Vitamin K2 is a fat-soluble vitamin that is increasingly being shown to offer unique cardiovascular protection. While vitamin K1 or phylloquinone is found in green leafy plants, vitamin K2, aka menaquinone, is found in fermented foods and high fat dairy products from animals that graze predominantly on grass or forage. It may turn out to be one of the more plausible explanations of the French Paradox, much more so than the role of red wine. (The French Paradox is the lower risk of coronary artery disease in a population that eats copious amounts of saturated fat and cholesterol-both of which have already been somewhat debunked as causes of heart disease). Although this may not be a paradox in the first place because saturated fat and cholesterol do not cause heart disease on their own. Sugar and refined carbohydrates of course are a different story.
The first epidemiological signs that vitamin K2 reduces our risk for heart disease came from the Rotterdam Study. The results of this 2004 large-scale nutrition-based study revealed that for every additional 10 micrograms of vitamin K2 an individual consumed, there was a corresponding decreased risk for having a heart attack or coronary event by 9%. Those individuals with the highest vitamin K2 intake had by far the lowest risk and those with the lowest intake had the highest risk. No protective benefits were observed for vitamin K1 however, only for the form of vitamin K2 found in high fat cheeses and other dairy products. There have been few if any dietary components discovered to date that carry greater protective qualities to heart health. The fact that more individuals do not consider vitamin K2 to be an important dietary goal is surprising. Maybe it is because people are still so frightened by saturated fat that they are unwilling to eat the foods that are the richest sources of K2? Even the authors of this study (although it was 2004) complicate matters by stating that while these results are astonishing and even though they observed amazing cardio-protection by those individuals in this 4,800+ sample size, saturated fat and cholesterol cause heart disease so we should be careful in choosing low-fat vitamin K2-rich foods.
Let’s be very clear: this Rotterdam population was not eating low fat cheese! There is almost no vitamin K2 in low fat dairy. It is a fat-soluble vitamin.
A more recent study with a 10 year follow-up showed that those individuals who consumed the most vitamin K2 had the lowest risk of developing metabolic syndrome (obesity, insulin resistance, high triglycerides, and greater risk for coronary artery disease). Maybe we need to start considering high-fat, grass-fed dairy products as part of a heart healthy, weight loss plan?
The role that vitamin K2 plays in the body is very clear: it guides calcification. Calcium added to our skeletal system is generally a good thing but calcium layered on soft tissue such as our tendons, ligaments, or artery linings is not. Much of heart disease is based upon inflammation and calcification, so anything we can do to reduce these processes can be protective. Eating more anti-inflammatory foods is becoming an increasingly important dietary goal for many, but vitamin K2 is hinged to eating unique, often high-fat, fermented foods.
There are numerous sources of the various types of K2. Kimchi (the Korean version of Sauerkraut) and other fermented vegetable dishes are one source, as is Natto, the Japanese fermented soybean product that is pungent, to say the least. Full fat, grass-fed yogurts, kefirs, and cheeses are all phenomenal sources but their low-fat or non fat versions are all but completely missing K2. In our efforts to lower the fat content of an American’s diet for heart health, we may have inadvertently eliminated one of the most beneficial substances we could possible eat for the heart and the rest of our body.
The key is to find only grass-fed versions of fermented dairy products and for those who choose a plant-based source of K2, be sure to source only organic and non-GMO soybean-based Natto.
Geleijnse JM, Vermeer C, Grobbee DE, Schurgers LJ, Knapen MH, van der Meer IM, Hofman A, Witteman JC. Dietary intake of menaquinone is associated with a reduced risk of coronary heart disease: the Rotterdam Study. J Nutr. 2004 Nov;134(11):3100-5.
Veerle Dam et al. Association between vitamin K and the metabolic syndrome: A 10-year follow-up study in adults. The Journal of Clinical Endocrinology & Metabolism 2015 100:6, 2472-2479
John Bagnulo MPH, PhD. Director of Nutrition