Special K


Q.I recently heard vitamin K referred to as the “new” vitamin D. What is vitamin K all about?

A. 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).

Modern ranchers tend to feed their cows corn rather than grass, and cows that eat corn do not produce vitamin K2-rich milk.

“Our bodies do not make enough K2 and we can’t get enough in our diet.”

Vitamin K2 deficiency is common, manifesting as osteoporosis, arterial plaque, and dental cavities.

Vitamin K2: Where Heart and Bone Health Meet


Heart and bone health may seem like two different issues, but they’re intimately connected. Studies following nearly 32,000 people found that undetected heart disease multiplies the odds of bone loss and fractures sixfold, and low bone mass increases risk of stroke and heart attack. How so?

Both depend upon calcium getting to the right place: into bones and away from arteries, where deposits of the mineral can be deadly. Vitamin K2, often in short supply, is essential for calcium to hit its mark. “K2 is like an usher in a theater,” says Dennis Goodman, MD, a board-certified cardiologist, director of integrative medicine at NYU Langone Medical Center, and author of Vitamin K2: The Missing Nutrient for Heart and Bone Health; “It helps calcium bind to the bone mineral matrix, keeping it away from blood vessels.” Vitamin K2 is not well known, and should not be confused with vitamin K1, which is plentiful in leafy greens and plays a role in blood clotting.

“Our bodies do not make enough K2 and we can’t get enough in our diet,” says Goodman. Natto, a popular fermented soy food in the Japanese diet, is the only rich food source, with about 1,100 mcg per 3.5-ounce serving. But with a Western diet, a minimum daily beneficial amount of 45 mcg would require eating 8 pounds of beef or drinking 1.32 gallons of milk.

What to do: Goodman recommends taking up to 180 mcg daily of a special form of K2, called MK-7, “menaquinone-7,” or a patented form, “MenaQ7.” In addition to maintaining healthy bones, he says, “You can be preventing or at least retarding calcification of blood vessels.”

—Vera Tweed

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