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10 Important Facts About Vitamin K That You Need to Know

Vitamin K in Natto

Story at-a-glance -

  • Vitamin K is an important fat-soluble vitamin that plays critical roles in protecting your heart, building your bones, optimizing your insulin levels, and helping your blood to clotproperly
  • Vitamin K is an important adjunct to vitamin D, and nearly everyone tested is deficient in both
  • Of the three types of vitamin K, vitamin K2 is the best form to take. The ideal source is fermented foods (like natto),but it must be consumed with fat in order for your body to absorb it
  • Recent research has shown that having adequate vitamin K is important in preventing heart disease, osteoporosis, diabetes, multiple types of cancer, and even Alzheimer’s disease, among others
  • If you have certain health conditions, you should consult your healthcare provider before starting a vitamin K supplement

By Dr. Mercola

Vitamin K is a fat-soluble vitamin that is most well known for the important role it plays in blood clotting. However, vitamin K is also absolutely essential to building strong bones, preventing heart disease, and crucial part ofother bodily processes. In fact, vitamin K is sometimes referred to as "the forgotten vitamin" because its major benefits are often overlooked.

Recent evidence suggestsvitamin K is an important adjunct to vitamin D, and if you are deficient in one, neither works optimally in your body. As you may already know, vitamin D is a key player in your overall health.

According to one of the world's top vitamin K researchers, Dr. Cees Vermeer, just like with vitamin D, nearly everyone is deficient in vitamin K.Most of you get enough K from your diet to maintain adequate blood clotting, but NOT enough to protect you from a variety ofother health problems. In this article, I will discuss 10 important reasons why it's so important to make sure you are consuming enough vitamin K. The following table summarizes potential health problems that can be associated with a vitamin K deficiency.

Arterial calcification, cardiovascular disease and varicose veins Brain health problems, including dementia (the specifics of which are under study)
Osteoporosis Tooth decay
Prostate cancer, lung cancer, liver cancer and leukemia Infectious diseases such as pneumonia

1. Three Types of Vitamin K—Which is Best?

The three types of vitamin K are the following:

  1. Vitamin K1, or phylloquinone, is found naturally in plants, especially green vegetables; K1 goes directly to your liver and helps you maintain healthy blood clotting
  2. Vitamin K2, also called menaquinone, is made by the bacteria that line yourgastrointestinal tract; K2 goes straight to your blood vessel walls, bones, and tissues other than your liver
  3. Vitamin K3, or menadione, is a synthetic form I do not recommend; it's important to note that toxicity has occurred in infants injected withthis syntheticvitamin K3

The vitamin K I recommend for supplementation is vitamin K2, which is natural and not toxic, at even 500 times the RDA. Vitamin K2, which is made in your body and also produced by fermented foods, is a superior form of vitamin K.Increasing your K2 by consuming more fermented foods is the most desirable way to increase your levels. The food highest in natural K2 is natto, which is a form of fermented soybeans consumed in Asia.

2. Vitamin K2 Protects Your Heart

Vitamin K2 helps to prevent hardening of the arteries, which is a common factor in coronary artery disease and heart failure. Research suggests vitamin K2 may help to keep calcium out of your artery linings and other body tissues, where it can causedamage. The latest studies show it's vitamin K2, rather than K1, in concert with vitamin D, that prevents calcification in your coronary arteries, thereby preventing cardiovascular disease.

3. Vitamin K2 Helps Prevent Osteoporosis

The absolute best way to achieve healthy bones is a diet rich in fresh, raw whole foods that maximizes natural minerals so your body has the raw materials it needs to do what it was designed to do.Vitamin K2 is one of the most important nutritional interventions for improving your bone density. It serves as the biological "glue" that helps plug calcium and other important minerals into your bone matrix. There have been some remarkable research studies about the protective effects of vitamin K2 against osteoporosis:

  • A number of Japanese trials have shown that vitamin K2 completely reverses bone loss and in some cases even increases bone mass in people with osteoporosis.
  • The pooled evidence of seven Japanese trials show that vitamin K2 supplementation produces a 60 percent reduction in vertebral fractures and an 80 percent reduction in hip and other non-vertebral fractures.
  • Researchers in the Netherlands showed vitamin K2 is three times more effective than vitamin K1 in raising osteocalcin, which controls the building of bone.

