causing malabsorption (Crohn's, celiac)
- Populations relying on polished white rice as a staple
When to see a doctor: Sudden confusion, eye movement abnormalities, or balance problems — especially in someone with alcohol use disorder, recent bariatric surgery, or severe vomiting — should be treated as a MEDICAL EMERGENCY. Wernicke encephalopathy requires immediate IV thiamine; oral supplementation is too slow.
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Related deficiencies
Nutrients with overlapping symptoms — useful when investigating an unclear clinical picture.