Sense and Nonsense of Dietary Supplements

Scientific evaluation of Cardiovascular health benefits of dietary supplements

Vitamin K

Vitamin K2

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In General three types of vitamin K are defined: Vitamin K1, K2 and K3. Vitamin K1 is most commonly known and has an important role in blood coagulation (Clotting). Just recently the health benefits of Vitamin K2 have been elucidated. Vitamin K2 is also known as menachinone, menaquinone, MK-4, MK-7 and MK-9. It has an important role in bone mineralization, arterial calcification, calcification of the heart valves tissue repair and according to a recent study also in insulin response. Its biological role is to help store calcium into the proper areas in your body, such as your bones and teeth. It also plays a role in removing calcium from areas where it shouldn't be. This is confirmed by recent studies showing that anti-coagulant medication (coumarin derivates) which inhibit vitamin K function lead to an increase in osteoporosis and artery calcification (1-3). Vitamin K3, or menadione, is a synthetic form which is not recommend. Toxicity has occurred in infants injected with this synthetic vitamin K3.


Vitamin K1

There are no indications that vitamin K1 supplements provide health benefits for healthy individuals, provided adequate amounts of vegetables are consumed on daily basis ( 4 ). Since vitamin K promotes coagulation and counteracts the effects the most commonly used of anti-coagulants (coumarin derivates, like acenocoumarol, fenprocoumon en warfarine), vitamin K1 supplements should be avoided by individuals with increased risk of cardiovascular disease.


Vitamin K2
Vitamin K2 helps to reduce calcification of the arteries and heart valves. Two large Dutch studies have investigated this phenomenon.

  • A study in 4,807 elder men and women, published in 2004 in the Journal of Nutrition showed that in the group with a high dietary intake of vitamin K2 had 57% less myocardial infarctions, 52% less calcification of the aorta and 26% less overall mortality compared to the group with al low dietary intake of vitamin K2 ( 4 ).
  • After 8 years and 480 cardiovascular events, the cohort study Prospect EPIC in 16,057 women aged 49-70, showed that each increase in dietary intake of vitamin K2 by 10 microgram resulted in a risk reduction of 9% ( 5 ).

At  Geneva’s Vitafoods 2012 , Dr. Cees Vermeer, Principal Investigator at VitaK laboratory at Maastricht University, has presented data showing significant benefits for improved bone strength and prevention of cardiovascular aging with daily supplementation of the vitamin K2 supplement MenaQ7 . read more

In this long-term study, 244 healthy postmenopausal women received daily 180 µg vitamin K2 from MenaQ7 or a placebo for 3 years. The clinical measurements included bone mineral density, bone strength, vascular characteristics by ultrasound and Pulse-Wave Velocity , the latter evaluating age-related stiffening of blood vessels. MenaQ7 supplementation provided a statistically significant protection of the most vulnerable bone structures i.e. vertebrae and the hip. The MenaQ7 trial showed substantial benefits in preventing age-related stiffening of arteries resulting in increase of the Pulse Wave Velocity in the placebo group, but not in the MenaQ7-group. Most remarkably, MenaQ7 not only prevented stiffening, it also resulted in an unprecedented statistically significant improvement of vascular elasticity both measured with ultrasound techniques and Pulse Wave Velocity.

Several other well-designed clinical trials showed that vitamin K2 helps to reduce osteoporosis ( 5-10 ). In addition, there are indications that vitamin K2 helps to improve insulin response. However, this is not yet substantiated by large clinical trials ( 11 ).

Conclusion
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Daily supplementation with vitamin K2 is recommended to reduce the risk of cardiovascular disease. Vitamin K1 supplementation is not recommended, except for neonates up to 3 months of age.

 

Accepted EFSA Claims

  • Vitamin K contributes to normal blood clotting
  • Vitamin K contributes to the maintenance of normal bones
Names: Vitamin K, Vitamin K1(fyllochinon, fylloquinon, fytomenadion), Vitamin K2 (menachinon, menaquinon, abbreviated to MK), MK-4, MK-7, MK-9, Vitamine K3 (menadion)
Diseases:     Cardiovascular, diseases, acute myocardial infarction, stroke, osteoporosis, diabetes

Reference List

  1. Gage BF et al. , Risk of osteoporotic fracture in elderly patients taking warfarin: results from the National Registry of Atrial Fibrillation 2. Archives of internal medicine 166 , 241-6 (Jan 23, 2006).
  2. Schurgers LJ et al. , Oral anticoagulant treatment: friend or foe in cardiovascular disease? Blood 104 , 3231-2 (Nov 15, 2004).
  3. Spronk HM et al. , Tissue-specific utilization of menaquinone-4 results in the prevention of arterial calcification in warfarin-treated rats. Journal of vascular research 40 , 531-7 (Nov-Dec, 2003).
  4. Geleijnse JM et al. , Dietary intake of menaquinone is associated with a reduced risk of coronary heart disease: the Rotterdam Study. The Journal of nutrition 134 , 3100-5 (Nov, 2004).
  5. Gast GC et al. , A high menaquinone intake reduces the incidence of coronary heart disease. Nutrition, metabolism, and cardiovascular diseases : NMCD 19 , 504-10 (Sep, 2009).
  6. Sato Y et al. , The prevention of hip fracture with menatetrenone and risedronate plus calcium supplementation in elderly patients with Alzheimer disease: a randomized controlled trial. The Kurume medical journal 57 , 117-24 (2011).
  7. Binkley N et al. , Vitamin K treatment reduces undercarboxylated osteocalcin but does not alter bone turnover, density, or geometry in healthy postmenopausal North American women. Journal of bone and mineral research : the official journal of the American Society for Bone and Mineral Research 24 , 983-91 (Jun, 2009).
  8. Vermeer C et al. , Beyond deficiency: potential benefits of increased intakes of vitamin K for bone and vascular health. European journal of nutrition 43 , 325-35 (Dec, 2004).
  9. Cranenburg EC et al. , Vitamin K: the coagulation vitamin that became omnipotent. Thrombosis and haemostasis 98 , 120-5 (Jul, 2007).
  10. Beulens JW et al. , High dietary menaquinone intake is associated with reduced coronary calcification. Atherosclerosis 203 , 489-93 (Apr, 2009).
  11. Choi HJ et al. , Vitamin K2 supplementation improves insulin sensitivity via osteocalcin metabolism: a placebo-controlled trial. Diabetes care 34 , e147 (Sep, 2011).

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