Dec 14, 2015
Winter is here and despite it having been pretty mild so far, with the shortest day drawing close (December 21st), it is difficult not to want to curl up in a ball with a hot cup of cocoa and hibernate. With Christmas less than two weeks away staying healthy may well have completely been pushed aside making room for mince pies, mulled wine, port, stilton and any other festive treats that may be stuck under your nose.
So if you can find any room in your festive schedule for staying healthy, my advice for you is to take the K from Kris Kringle! Yes that’s right, this post is all about the magic of vitamin K!
Vitamin K was discovered in German 1929 and was named after the German word for clotting: Koagulation (The George Mateljan Foundation 2015) because of its significant role in blood clotting. This very complicated process requires twelve proteins to take place. Vitamin K works with four of these proteins and is associated with release of y-carboxyglutamate that chelates calcium ions thus permitting the binding of the blood clotting proteins to lipid membranes (Bender 2009).
Sorry, I’m probably getting a bit sciencey on you but here’s why it’s important!
Vitamin K is required for optimum bone health as it works with calcium, vitamin D and magnesium to ensure the skeleton stays strong. There are three types of Vitamin K:
K1: Phylloquinone: found in plant foods
K2: Menaquinone: made from K1 and K3 by bacteria and other micronutrients
K3: Menadione: found preformed in foods
Phylloquinone plays an important role in converting inactive osteoclacin (vitamin D) to the active form and is vital for the structural integrity of bone. Individuals, particularly postmenopausal women, with a deficiency in vitamin K are considered to be at greater risk of fracture (The George Mateljan Foundation 2015).
Vitamin K is broadly available through the diet and therefore it is unlikely you will be deficient if you have a varied diet. As suggested above, some studies have shown low levels of phylloquinone (K1) and menaquinone (K2) to be associated with increased risk of bone fracture, especially that of the hip (Kim MS 2015).
All newborn infants have a low vitamin K status. This is a combination of limited digestive capacity and the inefficiency of vitamin K to cross from the placenta to the foetus (Santorino D1 2015). For this reason infants are at increased risk of developing haemorrhagic disease (Scientific Commitee on Food 2006). It takes a number of weeks for a newborn to build up their dietary stores of vitamin K and is therefore a important and common procedure to give a newborn a single injection of vitamin K (Bender 2009).
Ok enough of the science…. where do we get it from? Well, providing you have a healthy and varied diet you can look to get your vitamin K from the following sources:
Fermented plant food
Not substantially provided in food as yet known
(The George Mateljan Foundation 2015).
United Kingdom: current reference values of Phylloquinone are thought to be sufficient base on 1µg/kg body weight/day provided by a normal, varied diet (Scientific Commitee on Food 2006).
The long of the short of it is that you should be possible to obtain all the vitamin K by eating a varied diet. Any excess is stored in the liver for future even if not eaten on a daily basis. A supplemental range of between 2-20µg should be sufficient (NHS 2015). So can you have too much? Well, currently there is not enough evidence to provide an upper limit for vitamin K however adverse effects were recorded when daily doses of up to 2000mg phylloquinone/kg body weight was administered to rats for 30 days (Scientific Commitee on Food 2006).
Vitamin A and E compete for absorption with vitamin K however this is only seen to be an issue with supplemental vitamin K and should not be a problem where phylloquinone is absorbed through the diet.
Vitamin K1 could deliberately block the ability of warfarin and other anti-coagulant drugs with possible serious or life-threatening interaction. Where prescribed, patients should seek medical advice and should be monitored for decreased prothrombin time (Bender 2009).
I am obsessed by a wintery kale salad at the moment so it would be wrong not to share it with you. Kale is the highest source of vitamin K1 aswell as being full of antioxidants and fibre, working to support winter immunity, remove the build up of Christmas excess and support a healthy digestion.
1 bag of kale (approx 500g) washed, stalks removed and chopped or torn into small pieces
2 tbsp extra virgin olive oil
2 tbsp apple cider vinegar
2 tbsp tamari (gluten free soy sauce)
1 tbsp tahini paste
1 tbsp pumpkin/sesame seeds
1 tsp salt and pepper
Optional: 1 large raw beetroot, peeled and thinly sliced
In a large bowl, pour the olive oil over the kale and massage in until the kale softens in your hands. This should take a couple of minutes.
Once soft, pour over the apple cider vinegar and tamari and massage for a further minute.
Finally spoon the tahini paste into the mix and combine until the kale is evenly coated.
Stir in the beetroot, season and sprinkle with seeds.
WARNING: this salad is so yummy you won't be able to stop making it!
Posted by Viki Marr.
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