Vitamins K is found in green leafy vegetables and also vegetable oils. Vitamin K is involved in the synthesis of blood clotting proteins.
There are two types of vitamin K most commonly used as supplements. The first one is Vitamin K1 and the second is Vitamins K2. Vitamin K1 is the plant based vitamin K found in green leafy vegetables and in vegetable oils. In the body Vitamin K does function to synthesize blood clotting proteins. Vitamin K1 and K2 are fat soluble and fats enhance their absorption. Green leafy vegetables eaten raw will have a smaller percentage of vitamin K being absorbed than the same vegetables served with a fat. Some studies show an increase in absorption of nearly 400% by the addition of fat to the vegetables.
Vitamin K does interact with a few drugs. Vitamin K can undo the effects of blood clotting agents such as warfarin and other similar drugs. Patients on anti-coagulants should keep their intake of vitamin K constant so as not to interfere with the medication. Fat blocking medications, such as Xenical or Alli, can reduce the absorption of vitamins K. Low fat diets will also decrease your intake of vitamin K. Antibiotics decrease the bacteria in the gut resulting in decreased vitamin K production.
Newborn babies are at risk of developing a vitamin K deficiency. Vitamin K is low in breast milk and because babies don’t have a healthy population of vitamin K producing bacteria in their gut they are often given a vitamin K prophylactically at birth.
Vitamin K2 is found multiple forms with the two forms most used in nutritional supplementation; menatetrenone (MK-4) and menaquinone-7 (MK-7). Vitamin K1 can be converted in the colon by bacteria to the K2 form. K2 can also be converted by certain tissues in the body to K2. MK-7 is found in natto which is made form fermented soybeans. MK-7 has a longer half-life and greater biological activity than MK-4. While MK-7 is found to be more active there are limited human clinical studies on it.
Many people are using vitamin K is for its effect on osteocalcin. Osteocalcin is a protein that binds calcium to the bone matrix. This helps build stronger bones in the process. Vitamin K is essential to this process.
In Japan Vitamin K2 in the form of MK-4 has been used in dosages up to 45mg a day for the treatment of osteoporosis. At these dosages the MK-4 vitamin K help prevent fractures and bone loss in patients with Parkinson’s disease, anorexia, Alzheimer’s, postmenopausal women, stroke and more. However this dosage is as much as 400 times higher than the average daily diet. The long term safety of such a high dose is unknown. A much safer dosage would be in the range of 100-1000 ug a day.
Vitamin K22 in its MK-7 for has been found to stimulate bone formation and inhibit its re-absorption. While it is not as well researched as the MK-4 form, MK-7 with vitamin D has been approved in Singapore for the treatment of bone density.
Vitamin K can also be used in a cream form to help bruising, treat dark circles under the eyes and treat rosacea. One study found the women with viral cirrhosis treated with the MK-4 form of vitamin K were 90% less likely to develop liver cancer.
Vitamin K remains an exciting supplement with the potential for future growth in research.