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Vitamin C: the daily reference intake

The adult reference intake is 110 mg a day for men and 95 mg for women — well above the 80 mg on European labels, and far above the roughly 10 mg a day that prevents scurvy. Smokers get the only intake adjustment for a habit anywhere in the EFSA tables: an extra 35 mg a day.

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.

Vitamin C by age, sex and life stage

EFSA adds 35 mg a day to the adult value for smokers, on evidence of faster metabolic turnover. It is the only nutrient in this table with a smoking adjustment.

Three different numbers, three different questions

Around 10 mg a day prevents scurvy. That is the deficiency threshold and it is not the reference intake. EFSA set 110 mg for men and 95 mg for women on the basis of the intake needed to maintain a defined body pool with an adequate margin, which is a different and higher endpoint. The European label reference is 80 mg, a legal denominator fixed separately.

When a supplement advertises "1 000 mg, over 1 000% of your daily requirement", all three of those numbers are being blurred together. The honest reading is that it is roughly nine times the adult reference intake, and that the excess is excreted.

The smoker adjustment

Smoking accelerates the metabolic turnover of vitamin C, and EFSA added 35 mg a day to the adult reference intake for smokers to compensate. It is worth noticing what the adjustment is not: it is a correction so that a smoker reaches the same body pool as a non-smoker, not a claim that vitamin C offsets any of the harm of smoking.

What it actually does, and does not do

Vitamin C is required for collagen synthesis, which is why scurvy presents as bleeding gums and poor wound healing. It also markedly increases the absorption of non-haem iron from plant foods eaten in the same meal, which is the most useful practical fact on this page for anyone eating little or no meat.

The claim it is best known for is the weakest. Reviews of regular vitamin C supplementation in the general population find no meaningful reduction in how often adults catch a cold; a small shortening of duration has been reported. Marathon runners, skiers and soldiers under short-term extreme physical stress are the exception in that literature.

It is the nutrient most easily destroyed by the kitchen

Vitamin C is water-soluble, heat-sensitive and oxidises on cutting and standing. Boiling vegetables in a lot of water and pouring the water away removes much of it; steaming, quick cooking and eating some raw food keep it. Fresh, frozen and cooked figures for the same vegetable can differ by half, and the food table below uses the composition data as published for each form.

The upper level

EFSA has not set a tolerable upper intake level for vitamin C. Gram doses commonly cause diarrhoea and abdominal discomfort, and can interfere with some laboratory tests, including glucose meters and faecal occult blood tests.

Ordinary food against the 110 mg male reference intake

Top of this list: Black currant, 181 mg in a 100 g serving (a cupful) — 165% of the 110 mg male reference intake. One serving covers the whole day on its own.

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.

For the full ranking of every food in the database by vitamin c per 100 g, see foods highest in vitamin c.

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 vitamin C (2013) · Regulation (EU) No 1169/2011, Annex XIII · checked 2026-09-06

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