Vitamins C, B and D are probably known to most people – and many have probably taken these vitamins as dietary supplements. However, there are other lesser known vitamins that are important for your general health. One of these is vitamin K.

Vitamins are essential nutrients

Vitamins are classified as so-called essential nutrients, which means that the body can’t produce enough of these on its own and that they are vital for your general health. These nutrients therefore need to be ingested externally via, for example, diet, supplementation or, as in the case of vitamin D, via the sun. In addition to vitamins, the fatty acids omega-3 and omega-6, nine amino acids, as well as certain minerals and trace elements such as calcium, magnesium and iodine are also classified as essential nutrients.

That’s why you need vitamin K.

Vitamin K consists of the fat-soluble vitamins K1 (phylloquinone) and K2 (menaquinone). Together, these vitamins have an effect on several important functions in the body that keep us strong and healthy.

• Healing wounds – The proteins needed for the blood to coagulate are dependent on vitamin K. It may therefore take longer for the blood to coagulate and for wounds to heal in people who are deficient in vitamin K.
• A strong skeleton – Vitamin K supports bone mineralisation and calcium balance in the body, which contributes to maintaining a normal bone structure.
• Cardiovascular health – Vitamin K helps keep the heart and blood vessels strong and flexible by protecting against calcification.
• Vitamin D uptake – Vitamin K is required for the uptake of vitamin D, as K2 helps introduce vitamin D into the skeleton.
• Cognitive effect – Research also suggests that vitamin K may be linked to brain function and that vitamin K deficiency could increase the risk of dementia.

Sources of vitamin K

K1 – green leafy vegetables

Vitamin K1 is found in green vegetables such as spinach, chard, broccoli, kale, Brussels sprouts, arugula and herbs such as oregano, parsley, coriander and basil. Vegetables such as squash, asparagus, sugar peas, fresh soybeans, cucumbers and avocados also contain K1.

K2 – produced by the intestinal bacteria

Vitamin K2 is mainly found in animal foods such as egg yolks, certain dairy products and in offal, but can also be found in fermented foods and algae.

However, the body can convert K1 to K2 via the gut flora, so a varied diet rich in green vegetables usually provides the body with enough of both vitamin K1 and K2. In addition to containing K1, high-fibre vegetables also provide food for the intestinal bacteria, which helps them thrive and produce more K2 and other useful vitamins such as the B vitamins biotin, folate and riboflavin.

Recommended dose

Vitamin K deficiency is relatively uncommon, but can occur when nutrient uptake is poor, or in connection with antibiotic treatment. The recommended daily dose of vitamin K1, as established by the European Food Safety Authority, is 70 micrograms per day for adults. However, the body’s capacity to store vitamin K is low and it is therefore important to consume a varied diet with lots of vegetables to meet the body’s requirement for vitamin K. Foods rich in K vitamins should also be combined with a source of fat to ensure that these vitamins are properly absorbed.

References:

The National Food Administration

Weber, P. (2001). Vitamin K and bone health. Nutrition, 17 (10), 880-887.

DiNicolantonio, J. J., Bhutani, J., & O’Keefe, J. H. (2015). The health benefits of vitamin K. Open Heart, 2 (1)

Presse, N., Belleville, S., Gaudreau, P., Greenwood, C. E., Kergoat, M., Morais, J. A., … Ferland, G. (2013). Vitamin K status and cognitive function in healthy older adults. Neurobiology of Aging, 34(12)