| People are often confused about which vitamin K | | | | 45mg/day of MK-4 have reported significant |
| supplement is best for their personal needs. Research | | | | reductions in the rate of bone loss. (J Orthop Sci. |
| suggests that vitamin K1 is most effective at | | | | 2001;6(6):487-492. and Annu Rev Nutr. 1995;15:1-22) |
| supporting healthy insulin levels. Vitamin K2 plays a | | | | A meta-analysis of seven Japanese randomized |
| vital role in ensuring that calcium stays in the bones | | | | controlled trials indicated that MK-4 supplements |
| and out of the arteries. It may also protect the heart | | | | increased bone mineral density and reduced fracture |
| and inhibit cancer. | | | | incidence. The studies also indicated lowered risk for |
| Vitamin K was first recognized in 1929 for its vital | | | | vertebral fractures by 60%, hip fractures by 77%, |
| role in the blood-clotting process. Research now | | | | and nonvertebral fractures by 81%. (Arch Intern Med. |
| shows that Vitamin K1 and Vitamin K2 have distinct | | | | 2006;166(12):1256-1261) A 45 mg/day dose of MK-4 |
| benefits and are found in very different foods. | | | | supplements used in a 3-year placebo-controlled |
| Studies have shown that vitamin K2 is particularly | | | | study of 325 postmenopausal women also found |
| effective for the treatment of osteoporosis, heart | | | | improved measures of bone strength compared to a |
| disease and various forms of cancer. | | | | placebo.(Osteoporos Int. 2007;18(7):963-972) In |
| AN INTRODUCTION TO VITAMIN K | | | | Japan, MK4 has been an approved medication for |
| There are two main forms of vitamin K. Vitamin K1 | | | | osteoporosis since 1995. |
| (phylloquinone) is found in green leafy vegetables and | | | | Vitamin K2 (MK-7) |
| makes up about 90 per cent of the vitamin K in a | | | | Vitamin K supplements in the form of MK-7 are |
| typical western diet. Vitamin K2 (menaquinones) | | | | derived from fermented soy (natto) and are |
| makes up about 10 per cent of western vitamin K | | | | generally more expensive than MK-4 supplements. |
| consumption and can be synthesized in the gut by | | | | Research conducted in Japan has been very |
| microflora. | | | | encouraging regarding the contribution of MK-7 to |
| Vitamin K2 is actually a group of compounds known | | | | improved bone health. A study of 944 women (20-79 |
| as menaquinones or MK-n. MK-7, MK-8, and MK-9 are | | | | years old) over three years found that dietary natto |
| found in fermented food products like cheese and | | | | intake helped to increase bone mineral density (BMD) |
| natto-a popular fermented soy product found in | | | | in the hips of postmenopausal women and slowed |
| Japan. Natto is a particularly rich source of MK-7. | | | | the loss of BMD in the femoral neck and the forearm. |
| MK-4 is distinct from other MKs because it is not | | | | (2006 American Society for Nutrition J. Nutr. |
| produced in significant amounts by bacteria but | | | | 136:1323-1328, May 2006) |
| appears to be synthesized by animals and humans | | | | Supplement manufactures argue that MK-7 remains in |
| from the phylloquinone in plants and also from | | | | the blood longer than MK-4 but there are no |
| menadione- a synthetic form of vitamin K present in | | | | published studies demonstrating that this claim has |
| animal feed. In Japan, MK-4 has been an approved | | | | been clinically proven or that a longer plasma half-life |
| medication for osteoporosis since 1995. | | | | is beneficial to bone health. |
| VITAMIN K2 SUPPLEMENTS | | | | It is clear from the above studies that both MK-4 |
| Vitamin K2 supplements of both MK-4 and MK-7 are | | | | and MK-7 are excellent for bone health. However, the |
| readily available throughout North America. An MK-4 | | | | research does not clearly demonstrate that MK-7 |
| supplement (45 mcg) can cost as little as 4 cents a | | | | produces superior results and therefore warrants the |
| tablet, while an MK-7 tablet of 50 mcg will cost about | | | | additional cost of the supplements. |
| 25 cents for a softgel. | | | | *** Note that anyone who has a heart condition or is |
| Is MK-7 worth the extra money? Here is what the | | | | taking anti-coagulants (blood thinners) such as |
| research says. | | | | Warfarin or Coumadin should only take vitamin K |
| Vitamin K2 (MK-4) | | | | supplements on the advice of a doctor. |
| In Japan, studies with osteoporotic women using | | | | |