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Nutrition Library

Vitamin K

kale
General Information
  • Vitamin K is one of the fat-soluble vitamins.
  • Vitamin K is a collective term for various substances. Specifically, vitamin K1 = phylloquinone, vitamin K2 = menaquinone, and vitamin K3 = menadione (synthetically produced).
  • Vitamin K2 is likewise a collective term for different menaquinones.
  • Vitamin K1 is part of the photosynthetic system in green plants and is therefore found primarily in green vegetables. Vitamin K2 is formed by microorganisms (also partly from vitamin K1) and, apart from animal products, is mainly found in fermented foods.
  • With a balanced and varied diet, supply of vitamin K is usually adequate.
  • An imbalanced diet with too many industrially manufactured foods may lead to a deficiency. In addition, fat digestion disorders, fat-blocking medications, and antibiotics can reduce vitamin K-producing intestinal flora. The most significant is a deliberate iatrogenic deficiency caused by taking coumarin-type blood thinners (anticoagulants).
Why Do We Need Vitamin K?

Vitamin K1 mainly for:

  • blood clotting

Vitamin K2 mainly for:

  • Influences bone metabolism with mineralization of bone substance and teeth
  • Cartilage mineralization
  • Influences lipid metabolism
  • Influences vascular integrity, maintains suppleness, and prevents deposits on the arterial walls, articular cartilage, and other soft tissue in the body
Possible Causes of Deficiency

Inadequate intake:

  • Diet low in foods containing vitamin K (see below)

Increased requirements:

  • Newborns
  • Competitive athletes
  • Fractures
  • Osteoporosis

Reduced absorption:

 

  • Gastrointestinal disorders (e.g., Crohn’s disease, ulcerative colitis, liver and/or bile disorders, pancreatic insufficiency, celiac disease, cystic fibrosis)

Interaction with medication (impaired absorption/utilization):

  • More vitamin K is needed when taking vitamin E supplements > 800 IU per day
  • Vitamin K metabolism disorders caused by antibiotics (cephalosporins, ampicillin, sulfonamides, tetracyclines), antiepileptics (e.g., carbamazepine, phenytoin, valproic acid), colestyramine, orlistat

Vitamin K reduces the effect of blood thinners (vitamin K antagonists). This is true even for low doses (below 45 µg).

If you are taking a vitamin K antagonist as a blood thinner (e.g., Falithrom, Marcumar), talk to your doctor if you are planning to change your diet and thereby increasing your vitamin K intake. The dosage of your medication may need to be adjusted.

Symptoms of Deficiency
  • General: loss of appetite, diarrhea, increased risk of bleeding, increased bleeding after surgery
  • Blood: blood coagulation disorders with prolonged clotting time, nosebleeds, menorrhagia, hematuria etc.
  • Bones: low bone density, disruption of bone structure
  • Increased risk of hardening of the arteries, osteoporosis
Recommended Intakes

The recommended intake applies to vitamin K in general and does not specify vitamin K1 vs K2.

Recommended intake for adults:

  • according to D-A-CH: women aged 19-51 60 µg/day, women aged 51+ 65 µg/day
  • Men aged 19-51 70 µg/day, men aged 51+  80 µg/day
  • USA Food and Nutrition Board (FNB): women 90 µg/day, men 120 µg/day

Pregnant women (> 19 years):

  • according to D-A-CH: 60 µg/day
  • USA Food and Nutrition Board (FNB): 90 µg/day

Breastfeeding women (> 19 years):

  • according to D-A-CH: 60 µg/day
  • USA Food and Nutrition Board (FNB): 90 µg/day

Children and adolescents, depending on age, see

 

The Best Plant Sources (per 100 g)

Vitamin K1 is mainly found in green leafy vegetables such as spinach, broccoli, and cabbage. Among plant-based foods, Vitamin K2  is found primarily in fermented foods.

Since vitamin K is heat and light stable, the amount available in dried foods remains very high. Dried herbs and spices thus contain a lot of vitamin K.

Some foods contain both forms, but others contain only one of the two. Often, the amount of vitamin K listed for a food is the total amount.

  • Vitamin K1:
    • Kale 800 µg
    • Parsley leaves, fresh 790 µg
    • Parsley leaves, frozen 827 µg
    • Chives, fresh 605 µg
    • Swiss chard 400 µg
    • Purslane 380 µg
    • Spinach 300 µg
    • Grapeseed oil 280 µg
    • Broccoli 270 µg
    • Rocket/arugula 250 µg
    • Brussels sprouts 250 µg
    • Pak Choi 250 µg
    • Chinese cabbage 250µg
    • Watercress 250 µg
    • Fennel 240 µg
    • Cauliflower 200 µg
    • Soybean flour 200 µg
    • Lamb’s lettuce 200 µg
    • Green bean, dried 180 µg
    • Mung beans, dried 170 µg
    • Chickpeas, dried 165 µg
    • Lettuce 130 µg
    • White cabbage 80µg
    • Sauerkraut 80 µg
    • Oatmeal 60 µg
    • Soybean, fresh 60 µg
    • Asparagus 45 µg
    • Potatoes 25 µg
    • Green beans 25 µg

 

  • Vitamin K2:
    • Natto 998 µg
    • Sauerkraut 10 µg
Sources

  • Biesalski, H.K., Bischoff, S.C., Pirlich, M., Weidmann, A., (2018). Ernährungsmedizin – Nach dem Curriculum Ernährungsmedizin der Bundesärztekammer (5.Auflage). Stuttgart: Georg Thieme Verlag

  • Roman Viñas B, Ribas Barba L, Ngo J, Gurinovic M, Novakovic R, Cavelaars A, de Groot L.C.P.G.M, van’t Veer P, Matthys C, Serra Majem L., Projected prevalence of inadaquate nutrient intakes in Europe. Ann Nutr Metab 2011, 59:84–95

  • Gröber, U. (2011): Mikronährstoffe. Metabolic Tuning – Prävention – Therapie. 3. Aufl. Wissenschaftliche Verlagsgesellschaft mbH Stuttgart

  • https://www.dge.de/wissenschaft/referenzwerte/selen/