Health & FitnessThe Nutri CentreVitamin K: An emerging role in bone and cardiovascular health Vitamin K: An emerging role in bone and cardiovascular health
13/09/2007
Although the "K" in vitamin K is derived from the German word "koagulation", nowadays scientists are recognising other important functions for vitamin K beyond its role in wound healing. Two main areas of scientific interest are in reducing the risk of osteoporosis and in cardiovascular health, where there is evidence that it can help prevent hardening of the arteries.
Vitamin K applies to a group of homologous fat-soluble compounds. These are important in activating protein, (amino acid chains), that perform a range of biochemical functions. There are two main types of vitamin K; vitamin K1 or phylloquinone is found in leafy vegetables such as cauliflower, Brussels sprouts, broccoli and vegetable oils. Vitamin K2, a range of vitamin K forms known as menaquinone-n (MK-n), is found in fermented foods such as sauerkraut, cheese and natto, a form of fermented soya beans popular in Japan. Vitamin K2 is also synthesised naturally in the body by bacteria in our small intestine, but it is not clear how much of our daily needs this provides.
Although uncommon in adults, vitamin K deficiency can occurs with diseases that prevent the absorption of fat such as liver diseases, cystic fibrosis and coeliac disease, where adults are treated with antibiotics that kill the bacteria in the digestive tract or if antagonist anticoagulant drugs are being administered. Common deficiency symptoms include bleeding gums and skin that is easily bruised.
Current guidelines recommend we have 1 microgram of vitamin K per kilogram of body weight. But and it is not specified if this should be K1 or K2. This means that an average person would need around 80 micrograms a day, the amount found in a portion of leafy green vegetables. In 1994, a Government-funded study found that many of the over-65s failed to reach their daily vitamin K target. Given this and with knowledge building about other benefits beyond wound healing, it may be a good idea to boost intake of vitamin K.
Full Spectrum Vitamin K from The Nutri Centre is a comprehensive vitamin K formula containing vitamin K1 and two forms of vitamin K2 with other fat-soluble antioxidant cofactors, such as vitamins A, D and E (as gamma- and delta-tocotrienols). Take 1 or 2 soft gels daily, or as directed by a health care practitioner.
Studies suggest that whereas vitamin K1's role is mainly in blood clotting, vitamin K2 has far wider functions. Following work at Cambridge University, which found that vitamin K reduced the process of hardening of the arteries, the British Heart Foundation is now advising patients who are undergoing dialysis to increase their intake of vitamin K as they are particularly prone to hardened arteries. Professor Cathy Shanahan, a senior research fellow at the BHF said that from the studies done so far, we should all be eating more vitamin K-rich foods. It may be no coincidence that the Japanese who eat natto, and the French who eat a lot of cheese, have much lower levels of heart disease than many other nations.
In trials at the University of Maastricht, researchers in the Cardiovascular Research Institute found that a diet rich in vitamin K2 for six weeks, halted hardening of the arteries and in fact reduced existing hardening by 37 per cent. Hardened arteries cause the blood vessel walls to lose their elasticity, so the heart has to work harder. The extra strain can lead to coronary heart disease and doubles the risk of a heart attack. Often starting with an injury as simple as a knock, the blood vessel wall becomes inflamed and then debris and cholesterol build up on the site and as a result the vessel wall starts to harden or calcify. Vitamin K seems to work by stopping the chain of events that lead to hardened arteries; it prevents initial inflammation of the vessel wall so it can simply heal itself.
Vitamin K has also been found to be vital for bone health. It’s needed for the production of an amino acid called Gla which acts as a glue to help keep calcium in the bones. A double-blind, placebo controlled study reported in Osteoporosis International early in 2007 followed 325 apparently healthy, non-osteoporotic women for three years. In the study, postmenopausal women who took a daily supplement of vitamin K2 showed improved bone mineral content and femoral neck width - measurements to the width of the neck of their hip bone- so the researchers concluded that vitamin K2 intake may contribute to preventing postmenopausal bone loss.
This supports evidence from an American study called the Nurses Health study, which monitored 72,000 women over ten years and found that those with the lowest intake of vitamin K had a 30 per cent increased risk of a hip fracture. In this study those who ate vitamin K rich lettuce daily, had a 50 per cent reduced risk of hip fracture.
Although further research is required to establish the exact relationship between vitamin K nutritional status and bone and cardiovascular health, indications show that this vitamin may have much to offer.
Full Spectrum Vitamin K by Allergy Research Group costs £29.99 for 90 softgels.
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