Low vitamin K status linked to higher blood pressure, stiffer arteries
The new study, published in the Journal of the American Heart Association, focuses on desphospho‐uncarboxylated matrix Gla protein (dp-ucMGP), which is a biomarker of vitamin K status. Data from 835 Flemish individuals indicated that higher inactive dp-ucMGP was associated with a range of negative cardiovascular measures, such as higher pulse wave velocity (a measure of arterial stiffness) and central pulse pressure.
“Our findings have clinical implications,” wrote the authors. “First, high levels of plasma dp‐ucMGP are a proxy for vitamin K deficiency.” The data suggested that almost 35% of Flemish people may be vitamin K deficient, they added, “which raises the question as to whether the current recommended dietary allowance for vitamin K intake is sufficient to prevent cardiovascular disease.
“Second, vitamin K supplementation reduced aortic pulse wave velocity in healthy postmenopausal women. In a double‐blind, placebo‐controlled trial, healthy postmenopausal women received either placebo (n=124) or menaquinone‐7 (n=120) for 3 years. Compared with placebo, menaquinone‐7 [a form of vitamin K2] decreased dp‐ucMGP by 50%.
“Assuming reversibility, our current findings highlight the protective role of vitamin K to the vascular integrity. Vitamin K has a wide safety range. Sources are leafy vegetables (phylloquinone: vitamin K1), fermented foods (menaquinones: vitamin K2), or dietary supplements.”
The study’s findings were welcomed by Dr. Hogne Vik, Chief Medical Officer of NattoPharma, which supplies the MenaQ7 brand of vitamin K2 for dietary supplements and functional foods.
“This research again confirms a link to vitamin K status and risk of cardiovascular health. NattoPharma's research has shown that vitamin K2 supplementation can halt and even regress progression of arterial stiffness,” said Dr Vik. “This paper recognizes that stiffening and calcification of the large arteries are forerunners of cardiovascular complication, and the mechanism to prevent this is the vitamin K-dependent activation of MGP.
“Importantly, only vitamin K2 intake has been linked to cardiovascular benefit as K2 is the most bioactive and longest-lasting form of vitamin K. Vitamin K1, for example, has not been linked to cardiovascular benefit as K2 seems to be the form of K active outside of the liver for cardiovascular health,” he added.
Vitamin K facts
There are two main forms of vitamin K: phylloquinone (vitamin K1), which is found in green leafy vegetables such as lettuce, broccoli and spinach, and makes up about 90% of the vitamin K in a typical Western diet; and menaquinones (vitamin K2), which make up about 10% of Western vitamin K consumption and can be synthesized in the gut by microflora.
Menaquinones (MK-n: with the n determined by the number of prenyl side chains) can also be found in the diet; MK-4 can be found in animal meat, MK-7, MK-8, and MK-9 are found in fermented food products like cheese, and natto is a rich source of MK-7.
The potential health benefits of the vitamin include cardiovascular and bone health, with some data also supporting a role for prostate health and cognitive benefits.
The wider benefits of vitamin K were also highlighted in a 2009 study by Joyce McCann, PhD, and Bruce Ames, PhD, from Children's Hospital Oakland Research Institute.
Source: Journal of the American Heart Association
2019, Volume 8, Issue 7, e011960. doi: 10.1161/JAHA.119.011960
“Central Hemodynamics in Relation to Circulating Desphospho‐Uncarboxylated Matrix Gla Protein: A Population Study”
Authors: F‐F. Wei et al.