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Vitamin K: the daily reference intake
Vitamin K has a modest adequate intake — 70 micrograms a day for adults — that a single portion of dark leafy greens covers many times over. It earns its own page for a different reason: it is the nutrient that interacts most directly with a very common medicine.
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 K by age, sex and life stage
EFSA set the adequate intake for phylloquinone, vitamin K1. It did not set a separate value for the menaquinones, vitamin K2, because the evidence was insufficient.
| Group | Reference value | Type | Note |
|---|---|---|---|
| Men 19-50 | 70 µg | AI | as phylloquinone |
| Women 19-50 | 70 µg | AI | as phylloquinone |
| Men 51 and over | 70 µg | AI | as phylloquinone |
| Women 51 and over | 70 µg | AI | as phylloquinone |
| Adults 65 and over | 70 µg | AI | |
| Pregnancy | 70 µg | AI | no increase in pregnancy |
| Breastfeeding | 70 µg | AI | no increase while breastfeeding |
What it does
Vitamin K is the cofactor for an enzyme that modifies specific proteins so they can bind calcium. Several clotting factors depend on it, which is why deficiency shows up as bleeding, and so do bone and vascular proteins, which is the reason vitamin K keeps appearing in bone-health research.
Newborns are the one group with a routine clinical intervention: vitamin K stores at birth are low and breast milk is a poor source, so vitamin K is given at birth as standard practice across Europe to prevent vitamin K deficiency bleeding. That is a neonatal protocol, not a dietary recommendation, and it is handled by the maternity unit.
The warfarin interaction, in the right direction
Warfarin and related anticoagulants work by blocking vitamin K recycling. More dietary vitamin K therefore reduces the drug effect, and less increases it. The standard clinical advice is not to avoid greens — it is to keep intake steady, because it is the change that destabilises the INR, not the level.
A person on warfarin who suddenly starts a daily kale smoothie, or suddenly stops one, can move their INR meaningfully in either direction. Anyone in that situation should raise it with the clinic that manages their anticoagulation rather than adjusting anything on their own.
K1 and K2 are not interchangeable in the data
Phylloquinone, K1, is the plant form and dominates the diet: dark leafy greens, broccoli, cabbage and green herbs, plus some vegetable oils. Menaquinones, K2, come from fermented foods and some animal foods, natto being by far the richest.
EFSA set its adequate intake for K1 only, judging the evidence on menaquinones insufficient. Food composition tables, including the one behind this site, generally report K1 as well. So both the reference value and the food numbers below describe the same molecule, which is at least internally consistent.
Easy to reach
A single ordinary portion of spinach, kale or broccoli passes the whole daily figure by a wide margin. Vitamin K is fat-soluble, so eating greens with some fat improves absorption — the oil in the dressing is doing something real.
The upper level
No tolerable upper intake level has been set for vitamin K. That does not make it irrelevant to safety: vitamin K directly opposes warfarin and similar vitamin K antagonist anticoagulants, and a sudden change in intake destabilises the dose.
Ordinary food against the 70 microgram adult adequate intake
Top of this list: Spinach, 386 µg in a 80 g serving (a large handful) — 552% of the 70 microgram adult adequate intake. One serving covers the whole day on its own.
| Food | Ordinary portion | Per portion | Share of the day |
|---|---|---|---|
| Spinach | a large handful, 80 g | 386 µg | 552% |
| Kale | a large handful, 80 g | 312 µg | 445% |
| Broccoli | a portion, 100 g | 102 µg | 145% |
| Cabbage | a portion, 100 g | 76 µg | 109% |
| Green beans | a portion, 100 g | 47.9 µg | 68% |
| Soybeans | a portion, cooked, 150 g | 28.8 µg | 41% |
| Green peas | a portion, 100 g | 24.8 µg | 35% |
| Avocado | half an avocado, 100 g | 21 µg | 30% |
| Cucumber | a third of a cucumber, 100 g | 16.4 µg | 23% |
| Natto | a small portion, 50 g | 11.6 µg | 17% |
| Carrot | 1 carrot, 80 g | 10.6 µg | 15% |
| Cashews | a small handful, 30 g | 10.2 µg | 15% |
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 k per 100 g, see foods highest in vitamin k.
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 K (2017) · Regulation (EU) No 1169/2011, Annex XIII · checked 2026-09-06
Frequently asked questions
How much vitamin K a day?
EFSA adequate intake is 70 micrograms a day of phylloquinone for adults, with no increase for pregnancy or breastfeeding.
Should people on warfarin avoid green vegetables?
No. The standard advice is to keep intake consistent rather than to avoid greens, because sudden changes in vitamin K intake destabilise the anticoagulant effect. Anyone on warfarin should discuss diet changes with their anticoagulation clinic.
Which foods are highest in vitamin K?
Dark leafy greens by a long way: parsley, spinach, kale, chard, collards and broccoli. Natto is the outstanding source of the K2 forms.
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.