What does it do?
The forgotten one you never really hear about, vitamin K’s main function in the body is its ability to prevent hemorrhaging and blood loss through its role in blood clotting, but it also plays a role in building bones.
What’s the story?
Don’t be surprised if you start to hear a lot more about the mysterious K as our knowledge of the gut, and the hugely vital role our microbiome plays in our mental and physical well-being, continues to expand. Although our main source of K comes via phylloquinones in our diet, menaquinones (another member of the vitamin K family of compounds) are produced independently by bacteria in our gut - which is pretty cool when you think about it. Although it’s currently unclear exactly how much of this second type of vitamin K our body absorbs, it’s an interesting new angle in the story of the vitamins.
How much do I need?
Adults need 1 μg (microgram) per kg of body weight per day.
So for an average man (74 kg), you need 74 μg per day. An average woman weighing around 60 kg would need 60 μg/day and so on and so forth.
Where can I find good sources?
Foods rich in vitamin K include green leafy veg such as kale, spinach and broccoli, cereal grains, soy beans (in milk, tofu, oil or on their own as edamame beans), yogurt, seeds and nuts, and vegetable oils.
Any ideas for using those ingredients?
Kale, orange and pecan quinoa/tofu and aubergine stir-fry/marmite nuts/Extra herby couscous/grilled figs with hazelnut crumble and yogurt/tofu, spinach and ginger/roasted sprouts with lemon, chilli and garlic
References
Martyn, K. (2011) Nutrition: made incredibly easy. London, Lippincott Williams & Wilkins, chp. 6.
NHS Choices (2017) Vitamin K. Available here [last accessed 5th August 2017].
U.S. Department of Health and Human Services (2016), National Institutes of Health, Office of Dietary Supplements, Vitamin K - Fact Sheet for Health Professionals. Available here.