Vitamin K2: Calcium's Not-So Little Helper (Part 2 of 2)

Katarzyna Maresz, Katarzyna Maresz

October 30, 2013

4 Min Read
Vitamin K2: Calcium's Not-So Little Helper (Part 2 of 2)

To read part 1, please click here .

Protecting Heart Health

Adequate intake of vitamin K2 has been shown to lower the risk of vascular damage because it activates Matrix Gla Protein (MGP), which inhibits calcium from depositing in the vessel walls (arterial calcification).

Hence, calcium is available for other multiple roles in the body, leaving the arteries healthy and flexible. However, vitamin K deficiency results in inadequate activation of MGP, which greatly impairs the calcium removal process and increases the risk of blood vessel calcification. Since this process occurs in the vessel wall, it leads to the wall thickening via calcified plaques (i.e., typical atherosclerosis progression), which is associated with higher risk of cardiovascular events.

The population-based Rotterdam study evaluated 4,807 healthy men and women over age 55 and the relationship between dietary intake of vitamin K and aortic calcification, heart disease, and all-cause mortality. The study revealed that high dietary intake of vitamin K2 (at least 32 mcg per day) and not vitamin K1, reduced arterial calcification by 50 percent, cardiovascular death by 50 percent, and all-cause mortality by 25 percent. These findings were supported by another population-based study with 16,000 healthy women (aged 49-70) from the Prospect-EPIC cohort population.

After eight years, the data showed that high intake of natural vitamin K2, but not vitamin K1, helps protect against cardiovascular events; for every 10 mcg of vitamin K2 (in the forms of MK-7, MK-8 and MK-9) consumed, the risk of coronary heart disease was reduced by 9 percent. A study on 564 post-menopausal women also revealed that vitamin K2 intake decreases coronary calcification, whereas vitamin K1 does not.

A study pending publication on 244 postmenopausal women supplemented with 180 mcg of vitamin K2 as MK-7 actually showed a significant improvement in cardiovascular health as measured by ultra-sound and pulse-wave velocity, which are recognized standard measurements for cardiovascular health. In this trial, carotid artery distensibility (i.e., elasticity) the ability for a blood vessel to stretch or dilate was significantly improved over a three-year period as compared to the placebo group. Also, pulse-wave velocity was significantly decreased in the vitamin K2 (MK-7) group, but not the placebo group, demonstrating an increase in the elasticity and reduction in age-related arterial stiffening.

Calcium Connection

Dysfunctional calcium-regulatory proteins such as MGP correlate with the development of arterial calcification. To render these proteins active, a sufficient amount of vitamin K2 has to be present in the body. If at least 32 mcg of vitamin K2 is present in the diet, then the risk for blood vessel calcification and heart problems is significantly lowered and elasticity of the vessel wall is increased. On the contrary, if less vitamin K2 is present in the diet, then cardiovascular problems may arise.

In general, the typical Western diet contains insufficient amounts of vitamin K2 to adequately activate MGP, which means about 30 percent of vitamin K2-activated proteins remain inactive. This amount only increases with age.

Vitamin K, especially as vitamin K2, is nearly non-existent in junk food, and even in a healthy Western diet. The only exception seems to be the Japanese diet, particularly in the portion of the population consuming high quantities of vitamin k-rich foods, such as natto.

It appears that suboptimal vitamin K2 levels in the body may disadvantage the vitamin K2-dependent activation of specific proteins. If these proteins cannot perform their function by keeping calcium in the bones and preventing calcium deposits in soft tissues (e.g. arterial walls) during situations of increased calcium intake, then general health and in particular cardiovascular health may suffer due to an inefficient and misdirected utilization of calcium in the body.

Dietary calcium is linked to many benefits, especially bone health. This is why recommended daily intakes for calcium have been established. Because diets often fall short of these guidelines, in particular in individuals with higher needs (e.g. children, the elderly, and postmenopausal women), dietary supplementation can help address the bodys demands. Although the study outcomes of high calcium consumption are controversial, several studies do suggest caution when it comes to over supplementing, especially since some evidence points to health problems at elevated levels.

This issue could be remedied, however, if the right amount of vitamin K2 is added to a high calcium regimen. Vitamin K2 promotes arterial flexibility by preventing arterial calcium accumulation, which could correct the imbalance of calcium in the body. Thus, calcium in tandem with vitamin K2 may well be the solution for bringing necessary bone benefits while circumventing an increased risk for heart disease.

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