Vitamin K 2 wins wide backing for treating osteoporosis

    According to the November 2007 issue of the journal Clinical Calcium Vitamin K2 has gained status in treating or preventing osteoporosis according to the 2006 version of the guideline for prophylaxis and treatment of osteoporosis. According to the guidelines Vitamin K2 may be used currently with other drugs in the treatment of osteoporosis. The vitamin obtained grade B status for preventing both hip and spine fractures and for improving bone mineral density.

Low plasma Vitamin K1 is associated with high incidence of spinal fracture in Japanese women

    Scientists at Kobe Pharmaceutical University in Japan note it has been reported that vitamin K supplementation effectively prevents fractures and maintains bone mineral density in people treated for osteoporosis. The objectives were to evaluate the association between plasma K1 or K2 as MK-4 and MK-7 concentration and bone health or fracture in Japanese women. A total of 379 healthy women aged 30-88 years (average age of 63) were consecutively enrolled. Plasma K1, MK-4, MK-7, BMD (bone mineral density) and incidence of vertebral fractures of the spine were evaluated. A low level of Vitamin K1was independently correlated with vertebral (spinal) fracture incidence. When subjects were divided into low and high K1 groups by plasma K1 concentration, the incidence of vertebral fracture in the low K1 group (14.4%) was significantly higher than that in the high K1 group (4.2%),. Those with a low level of Vitamin K1 had a 358% increased risk of fracturing their spine and this is independent of osteoporosis. The study is published online ahead of print in the Journal of Bone and Mineral Metabolism.

Vitamin K1 intake is associated with higher bone mineral density and reduced bone resorption in early postmenopausal Scottish women

     Researchers measured bone mineral density (BMD) at the lumbar spine (LS) and femoral neck (FN; this is where the hip fractures) in a cohort of Scottish women aged 49–54 years in 1990–1994 (baseline) and in 1997–2000 (visit 2). Women with the lowest 25% of Vitamin K intake had lower BMD especially at the FN after adjustment for age, weight, height, menopausal status or use of hormone replacement therapy, socioeconomic status, and physical activity. The study is published in the May 2008 issue of the American Journal of Clinical Nutrition.

Vitamin K2 may reduce the risk of prostate cancer

     Vitamin K has displayed cancer fighting, cancer preventing activity in various cell lines including those of prostate cancer. This is the first epidemiological study to examine a relationship between Vitamin K levels and prostate cancer incidence.

     Researchers from the Division of Cancer Epidemiology, German Cancer Research Centre in Heidelberg followed 11,319 men for 8.6 years on average. There was a 45% decreased risk of developing prostate cancer in men with higher intake of Vitamin K2. There was a 63% decreased risk of developing advanced prostate cancer in men with a higher intake of Vitamin K2. There was no connection with Vitamin K1. The study is published in the April 2008 issue of the American Journal of Clinical Nutrition.

High dose Vitamin K1 and K2 (as Menaquinone 4) may reverse calcification in the arteries

     Vitamin K1 (also known as Phylloquinone and Phytonadione) is found in green leafy vegetables such as broccoli, lettuce and spinach; K1 makes up about 90% of the vitamin K in our diet. Most forms of Vitamin K2 are formed by healthy bacteria in our intestines. Different versions of Vitamin K2 are referred to as Menaquinone with various numbers after it; they make up about 10% of our Vitamin K intake. The bacteria do not make Menaquinone-4 but a small amount is found in meat. Menaquinone-7 is from fermented foods such as Natto.

     Calcification of the arteries is a major part of arterial disease and hardening of the arteries. Hardening of the arteries is a key part of cardiovascular disease and coronary heart disease; the cause of over 50% of all deaths in the USA. The level of calcification of blood vessels predicts future stroke and heart attack risk.

     In this study researchers from Maastricht University in the Netherlands fed 10 week old rats a higher dosage of the blood thinner warfarin (Coumadin) to cause a build up of calcium in their blood vessels for a six-week period. Vitamin K intake was at normal dietary levels at this point. Warfarin at high doses can contribute to calcification by inactivating Vitamin K dependent matrix GLA protein. Matrix GLA protein helps keep calcium out of the arteries and brings it to the bone where it belongs. The animals were then supplemented with either high dose K1 or K2 as Menaquinone-4 for an additional six-weeks.

     If warfarin was stopped, calcification continued to occur over the next six-weeks at normal Vitamin K levels. However, with the removal of warfarin and the start of the high dose Vitamin K therapy the further accumulation of calcification in the arteries was stopped. In fact it was better than this; adding high dose Vitamin K reversed existing arterial calcifications by 37% within six-weeks. The higher levels of Vitamin K were needed to reactivate matrix GLA protein (a normal level of Vitamin K intake was not protective because it could not restart the matrix GLAS protein). The study appears in the April 1st, 2007 issue of the journal Blood.

