Vitamin K
What it is and what it does
- Vitamin K is a family of compounds that includes phylloquinone (vitamin K1) and a series of menaquinones (vitamin K2). (NIH Office of Dietary Supplements. Vitamin K Fact Sheet for Health Professionals (updated 2021-03-29))
- Phylloquinone is found mainly in green leafy vegetables and is the main form of vitamin K in the diet. (NIH Office of Dietary Supplements. Vitamin K Fact Sheet for Health Professionals (updated 2021-03-29))
- Almost all menaquinones, especially the long-chain ones, are also made by bacteria in the human gut. (NIH Office of Dietary Supplements. Vitamin K Fact Sheet for Health Professionals (updated 2021-03-29))
- Vitamin K is a coenzyme for vitamin K-dependent carboxylase, an enzyme needed to make proteins involved in blood clotting and bone metabolism. (NIH Office of Dietary Supplements. Vitamin K Fact Sheet for Health Professionals (updated 2021-03-29))
- Prothrombin (clotting factor II), a vitamin K-dependent protein in blood plasma, is directly involved in blood clotting. (NIH Office of Dietary Supplements. Vitamin K Fact Sheet for Health Professionals (updated 2021-03-29))
- Osteocalcin, another vitamin K-dependent protein, is present in bone and may be involved in bone mineralisation or turnover. (NIH Office of Dietary Supplements. Vitamin K Fact Sheet for Health Professionals (updated 2021-03-29))
Why it matters
- Bleeding and haemorrhage are the classic signs of vitamin K deficiency, but they occur only in severe cases. (NIH Office of Dietary Supplements. Vitamin K Fact Sheet for Health Professionals (updated 2021-03-29))
- Clinically significant vitamin K deficiency in adults is very rare. (NIH Office of Dietary Supplements. Vitamin K Fact Sheet for Health Professionals (updated 2021-03-29))
- Deficiency can occur in the first few weeks of infancy, partly because little phylloquinone crosses the placenta. (NIH Office of Dietary Supplements. Vitamin K Fact Sheet for Health Professionals (updated 2021-03-29))
- Too much: no US upper limit (UL) has been set, because vitamin K has a low potential for toxicity. (NIH Office of Dietary Supplements. Vitamin K Fact Sheet for Health Professionals (updated 2021-03-29))
- People taking warfarin or similar blood thinners need a consistent intake of vitamin K from food and supplements. (NIH Office of Dietary Supplements. Vitamin K Fact Sheet for Health Professionals (updated 2021-03-29))
General information, not medical advice — for your own needs, ask a doctor or dietitian.
How much is needed
| Who | Amount | What the figure is | Whose figure |
|---|---|---|---|
| Adults | 55 ug/day | Recommendation | ICMR-NIN 2020 |
| Adult men, 19+ years (US) | 120 ug/day | AI (adequate intake) | US NASEM via NIH ODS (not an Indian value) |
| Adult women, 19+ years (US) | 90 ug/day | AI (adequate intake) | US NASEM via NIH ODS (not an Indian value) |
| Pregnancy and lactation, 19+ years (US) | 90 ug/day | AI (adequate intake) | US NASEM via NIH ODS (not an Indian value) |
India’s own figure (ICMR-NIN 2020) comes first. Figures from other bodies are shown only where they help, and say whose they are.
Sources: ICMR-NIN Expert Group. Short Report of Nutrient Requirements for Indians: Recommended Dietary Allowances and Estimated Average Requirements - 2020; NIH Office of Dietary Supplements. Vitamin K Fact Sheet for Health Professionals (updated 2021-03-29)
In every millet and pseudo-cereal, per 100 g raw
| Grain | Amount | Source |
|---|---|---|
| Jowar (sorghum) | 43.82 µg | IFCT A005 |
| Little millet | 4.47 µg | IFCT A016 |
| Kodo millet | 3.75 µg | IFCT A017 |
| Ragi (finger millet) | 3 µg | IFCT A010 |
| Bajra (pearl millet) | 2.85 µg | IFCT A003 |
| Rajgira (amaranth) | 2.5 µg | IFCT A002 |
| Quinoa | 2 µg | IFCT A009 |
| Teff | 1.9 µg | USDA FDC 169747 |
| Proso millet | 0.9 µg | USDA FDC 169702 |
Each grain has ONE source, named on its page: IFCT = Indian Food Composition Tables 2017 (ICMR-NIN) with its food code; USDA FDC; FAO WAFCT 2019; NIN 2007 via ICAR-IIMR. Values exactly as printed, not converted — tables differ in method, so compare within a source. Published values for the grain, not a laboratory test of our packs.
Absorption and food
- Phylloquinone in plant foods is tightly bound to chloroplasts, so less of it is absorbed than from oils or supplements. (NIH Office of Dietary Supplements. Vitamin K Fact Sheet for Health Professionals (updated 2021-03-29))
- Eating vegetables together with some fat improves phylloquinone absorption from them. (NIH Office of Dietary Supplements. Vitamin K Fact Sheet for Health Professionals (updated 2021-03-29))
- Fats carry the fat-soluble vitamins A, D, E and K and help their absorption. (ICMR-NIN. Dietary Guidelines for Indians 2024)
- Antibiotics can destroy the gut bacteria that make vitamin K, which may lower vitamin K status. (NIH Office of Dietary Supplements. Vitamin K Fact Sheet for Health Professionals (updated 2021-03-29))
- Phylloquinone (K1) is found in vegetables, especially green leafy vegetables, and in vegetable oils and some fruits. (NIH Office of Dietary Supplements. Vitamin K Fact Sheet for Health Professionals (updated 2021-03-29))
- Green leafy vegetables such as spinach, kale, broccoli and lettuce contain vitamin K. (NIH Office of Dietary Supplements. Vitamin K Fact Sheet for Consumers (updated 2021-03-22))
- Fermented foods such as cheese contain menaquinones (K2). (NIH Office of Dietary Supplements. Vitamin K Fact Sheet for Health Professionals (updated 2021-03-29))