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.
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).
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.
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