Thiamine (Vitamin B1), also known as the “anti-stress vitamin” or aneurin, is a water-soluble B-complex vitamin that plays an indispensable role in nervous system function and brain energy metabolism. It’s often called the “mood vitamin” because of its calming effects on mental state when levels are adequate.
The body’s thiamine stores are extremely limited—after just 14 days without intake, reserves drop by about 50 %. Chronic alcohol consumption dramatically worsens this situation in several ways: it impairs active absorption in the small intestine, massively increases metabolic demand (because alcohol breakdown itself consumes thiamine), and damages storage capacity in the liver. As a result, a very high percentage of people with alcohol use disorder suffer from clinically significant thiamine deficiency, with potentially devastating health consequences.
At low to moderate concentrations, thiamine is absorbed via an active transporter in the gut; at higher concentrations it also enters passively by diffusion. Alcohol interferes with both mechanisms and simultaneously damages the intestinal lining, creating a double hit on uptake.
Thiamine is heat-sensitive and easily destroyed by cooking. It is water-soluble, so a portion leaches into cooking water (which is usually discarded). Raw fish and certain ferns contain the enzyme thiaminase, which actively breaks down thiamine. Sulfite preservatives (E220–E228), commonly used in wine, dried fruit, and processed foods, also degrade vitamin B1.
Thiamine has an exceptionally wide therapeutic window. Animal studies show that doses up to 100 times the daily requirement, given over multiple generations, produced no adverse effects when taken orally. (Intravenous administration is a different story and requires medical supervision.)
Vitamin B1 is present in nearly all plant and animal foods, but levels vary widely. The richest everyday sources include:
- Whole grains (whole-grain bread, brown rice, millet, oats)
- Legumes (beans, lentils, peas, soy)
- Pork — with roughly 1 mg per 100 g, it is by far the champion among meats
Other meats, fish, and dairy products contain significantly less. Many plant foods (especially refined grains) lose most of their thiamine during processing.
Severe, prolonged thiamine deficiency can trigger several serious conditions:
- Beriberi (dry or wet forms)
- Korsakows syndrome
- Wernicke’s encephalopathy
- Strachan syndrome (rare, mainly in malnutrition + alcohol)
Because long-term heavy drinking frequently causes multiple B-vitamin deficiencies simultaneously, Korsakoff syndrome has become almost a hallmark of chronic alcoholism in Western countries.
Bernd Guzek, MD, PhD #
Physician, author & co-founder of Bye-Bye-Booze
Specialized in biochemical mechanisms of addiction and brain metabolism.
