It was a 16th century English physician by the name of Thomas Sydenham who is credited with the saying, “A man is as old as his arteries.” Five centuries later and the adage still rings true. The age of our arteries, or our vascular age, can be a significant factor in determining how long we will live. However, our scientific understanding of vascular age has grown substantially compared to five centuries ago. Cardiologists are now able to better determine the health of our blood vessels through measurements of blood pressure, cholesterol, triglycerides, and arterial calcification.
Arterial calcification is the deposition of calcium within the arterial linings, literally turning arteries into bone. The deposits result in a thickening of the arterial walls, which robs arteries of flexibility and elasticity. They also contribute to the accumulation of arterial plaque structure with fatty deposits and cholesterol, which culminates in fatty streaks and eventually, atherosclerosis. Recently, cardiologists have also discovered that arterial calcification is often accompanied by the weakening of bones. The relationship between the calcification of blood vessels and the decalcification of bones has its roots in a protein known as Matrix Gla (MGP).
MGP is a vitamin K-dependent protein that acts as an arterial calcification inhibitor and could play a critical role for improving vascular age (1). This protein binds calcium ions, thereby promoting their proper biological activity. Vitamin K is necessary for MGP to function because it acts as a cofactor for the γ-carboxylation of the protein. Notably, the drug warfarin being a vitamin K antagonist is long known to cause arterial calcification in rats (1,2). In contrast, a diet high in vitamin K inhibited arterial calcification and helped preserve arterial elasticity in warfarin-treated rats (1,2). However, caution should be exercised before combining vitamin K with warfarin and patients should always discuss supplementation or changes of diet with their doctors.
K1 versus K2
Vitamin K is a fat-soluble vitamin existing in two naturally occurring forms: vitamin K1 (phylloquinone) and vitamin K2 (menaquinone). Vitamin K1 is synthesized in plants and bacteria and can be converted into vitamin K2. A third, synthetic form also exists and is known as vitamin K3 (menadione), which can be toxic unlike the natural forms. The primary function of vitamin K is in a complex pathway involved in blood coagulation. Specifically, vitamin K is required for an enzyme that catalyzes the carboxylation of glutamic acid, forming γ-carboxyglutamate, a necessary amino acid for calcium binding and initiation of the blood clotting process. Other functions include bone mineralization and cellular growth.
Recent research suggests vitamin K1 and K2 should be appreciated as separate nutrients. Unlike vitamin K1, vitamin K2 is needed to activate osteocalcin, a bone-building hormone that is responsible for the clearance of calcium from arteries and shuttling it for the purposes of bone mineralization (3,6), thereby removing excess calcium otherwise available for arterial calcification.Unfortunately, a substantial portion of Americans are obtaining a suboptimal amount of vitamin K, which is inadequate to meet the essential γ-carboxylation required for vitamin K-dependent functions (3-5, 7). Furthermore, low plasma levels of K2 do not maximize carboxylation of osteocalcin (3,6). In one prospective, population-based study, scientists examined the relationship between dietary intake of vitamin K1 and vitamin K2 and its relationship to arterial calcification (6). The study found a strong inverse relationship between vitamin K2 and arterial calcification, while vitamin K1 was not related to any specific outcome. These conclusions remained after adjusting for BMI, smoking, education, diabetes, alcohol intake, and dietary factors. Overall, the results suggest that high vitamin K2 intake may be an important strategy for helping to preserve arteries elasticity.
The RDA for vitamin K is 120 μg/day and 90 μg/day for adult men and women, respectively. Good dietary sources of vitamin K1 include green leafy vegetables (kale, spinach, collards, and lettuce) and some vegetable oils. In contrast, dietary sources of vitamin K2 are mainly eggs, meat, and cheese. In fact, it is hypothesized that vitamin K2 may account for the reduced arterial calcification in France and Mediterranean countries because of their high cheese consumption.
Like other fat-soluble vitamins, a severe deficiency of vitamin K in westernized societies usually only occurs in individuals with genetic malabsorption syndromes (with the one exception being individuals who are on anti-coagulants such as coumadin). However, one study reported that only 17 percent and 27 percent of men and women in Ireland met the current RDA goals (5), while an evaluation of vitamin K intake in America suggested that the average intake was below the RDA.
Daily supplementation with vitamin K2 offers a convenient way of obtaining the protective benefits of this critical nutrient. Ageless Essentials Daily Pack provides a total of 80 μg/day of vitamin K2 and is divided into two doses, one taken in the morning and one in the evening. The product also combines the vitamin with other complementary nutrients for cardiovascular and bone health (calcium and vitamin D). Along with proper diet and exercise, the combination represents a powerful strategy for supporting stronger bones while keeping arteries more flexible, elastic, and youthful.
After all, we’re only as old as our arteries.
- Shea MK et al. Vitamin K supplementation and progression of coronary artery calcium in older men and women. Am J Clin Nutr 2009;89:1799-807.
- Price PA et al. Warfarin causes rapid calcification of the elastic lamellae in rat arteries and heart valves. Arterioscler Throm Vasc Biol 1998;18:1400-7.
- Booth SL. Roles for vitamin K beyond coagulation. Annu Rev Nutr 209;29:89-110.
- Booth SL, Pennington JA, Sadowski JA. Food sources and dietary intakes of vitamin K-1 (phylloquinone) in the American diet: data from the FDA Total Diet Study. J Am Diet Assoc 1996;96:149-54.
- Duggan P et al. Phylloquinone (vitamin K1) intakes and food sources in 18-64-year-old Irish adults. Br J Nutr 2004;92:151-8.
- Geleijnse JM et al. Dietary Intake of Menaquinone is associated with a Reduced risk of coronary heart disease: The Rotterdam Study. J Nutr 2004;234:3100-05.
- McCann JC, Ames BN. Vitamin K, an example of triage theory: is micronutrient inadequacy linked to diseases of aging? Am J Clin Nutr 2009;90:889-907.