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Thiamin (B1): the daily reference intake
Thiamin is one of two nutrients here with no fixed daily number: EFSA sets it per megajoule of energy eaten — 0.1 mg per MJ, at every age from seven months upwards. Eat more, need more, because thiamin is consumed in the process of turning carbohydrate into energy.
These are published population reference values, not a diagnosis and not a prescription. A reference intake describes what covers a healthy group; it cannot tell you your own status, and no page can. Pregnancy, chronic illness, medicines and malabsorption all change the picture — take those questions to a doctor, midwife, pharmacist or dietitian.
The requirement at different energy intakes
Thiamin is not published as a number of milligrams per day. EFSA sets it at 0.1 mg per megajoule of energy intake for everyone from 7 months of age upwards, so the daily figure follows how much you eat.
| Energy intake | Roughly | Requirement |
|---|---|---|
| 6 MJ | 1 434 kcal | 0.6 mg |
| 8 MJ | 1 912 kcal | 0.8 mg |
| 10 MJ | 2 390 kcal | 1 mg |
| 12 MJ | 2 868 kcal | 1.2 mg |
| 14 MJ | 3 346 kcal | 1.4 mg |
Why the requirement scales with energy
Thiamin diphosphate is the coenzyme for pyruvate dehydrogenase and for transketolase — the enzymes that take carbohydrate into the citric acid cycle and through the pentose phosphate pathway. The more energy you put through those pathways, the more thiamin the machinery turns over.
That is why EFSA expresses the value per megajoule rather than per person. A sedentary adult eating 8 MJ a day needs about 0.8 mg; an active adult eating 14 MJ needs about 1.4 mg. The table below does that arithmetic across a normal range.
Refining removes it, and that has history
Thiamin lives in the germ and bran of cereal grains, and milling removes most of it. The classic consequence is beriberi, historically the disease of populations living on polished white rice, and it is the reason many countries require white flour to be fortified with thiamin.
The same principle applies quietly today: wholegrain rye and oats carry thiamin, white bread and white rice carry much less unless it has been added back. Pork is unusually rich among meats, and legumes, seeds and nuts contribute.
The alcohol connection
Chronic heavy alcohol use is the main cause of thiamin deficiency in Europe today, through poor intake, impaired absorption and increased loss together. Severe deficiency causes Wernicke encephalopathy, a medical emergency treated with injected thiamin. This is a hospital matter and not something to manage with a supermarket supplement, but it is the reason thiamin is checked and given routinely in alcohol-related admissions.
Two things that destroy it
Thiamin is heat-labile and water-soluble, so long boiling in plenty of water loses a lot of it. Sulphite preservatives also destroy thiamin, which is worth knowing about heavily sulphited products. Neither effect matters much in a varied diet with wholegrain in it.
The upper level
No tolerable upper intake level has been set for thiamin. Excess is excreted in urine.
Ordinary food against the requirement at a 10 MJ energy intake
Top of this list: Boneless pork chop, 0.768 mg in a 120 g serving (a chop) — 77% of the requirement at a 10 MJ energy intake. It would take about 2 of those to cover a full day from that one food, which is why a real diet spreads it across several rows.
| Food | Ordinary portion | Per portion | Share of the day |
|---|---|---|---|
| Boneless pork chop | a chop, 120 g | 0.768 mg | 77% |
| Sunflower seeds | 2 tbsp, 30 g | 0.444 mg | 44% |
| Black beans | a portion, cooked, 150 g | 0.36 mg | 36% |
| Salmon | a fillet, 120 g | 0.336 mg | 34% |
| Brown rice | a portion, cooked, 180 g | 0.324 mg | 32% |
| Whole-wheat pasta | a portion, cooked, 200 g | 0.32 mg | 32% |
| Lentils | a portion, cooked, 180 g | 0.306 mg | 31% |
| Wheat germ | 2 tbsp, 15 g | 0.282 mg | 28% |
| Green peas | a portion, 100 g | 0.27 mg | 27% |
| Hulled hemp seed | 2 tbsp, 20 g | 0.256 mg | 26% |
| Flaxseed | 1 tbsp, 15 g | 0.246 mg | 25% |
| Soybeans | a portion, cooked, 150 g | 0.24 mg | 24% |
Portion sizes are ordinary household servings chosen for this table, not official reference portions, and the shortlist is an editorial one: everyday foods eaten in this region rather than the highest per-100 g entries in the database. A raw per-100 g ranking would be topped by dried herbs, drink powders and fortified breakfast cereals, which answers a different question. The composition data is American, so where US fortification practice differs from European practice the row carries a dagger and the reason. For the full per-100 g ranking of a nutrient, the food-data section of this site publishes one.
Sources: EFSA Dietary Reference Values · Regulation (EU) No 1169/2011, Annex XIII · USDA FoodData Central SR Legacy (food composition) · EFSA scientific opinion on dietary reference values for thiamin (2016) · Regulation (EU) No 1169/2011, Annex XIII · checked 2026-09-06
Frequently asked questions
How much thiamin a day?
EFSA sets 0.1 mg per megajoule of energy intake at every age from 7 months. For an adult eating 10 MJ a day that is 1.0 mg; at 14 MJ it is 1.4 mg.
Which foods contain thiamin?
Wholegrain cereals, pork, legumes, seeds and nuts. Refining removes most of the thiamin from grain, which is why white flour is fortified in many countries.
Who is at risk of thiamin deficiency?
In Europe, chronic heavy alcohol use is the main cause. Severe deficiency causes Wernicke encephalopathy, which is a medical emergency treated in hospital.
See your own numbers, not the population average
TempoLife logs what you eat and adds it up, so you can compare a real week against the reference intake on this page instead of guessing.