What it does in the body
- Pyruvate dehydrogenase cofactor (carbohydrate metabolism gateway)
- Alpha-ketoglutarate dehydrogenase cofactor (TCA cycle)
- Transketolase cofactor (pentose phosphate pathway / nucleotide synthesis)
- Nerve impulse conduction and neurotransmitter synthesis
- Cardiac muscle contractility
How much you need (Daily Value)
| Group | Recommended | Source |
|---|---|---|
| Adult male | 1.2 mg | NIH/IOM |
| Adult female | 1.1 mg | NIH/IOM |
| Pregnancy | 1.4 mg | WHO/IOM |
| Children | 0.5-0.9 mg (ages 1-13) | WHO |
| Older adults | 1.2 mg (male), 1.1 mg (female) | NIH |
Richest food sources
| Food | Amount | Where |
|---|---|---|
| Pork loin | 0.96 mg per 100g | global |
| Sunflower seeds | 1.48 mg per 100g | global |
| Black beans (cooked) | 0.24 mg per 100g | Americas |
| Brown rice (cooked) | 0.18 mg per 100g | Asia |
| Enriched white rice | 0.26 mg per 100g | global |
| Lentils (cooked) | 0.17 mg per 100g | South Asia/Middle East |
| Nutritional yeast | 9.7 mg per 100g (fortified) | global |
| Millet | 0.42 mg per 100g | Africa/South Asia |
In our food database, per 100 g
Highest among our free foods — open the Food Explorer to compare.
If you don't get enough
Mild: Fatigue, irritability, poor concentration, reduced appetite
Moderate: Peripheral neuropathy (dry beriberi), muscle weakness, tachycardia
Severe: Wet beriberi (high-output cardiac failure with edema), Wernicke encephalopathy (confusion, ophthalmoplegia, ataxia), Korsakoff syndrome (irreversible anterograde amnesia, confabulation)
Time to onset: Body stores last only 2-3 weeks; symptoms can appear within 2-4 weeks of total depletion
Too much
Upper limit: No established UL; excess is rapidly excreted in urine
No known toxicity from oral supplementation. Rare anaphylactic reactions reported with IV thiamine.
How well you absorb it
~5 mg/day maximum active absorption via THTR-1 and THTR-2 transporters; passive diffusion at high doses
Helped by: Allicin in garlic (forms allithiamine, lipid-soluble form), Adequate magnesium (cofactor for thiamine-dependent enzymes)
Hindered by: Alcohol (impairs absorption and increases renal excretion), Thiaminases in raw fish and shellfish, Tannins in tea and coffee, Sulfites in food preservatives
Cooking & storage
Thiamine is the most heat-sensitive B vitamin. Boiling destroys 20-50% of thiamine. Baking with baking soda (alkaline pH) destroys it almost completely. Polishing rice removes 80% of thiamine (hence enrichment programs).
Nutrisize Health totals every nutrient from what you actually eat, against targets set for your age and sex, and flags what's short — across 4,995 foods, on your device.
