The Importance of Vitamin K2 for Bone and Heart Health

Doesn’t it seem odd that the US is amongst the largest consumer of dairy and calcium supplements yet has some of the highest rates of osteoporosis? An estimated 10 million Americans have osteoporosis. Osteoporosis and low bone mass together are currently estimated to be a major health threat for almost 44 million U.S. women and men aged 50 and older (representing 55% of the people aged 50 and older in the United States) and calcium consumption alone does not appear to be effective at preventing this disease.

Calcium Supplementation Appears To Be Problematic

The role of calcium alone in preventing and treating osteoporosis remains unclear — some populations with extremely low calcium intake also have extremely low rates of bone fracture, and others with high rates of calcium intake through dairy products have higher rates of bone fracture. Large Harvard studies show that those who drink one glass of milk (or less) per week are at no greater risk of breaking a hip or forearm than those who drink two or more glasses per week. When researchers combined the data from the Harvard studies with other large prospective studies, they still found no association between calcium intake and fracture risk.

Calcium supplements have been found in recent years to increase cardiovascular risk by causing calcification in arteries. In the 2010 meta-analysis by the Women’s Health Initiative, results from 11 studies involving close to 12,000 women showed that women taking calcium supplements (~1,000 mg daily) had a 27% increased risk of myocardial infarction. Furthermore, when calcium remains in the bloodstream it also means that less of the mineral is getting into the bones where it belongs, putting bones at risk of degradation and fracture.

Particularly at risk of bone loss are post menopausal women, female athletes, vegetarians, people with lactose intolerance, people with high or low TSH (Thyroid Stimulating Hormone) levels, and women with amenorrhea, anorexia, or other disordered eating. To combat this risk, doctors recommend 1200 mg of elemental calcium daily, either from dairy or supplements. Dairy consumption has been controversial due to its high saturated fat and growth hormone content (even just natural growth hormones present in cows), in addition to the prevalence of lactose intolerance. In addition, the vast majority of calcium supplements are calcium citrate or calcium carbonate, most often made from ground-up rock and pressed into tablet form, presenting have solubility problems and difficult with absorption.  By taking these supplements, we could actually be increasing our risk of bone loss, fracture, and even heart disease, the number one cause of death in America today.

Vitamin K2 Critical to Bone Health

Vitamin K, specifically vitamin K2, is thought to be the missing link that allows the body to utilize calcium, as it activates the vascular protein MGP, which inhibits arterial calcification, and it also activates proteins that work to mineralize bones. Vitamin K2 supplementation can reduce the risk for both heart disease and osteoporosis. If vitamin K2 is not present with our calcium supplements, we risk damaging our artery walls and our bones that are not receiving the needed calcium.

Epidemiological studies at the University of Bonn in Germany show an association between a low vitamin K intake and an enhanced bone fracture risk. The Rotterdam Study, which followed about 4,800 individuals over 10 years, showed that individuals who consume the most dietary vitamin K2 experience 50% less arterial calcification and cardiovascular death. Studies in Japan found that vitamin K2 therapy may be a useful method for preventing postmenopausal spinal bone mineral loss. In another Japanese study, Vitamin K2 has effectively and safely increased lumbar bone mineral density in long-term prednisone-treated children who have a high bone turnover. High pharmacological doses of vitamin K2 has been used to prevent further bone mineral loss and fracture risk in osteoporotic patients.

Ideal Sources of Vitamin K2 and Calcium

Choose Whole Foods

Consuming more whole food sources of calcium, vitamin D, and vitamin K2 can allow us to reduce our intake of potentially damaging calcium citrate and/or carbonate supplements. Whole foods are the best sources of essential vitamins of minerals and it comes as no surprise that nature packages complimentary vitamins in foods to enhance absorption. For example, many calcium containing foods often also contain vitamins D, K, and A.

