Vitamin B1 (thiamin)
Turns carbohydrates into energy and keeps nerves and the heart working.
If you are short of it
Possible signs
- Tiredness, low energy
- Tingling or numbness in hands and feet
- Poor appetite
- Poor memory or concentration
- Palpitations (fast heartbeat)
- Muscle weakness
These signs are common and have many other causes. They are clues, not proof; a blood test and a doctor can tell.
Who is more at risk
Heavy alcohol use, diets of mostly polished white rice, weight-loss surgery, prolonged vomiting (including severe pregnancy sickness), long-term water pills, dialysis.
Foods rich in Vitamin B1 (thiamin)
| Food | Serving | Amount | women 19–50 | men 19–50 |
|---|---|---|---|---|
| Tahini (sesame paste) | 2 tablespoons | 0.37 | 34% | 31% |
| Brown rice | 1 cup cooked | 0.35 NIH | 32% | 29% |
| Black-eyed peas (lobia) | 1 cup cooked | 0.35 | 32% | 29% |
| Lentils | 1 cup cooked | 0.33 | 30% | 28% |
| Mung beans | 1 cup cooked | 0.33 | 30% | 28% |
| Fortified breakfast cereal | 1 bowl (30 g) — check the label | 0.3 | 27% | 25% |
| Kidney or white beans | 1 cup cooked | 0.28 | 25% | 23% |
| Whole-wheat bread or pita | 2 slices or 1 loaf (64 g) | 0.25 NIH | 23% | 21% |
| Pistachios | a small handful (28 g) | 0.25 | 23% | 21% |
| Green peas | ½ cup cooked (80 g) | 0.21 | 19% | 18% |
| Whole-wheat pasta or noodles | 1 cup cooked | 0.2 NIH | 18% | 17% |
| Quinoa | 1 cup cooked | 0.2 | 18% | 17% |
| Chickpeas | 1 cup cooked | 0.19 | 17% | 16% |
| Oats (porridge) | 1 cup cooked | 0.18 NIH | 16% | 15% |
Unit: mg. Share of the daily amount. Values marked NIH were checked against the food tables of the NIH Office of Dietary Supplements; the others are approximate and unchecked. Real foods vary with variety, brand, soil and cooking.
As a supplement
Thiamine (or benfotiamine). Water-soluble: excess leaves in urine.
Too much
No upper limit; high doses are rarely harmful.
How much you need each day
| Group | Recommended | Upper limit |
|---|---|---|
| Infants 0–6 months | 0.2 | — |
| Infants 7–12 months | 0.3 | — |
| Children 1–3 years | 0.5 | — |
| Children 4–8 years | 0.6 | — |
| Children 9–13 years | 0.9 | — |
| Boys 14–18 years | 1.2 | — |
| Girls 14–18 years | 1 | — |
| Men 19–30 years | 1.2 | — |
| Women 19–30 years | 1.1 | — |
| Men 31–50 years | 1.2 | — |
| Women 31–50 years | 1.1 | — |
| Men 51–70 years | 1.2 | — |
| Women 51–70 years | 1.1 | — |
| Men over 70 | 1.2 | — |
| Women over 70 | 1.1 | — |
| Pregnant 14–18 years | 1.4 | — |
| Pregnant 19–30 years | 1.4 | — |
| Pregnant 31–50 years | 1.4 | — |
| Breastfeeding 14–18 years | 1.4 | — |
| Breastfeeding 19–30 years | 1.4 | — |
| Breastfeeding 31–50 years | 1.4 | — |
Unit: mg. US/Canada Dietary Reference Intakes (National Academies), as summarised by the NIH Office of Dietary Supplements. Other countries’ values differ slightly. These are amounts for healthy people, not treatment doses.
Medicines and habits to mention to your doctor
Water pills (furosemide, thiazides)
Furosemide-type pills wash out magnesium, zinc, thiamin and calcium. Thiazides raise blood calcium, so calcium plus vitamin D supplements need a doctor’s check.
Regular alcohol
Alcohol blocks absorption and increases loss of thiamin, folate, B6, magnesium and zinc.
Page updated: 2026-10-08 · By Prof. E. Shalaan, Applied Sciences and AI (ASAI)