Can Anything Cure Vascular Calcification?
Vitamin K's Role in Stopping and Reversing Calcification
Oct 5, 2009
Vascular calcification can occur as an effect of ageing or disease, such as kidney disease or diabetes, or it can occur as a consequence of blood-thinning treatment, such as warfarin. For many years the build-up of calcium in the body was thought to be an irreversible process, but new research has shown that the calcification is an actively regulated process, so it may be preventable or even reversible.
Why Does Calcium Build Up in the Blood Vessels and Tissues?
The probable cause of vascular calcification is still being investigated, but it appears that two proteins – matrix Gla (MGP) and osteopontin (OPN) – play a part.
Researchers have been able to study the process by altering the levels of these proteins within rats, causing fairly rapid death simply by depriving them completely of MGP. Scientists have also deliberately induced calcification in rats by feeding them high levels of warfarin, the blood-thinning drug, in order to test a possible cure.
The Blood-thinning Connection
One study, by the Cardiovascular Research Institute (CARIM) and VitaK, Maastricht University in 2007 (1) found that high-dose vitamin K not only blocked new arterial calcium build-up due to warfarin, but also reduced existing levels.
The vitamin K treatment only worked at high doses. Four groups of rats were subjected to warfarin, then three groups were taken off the drug. Those on no vitamin K or low-dose vitamin K continued to suffer from rising levels of calcification, but those on high-dose vitamin K treatment saw calcification decrease by over 37 per cent within only 6 weeks. The vitamin actually reversed the process.
In another study of 4,500 elderly patients, scientists established an inverse relationship between dietary intake of menaquinone (synthetic vitamin K) and aortic calcification, myocardial infarction, and sudden cardiovascular death. (2)
Interestingly, experiments using samples of healthy and diseased aorta have shown high tissue concentration of vitamin K2 in the heathy aorta, but no K1; and no K1 or K2 in the samples of diseased aorta.
How Does Vitamin K Stop Calcification?
Matrix Gla protein (MGP) is a protein that prevents vascular calcification – and it is only activated in the presence of vitamin K. (MGP must be carboxylated to become active, and vitamin K is a cofactor for carboxylation.) There is so much calcium and phosphate circulating in the body, that without the inhibiting action of MGP, calcification occurs after around six weeks.
As anticoagulant drugs such as warfarin interfere with vitamin K, they block MGP function, and so induce calcification.
Should I Take Vitamin K Supplements?
Research suggest that menaquinone-7 (MK-7) has a much longer serum half-life than phylloquinone (vitamin K1) or MK-4, with better bioavailability. This means that regular nutritional doses (50–150ug/da) may lead to accumulation levels in the circulation and tissues that would only be reached with far higher doses of K1 or MK-4. (5) The best source of natural vitamin K2 is Natto, a Japanese fermented food. Other forms of fermented food such as cheeses and curd also contain MK-7, but in much lower quantities. Green leafy vegetables – such as kale, lettuce, spinach and broccoli – contain the highest content of K1, and account for most of the Western intake of this vitamin, followed by vegetable oils, such as soybean, olive oil and canola.
Meat, fish, dairy products and eggs contain both K1 and MK-4; this is especially concentrated in butter, egg yolk, and goose liver. (6)
In Western diets K1 makes up around 80 per cent of vitamin K intake, although research suggests that at least 50 per cent should be K2, and that supplementation of MK-7 may be desirable. One study found that a pharmacological dose of K1 (1mg/day for 3 years, co-administered with minerals and vitamin D) had beneficial effects on the elastic properties of the arterial vessel wall.
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REFERENCES
- Schurgers et al, April 1, 2007 (volume 109, number 7) issue of Blood (the journal of the American Society of Hematology)
- Geleijnse JM, Vermeer C, Grobbee DL et al. Dietary intake of menaquinone is associated with a reduced risk of coronary heart disease: the Rotterdam study. J Nutr. 2004; 134:3100-5.
- Braam LA, Hoeks AP, Brouns F et al. Beneficial effects of vitamins D and K on the elastic properties of the vessel wall in postmenopausal women: a follow-up study. Thromb Haemost. 2004; 91:373-80.
- Vitamin K2 and Arterial Calcification", Anne Bjornebye Vik, Norway; AgroFood Industry High-Tech; Nove/Dec 2008, Vol 19, no.6
- Ibid.
- Ibid.
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