Get full access to Outside Learn, our online education hub featuring in-depth nutrition, fitness and adventure courses, and more than 2,000 instructional videos when you sign up for Outside+..
Q: I’ve just started hearing about vitamin K and that it’s the “new” vitamin D. What is vitamin K all about?
-Daniela F., Carson City, Nev.
Vitamin K2 is found in animal fats such as egg yolks, certain cheeses, and butter made from grass-fed animals.
As we have become an increasingly indoor society, we’ve come to recognize the risks of deficiencies in vitamin D (which is produced by sun exposure) and the subsequent need to supplement with vitamin D3. Similarly, vitamin K2 has gone “missing” from many of our diets because its most abundant natural source is chlorophyll.
Chlorophyll is passed through the mammalian digestive tract into the bloodstream and then into the mammary gland. So in the past, humans got this nutrient from drinking cow’s milk. But modern ranchers tend to feed their cows corn, rather than grass, and cows that eat corn do not produce vitamin K2-rich milk.
Vitamin K and D Work Together
Adequate levels of vitamin K2 help prevent a variety of health issues, including diabetes, arthritis, neurodegenerative diseases, cancer, kidney disease, osteoporosis, and infertility. Both D3 and K2 are also involved with calcium metabolism. It’s a good thing scientists discovered the need for vitamin D3 supplements, as they help put calcium into bones, as well as expedite wound healing, improve mood, and lessen pain. However, vitamin D3 without vitamin K2 also places calcium into soft tissue-something you don’t want. This is known as the calcium paradox.
Two of the most disturbing health problems in the modern world are osteoporosis (which can lead to hip fractures and extended, expensive stays in care facilities) and atherosclerosis (a build-up of plaque in the arteries causing high blood pressure and strain on the cardiovascular system). One of the major causes of these diseases is the process of calcium leaving the bone and being deposited in the arteries. Vitamin D3 can help keep calcium in the bone. But you don’t want calcium to build up in your arteries. To prevent this, you need plenty of colorful fruits and vegetables in your diet-their pigments repair the lining of the blood vessels. And you need vitamin K2. It propels calcium into bones and simultaneously inhibits-and in some cases removes-calcium deposition in the arteries.
Vitamin K as a Blood Thinner
You are probably most familiar with the K1 form of vitamin K: phylloquinone. Found mainly in green leafy vegetables, K1 encourages blood clotting. For this reason, people on blood thinners are told to avoid green leafy vegetables.
Vitamin K2, however, is a different form of the vitamin that is known as menaquinone. It is responsible for appropriate calcification and is found in animal fats such as egg yolks, certain cheeses, and butter made from grass-fed animals. You can also find K2 in natto, a traditional Japanese food made from fermented soybean paste. Nattokinase is an enzyme extracted from natto and sold as a supplement.
While vitamin K1 is recycled in the body, making deficiency rare, vitamin K2 is not recycled. Therefore, dietary intake is crucial and K2 deficiency is common, manifesting as osteoporosis, arterial plaque, and dental cavities. In addition to adding some grass-fed dairy products to your diet, it’s safe to take 50-100 mcg of K2 in supplement form (there is no known toxicity for K2).
Want to Learn More About Vitamin K2?
Much of the information for this article comes from the book, Vitamin K2 and the Calcium Paradox, by Kate Rheaume-Bleue, ND. Check it out to delve more deeply into this topic. Besides preventing plaque accumulation and building better bones, adequate K2 in the diet may help prevent wrinkles, reduce the risk for Alzheimer’s and other brain diseases, improve chronic kidney failure, reduce cancer risk, improve fertility, and normalize facial/dental development in utero, according to the latest evidence.