Vitamin K

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Vitamin K is a fat-soluble vitamin found in the food sources leafy green vegetables, alfalfa, kelp, egg yolk and oily fish. There is no established Recommended Daily Amount (RDA) for Vitamin K however an Adequate Intake Value for vitamin K in the UK is considered to be 120 mcg for males and 90 mcg for females.

What is it needed for?

Vitamin K is necessary for building healthy bones and has been shown to play a role in treating and preventing osteoarthritis. It is also involved in the manufacture of blood clotting factors.


Deficiency of vitamin K is rare this is because it can be manufactured in the gut by gut bacteria however if a deficiency does manifestsymptoms may include excessive bleeding, easy bruising, appearance of ruptured capillariesand softening of bones.


Osteoporosis– Results from randomized controlled studies support the use of vitamin K alongside other nutrients from natural health products in the prevention and treatment of osteoporosis (1).

Coronary Heart Disease-The role of the different forms of vitamin K on calcification (hardening) in the arteries and the risk of coronary heart disease has been the subject of much research. An observational study involving 564 postmenopausal women showed that Vitamin K intake was not associated with calcification of the arteries (2). A further population-based study involving 4,807 men and women aged 55 years and older also showed no associated of Vitamin K intake and severe calcification of the aorta, the body’s main artery supplying oxygen to the body (3).

Insulin sensitivity-Research also suggests Vitamin K2 Supplementation improves insulin sensitivity. According to one placebo-controlled study involving forty-two healthy young male volunteers who received vitamin K2 or placebo for 4 weeks those who received the vitamin K2 experienced increased insulin sensitivity compared to those in the placebo group (4).

Our take on how Vitamin K may help you, based upon EU approved claims;

Excessive bleeding- Vitamin K contributes to normal blood clotting. In practice, this benefit is normally only utilised in the medical profession in relation to surgical procedures.

Osteoporosis and healing of bones- Vitamin K contributes to the maintenance of normal bones. It is thought to be required in the production of many proteins responsible for the structure of bone. This makes a supplement valuable in preventing bone conditions such as osteoporosis, and for ensuring the correct healing of bone following breaks or fractures, in cases where vitamin K may be deficient.

Works well with:

  • Calcium- is needed for the maintenance of normal bones. This suggests that if deficient bone structure may be affected and so supplementing with calcium may help to prevent such bone-related ailments. This would also make it a useful supplement in the support of healing following fractures and broken bones.
  • Vitamin D– contributes to normal absorption/ utilisation of calcium, normal blood calcium levels and to the maintenance of normal bones.

Safety and side effects

Vitamin K is not thought to be considered toxic to the body and therefore no Tolerable Upper Intake Level has been established. No adverse effects associated with vitamin K consumption from food or supplements have been reported in humans or animals


  1. Whelan AM, Jurgens TM, Bowles SK.  Natural health products in the prevention and treatment of osteoporosis: a systematic review of randomized controlled trials. Annals of Pharmacotherapy 2006; 40(5): 836-849
  2. Beulens JW, Bots ML, Atsma F, Bartelink ML, Prokop M, Geleijnse JM, et al. High dietary menaquinone intake is associated with reduced coronary calcification. Atherosclerosis 2009;203:489-93.
  3. Geleijnse JM, Vermeer C, Grobbee DE, Schurgers LJ, Knapen MH, van der Meer IM, et al. Dietary intake of menaquinone is associated with a reduced risk of coronary heart disease: the Rotterdam Study. J Nutr 2004;134:3100-5
  4. Hyung Jin Choi, MD, Juyoun Yu, BS, Hosanna Choi, BS, Jee Hyun An, MD, Sang Wan Kim, MD, PhD, Kyong Soo Park, MD, PhD, Hak C. Jang, MD, PhD, Seong Yeon Kim, MD, PhD and Chan Soo Shin, MD, PhD Vitamin K2 Supplementation Improves Insulin Sensitivity via Osteocalcin Metabolism: A Placebo-Controlled Trial Diabetes Care 2011 Sep; 34(9): e147-e147.