Vitamin K Supplements
We had a question this morning about Vitamin K supplements. The writer asked for information on vitamin K-2 (supplementation from MK-7), along with calcium and vitamin D for bone health, and wanted to know about the form of vitamin K used in Cooper Complete Original multivitamin and mineral formulations.
Vitamin K is an essential nutrient the liver uses to form proteins that promote blood clotting (and prevent abnormal bleeding). There are three basic forms of vitamin K:
- Vitamin K1 (which includes phytonadione, the form in our multivitamin) is a natural nutrient found in green leafy vegetables, and in smaller amounts, some oils (oil, soybean and canola).
- Vitamin K2 (menaquinones or MKs) include MK4 which is found in meats and dairy products. MK7 is found in some fermented foods, like cheese. This form of K is also found in a Japanese soy product called “natto”. (There’s a website where you can purchase “nattomoto powder” to use with soybeans to make natto. Some say it smells strong, pungent and cheesy, and others say it doesn’t have a lot of smell.)
- Vitamin K3 (menadione) is a man-made form of vitamin K. This form isn’t sold as a supplement for humans, ut is sometimes used in feed for life stock.
Healthy adults eating plenty of leafy green vegetables typically get all the vitamin K they need through their diet. Food provides the body with about half the normal supply of the vitamin needed, and intestinal bacteria produces the rest.
A deficiency can occur in individuals who are on antibiotics for extended periods, have liver damage, or intestinal disorders such as celiac disease. Alcoholism can also contribute to a vitamin K deficiency.
In humans, vitamin K supplements may increase bone mineral density and bone strength. The majority of studies have been conducted on patients in Japan using the menatetrenone form (vitamin K2) of vitamin K as fermented soybeans (Natto) are part of breakfast for many Japanese. Epidemiological studies suggest that decreased vitamin K intake is associated with increased risk of hip fracture, but not decreased bone density, although the association between low intakes of vitamin K and decreased bone density was seen in women in some studies. More research is needed on the potential impact of vitamin K on bone health. We also need research on the subject in the US – with the Japanese studies we don’t know what other foods or lifestyle habits might be different than those of the typical American and yet affect the outcome of the studies.
With its role in blood clotting, consumption of vitamin K is a major issue for individuals on Warfarin (blood thinners), and has to be closely watched as increases in vitamin K make warfarin less effective. For this reason, the Basic One multivitamin and mineral formulations do not contain vitamin K.
It appears that consumption of vitamin K2 (through food or supplementation) can last days longer than vitamin K1, the form found in plants and plant-based supplements, so keep this in mind if you decide to add vitamin K2 to your diet or supplement regimen.