Vitamin B1 (thiamine) helps convert carbohydrates into energy, supporting metabolism and cellular energy production. It’s essential for healthy nerve function, muscle contraction and normal heart function, and contributes to cognitive performance and mood. Adequate intake prevents deficiency disorders like beriberi and Wernicke–Korsakoff syndrome, and supports appetite and digestion. It’s water‑soluble and must be obtained from diet or supplements when needed.

Foods rich in vitamin B1 (thiamine) include whole grains—brown rice, whole wheat and oats—legumes such as lentils and beans, and lean pork. Nuts and seeds (especially sunflower seeds), green peas, and fortified breakfast cereals are also good sources. Including a variety of these foods regularly helps maintain adequate thiamine levels for energy metabolism and nervous system function.

Low vitamin B1 (thiamine) causes fatigue, poor appetite, weight loss, irritability and impaired concentration. Progressive deficiency leads to peripheral neuropathy (numbness, tingling, muscle weakness), muscle wasting, and cognitive decline. Severe deficiency produces beriberi — dry (nerve damage) or wet (heart failure, swelling, breathlessness) — and can trigger Wernicke’s encephalopathy (confusion, eye movement problems, ataxia), a medical emergency.

Vitamin B1 (thiamine) and B12 (cobalamin) are different vitamins with distinct roles. Thiamine helps convert food into energy and supports nerve function; deficiency causes beriberi and Wernicke–Korsakoff. Cobalamin is crucial for red blood cell production, DNA synthesis, and neurological health; deficiency leads to megaloblastic anemia and neuropathy and requires intrinsic factor for absorption. Food sources and supplements differ.

Yes — daily thiamine (vitamin B1) is generally safe when taken at recommended amounts. Adults typically need about 1.1–1.2 mg daily, with slightly higher needs in pregnancy or lactation. B1 is water‑soluble so excess is usually excreted; adverse effects are uncommon. Consult a healthcare professional before high‑dose supplements or if you have kidney disease, alcohol use disorder, malabsorption, or take interacting medications.

Riboflavin (vitamin B2) deficiency causes sore throat, swollen red or magenta tongue (glossitis), cracks and painful lesions at mouth corners (angular cheilosis), mouth ulcers, dry scaly skin or seborrheic dermatitis, eye problems (sensitivity to light, watery or itchy eyes, blurred vision), anemia, fatigue and slowed growth in children. Symptoms often appear with other B‑vitamin deficiencies.