Foods with the highest calcium concentrations include sardines, yogurt, collard greens and fortified orange juice. Vegetables such as cabbage, kale, and broccoli contain calcium but not in significant amounts. Keep in mind, foods high in phytic acid and oxalic acid bind to calcium and can inhibit its absorption. Foods with high levels of oxalic acid include spinach, collard greens, sweet potatoes, rhubarb, and beans. Caffeine and alcohol intake can also interfere with calcium absorption and retention.

Vitamin K Best Sourced from Natto

The Japanese fermented soy bean food known as “natto” contains the MK-7 form of vitamin K2 which is particularly potent and stable in the body. Natto has a sticky texture and a strong flavor. We recently tried adding it to miso soup and it blended in wonderfully. But since natto is fermented using friendly bacteria, it is most beneficial if eaten uncooked.

“Raw Calcium” Whole Food Supplement with Vitamin K2

We have found an excellent whole food plant-based calcium supplement that contains 100mcg of Vitamin K2 in the form of MK-7 harvested from natto and 1,600 IU of RAW Food-Created vitamin D3. It also contains bone-building minerals such as magnesium, boron, silica and vanadium and 22 raw and organically grown fruits and vegetables. The “raw calcium” is sourced from a marine algae known as “algas calcareas” and it is free of commonly-used limestone rock, chalk or animal bone sources of calcium. Available on for $28.59 for 150 capsules. Absorption is best when taking less than 500mg of calcium so dividing doses throughout the day is ideal.
Many factors influence bone mineralization, including protein, salt and vitamin D intake, weight-bearing exercise and exposure to sunlight. Weight bearing exercises such as walking, jogging, weight lifting, stair climbing, and hiking help bones retain and improve density. Vitamin D plays a critical role in bone health because it signals to the intestines to increase the absorption of calcium. Depending on the need, vitamin D can signal absorption increases of up to 80%. The daily recommended dose for those with vitamin D deficiencies or those living in northern latitudes is 4,000 i.u. of vitamin D. It stands to reason that calcium supplementation can be problematic as a stand alone means of preventing osteoporosis and that doses of calcium supplements can be scaled back in favor of increasing whole food forms of calcium, vitamin k2 and vitamin D (either from the sun or supplement form).
Sources: CDC; International Osteoporosis Foundation; Harvard School of Public Health; Office of Dietary Supplements; Osteoporosis Canada; Effects of vitamin K on calcium and bone metabolism by Zittermann, A. Department of Nutrition Science, University of Bonn, Germany.; Inverse correlation between the changes of lumbar bone mineral density and serum undercarboxylated osteocalcin after vitamin K2 (menatetrenone) treatment in children treated with glucocorticoid and alfacalcidol. Inoue T, Sugiyama T, Matsubara T, Kawai S, Furukawa S.Department of Pediatrics, Yamaguchi University School of Medicine, Ube, Japan.; A longitudinal study of the effect of vitamin K2 on bone mineral density in postmenopausal women a comparative study with vitamin D3 and estrogen-progestin therapy. Iwamoto I, Kosha S, Noguchi S, Murakami M, Fujino T, Douchi T, Nagata Y.Department of Obstetrics and Gynecology, Faculty of Medicine, Kagoshima University, Japan.;  Menatetrenone and vitamin D2 with calcium supplements prevent nonvertebral fracture in elderly women with Alzheimer’s disease. Sato Y, Kanoko T, Satoh K, Iwamoto. Department of Neurology, Mitate Hospital, Tagawa; Calcium intake and hip fracture risk in men and women: a meta-analysis of prospective cohort studies and randomized controlled trials.Bischoff-Ferrari HA, Dawson-Hughes B, Baron JA, Burckhardt P, Li R, Spiegelman D, Specker B, Orav JE, Wong JB, Staehelin HB, O’Reilly E, Kiel DP, Willett WC. Department of Nutrition, Harvard School of Public Health, Boston, MA, USA
Image Sources: Asakusa Diary;
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3 responses to “The Importance of Vitamin K2 for Bone and Heart Health

  1. Pingback: Are You Getting Enough Vitamins for Good Bone Health? « THE URBAN CLINIC·

  2. Pingback: Are You Getting Enough Vitamins for Good Bone Health? « THE URBAN CLINIC·

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