New research has concluded vitamin K2 consumption can aid recovery from hip fractures as well as benefiting osteoporosis

     Japanese researchers found a link between vitamin K2 and prevention of hip fractures and also decreasing the incidence of osteoporosis, and suggested a review of the, "dietary reference value of vitamin K from the perspective of osteoporosis would be useful." The current Japanese reference value is 55mcg for women and 65mcg per day for men. In the US and Canada it is 120mcg per day for men and 90mcg per day for women. In France the limit is 65mcg per day for both men and women. "Since regions which consumed a lot of vitamin K, especially vitamin K2, showed a low incidence of hip fracture, we considered that vitamin K intake, not absorption, of over 300 mcg per day would be helpful to reduce the incidence of hip fracture," the researchers concluded.
The study assessed population diets in various regions of Japan as well as dietary differences, and found that those regions where certain vitamin K2-rich fruits and vegetables were prominent had reduced rates of hip fracture. "There was also a striking pattern of high intake of vitamin K and low incidence of hip fracture in eastern areas of Japan, with the opposite pattern-a low intake of vegetables rich in vitamin K and a high incidence of hip fracture-in western areas," they wrote. "These findings lend support to the idea that vitamin K is an important factor explaining regional differences in the incidence of hip fracture."

    Natto, a food made from fermented soy beans, was singled out as being a particularly abundant vitamin K source. The researchers recognized that the role of Vitamin K role in assisting bone health is relatively new. "Calcium, the most studied nutrient in the area of bone health, is known for its effectiveness in retarding bone loss in postmenopausal women," they said. "Magnesium and vitamin D play important roles in calcium and bone metabolism. Vitamin K, originally recognized as a factor required for normal blood coagulation, is beginning to receive more attention for its role in bone metabolism." Estimates suggest that in the absence of primary prevention the number of hip fractures worldwide will increase to approximately 2.6 million by the year 2025, and 4.5 million by the year 2050. Osteoporosis weakens bone strength which increases the likelihood of hip fracture, a problem that increases with age. The study is published in the current issue of the European Journal of Epidemiology. Note; a recent headline in the November 2007 issue of Mayo Clinic Health Letter “Vitamin K linked to bone strength”.

Increased intakes of vitamin K2 decreases the risk of coronary heart disease in postmenopausal women

    For every 10 microgram increase in the amount of Vitamin K2 consumed, researchers from the Netherlands report a 9 % reduction in the risk of developing coronary heart disease (CHD). The effects were mostly confined to the higher forms of vitamin K2, namely Menaquinone 7 to 9. “Our findings may have important practical implications on CVD prevention, it is important to mention that in order to increase the intake of vitamin K2, increasing the portion vitamin K2 rich foods in daily life might not be a good idea,” wrote lead author Gerrie-Cor Gast from the Julius Center for Health Sciences and Primary Care at the University Medical Center Utrecht. “Vitamin K2 might be, for instance more relevant in the form of a supplement or in low-fat dairy.”  

    Lead researcher Ms Gast and her co-workers evaluated data from the Prospect-EPIC cohort, consisting of 16,057 post-menopausal women, aged between 49 and 70. None of the women had cardiovascular disease at the start of the study. Dietary intakes were assessed using food frequency questions (FFQs), and participants were followed for over eight years. At the end of the study, the researchers observed an association between a higher consumption of natural vitamin K2, particularly menaquinone-7, -8, and -9 and a significantly reduced prevalence of CHD. Consumption of vitamin K1 had no effect on vascular health, said the researchers (however, we know this form builds bone effectively; Jerry Hickey, R.Ph.).  

    The reason behind the different effects of K1 and K2 may be due to the different distribution of each in the body, said the researchers. K1 is primarily taken-up by the liver and then cleared from circulation, while K2 is the major form of vitamin K transported also to extra-hepatic tissues, such as vessel wall and bones-tissue.  

     “Of the subtypes of vitamin K2, it appeared that particularly MK-7, MK-8 and MK-9 affected the risk of CHD,” said the researchers. “A stronger effect of the longer subtypes could be due to a slower hepatic clearance of these subtypes, making them longer available for carboxylation reactions.” 

     Commenting on the research, Dr Leon Schurgers from the University of Maastricht said: “This study confirms our findings in the Rotterdam study, showing that increased vitamin K2 intake strongly reduces the risk of coronary heart disease.” Dr Schurgers, who was not involved with the new study, added: “Also this study showed that the reduction in CHD was tied to the longer-chain menaquinones 7, 8, and 9 - the menaquinones found most abundantly in fermented cheese. As the Western diet is likely deficient in K, supplementation or enrichment of long chain menaquinones is an obvious choice.” The study is published online ahead of print in the January 28th, 2009 edition of the journal Nutrition, Metabolism and Cardiovascular Diseases.