Your bone strength depends on more than just calcium. Your bones are actually composed of more than adozen minerals. If you focus just on calcium, you will likely weaken your bones and increase your risk of osteoporosis, as Dr. Robert Thompson explains in his book The Calcium Lie. It's more likely your body can use calcium correctly if it's plant-derived calcium. Good sources include raw milk from pasture-raised cows (who eat the calcium-rich plants), leafy green vegetables, the pith of citrus fruits, carob, and wheatgrass, to name a few.

4. Vitamin K Helps Prevent Cancer

A number of studies have shown that vitamins K1 and K2 are effective against cancer. Consider the following:

  • One study published in September 2003 in the International Journal of Oncology1, found that treating lung cancer patients with vitamin K2 slowed the growth of cancer cells, and previous studies have shown benefit in treating leukemia. In an August 2003 study published in the Alternative Medicine Review2 involving 30 patients with a type of liver cancer called hepatocellular carcinoma, who took oral vitamin K1, the disease stabilized in six patients; seven patients had a partial response; and seven others had improved liver function.In 15 patients, abnormal prothrombin normalized.
  • In 2008, a German research group3 discovered vitamin K2 provides substantial protection against prostate cancer, one of the most common types of cancer among men in the United States. According to Dr. Vermeer, men taking the highest amounts of K2 had about 50 percent less prostate cancer.

Vitamin K has also been found beneficial in the fight against non-Hodgkin lymphoma, colon, stomach, nasopharynx, and oral cancers.

5. Additional Health Benefits of Vitamin K

As written in the March 2004 Life Extension magazine4, researchers have found many other beneficial effects of vitamin K including:

  • Vitamin K2 deficiency may be a contributing factor to Alzheimer's disease, and vitamin K2 supplementation may help in preventing it
  • Vitamin K2 improves insulin sensitivity; people who get the most vitamin K2 from their foods are about 20 percent less likely to develop type 2 diabetes
  • Topical vitamin K may help to reduce bruising
  • Vitamin K may have antioxidant properties

6. Vitamin K is a Fat-Soluble Vitamin

This is important because dietary fat is necessary for the absorption of this vitamin. Therefore, in order for your body to absorb vitamin K effectively, you need to eat some fat along with it.

7. Food Sources of Vitamin K2

Fermented foods, such as natto, typically have the highest concentration of vitamin K found in the human diet and can provide several milligrams of vitamin K2 on a daily basis. This level far exceeds the amount found in dark green vegetables. Unfortunately, most Americans do not eat many fermented foods. Adding traditionally fermented foods to your diet is a must, and although not widely known, the health benefits of these foods are tremendous.

Precise K2 values for foods are difficult to find. However, I did find a few estimates5 for comparison, which I've listed in the table below. Other foods high in K2 include raw dairy products such ashard and soft cheeses, raw butter, and kefir, and sauerkraut. Realize that the K2 content of pasteurized dairy and products from confined animal feeding operations, which comprise most commercial sources, are NOT high in K2 and should be avoided. Only grass fed animals (not grain fed) will develop naturally high K2 levels.

Food Vitamin K2
Natto 3.5 ounces 1,000 mcg
Whole egg mayonnaise 197 mcg
Miso 10-30 mcg
Lamb or duck 1 cup 6 mcg
Beef liver 1 cup 5 mcg
Dark meat turkey 1 cup 5 mcg
Chicken liver 1 cup 3 mcg

8. Who Needs Vitamin K?

If you or your family has a history of osteoporosis or heart disease, I strongly advise adding vitamin K to your diet. Keep in mind, you'd have to eat more than one pound of collard greens daily to get the necessary amount of vitamin K. Clearly the collard greens and spinach have great nutritional benefits, but if you already have heart disease, a little extra vitamin K would seem a simple bit of insurance to make sure your blood vessels don't calcify. You will also want to consider adding vitamin K to your diet if you do not eat many vegetables or are concerned you are not getting enough vitamin K from your foods, for whatever reason. The following conditions may put you at an increased risk of vitamin K deficiency:

  • Eating a poor or restricted diet
  • Crohn's disease, ulcerative colitis, celiac disease and other conditions that interfere with nutrient absorption
  • Liver disease that interferes with vitamin K storage
  • Taking drugs such as broad-spectrum antibiotics, cholesterol drugs and aspirin

9. How Much Vitamin K2 Should You Consume?

You can obtain all of the vitamin K2 you need (about 200 micrograms) by eating 15 grams of natto daily, which is half an ounce. It's a small amount and very inexpensive, but many Westerners do not enjoy the taste and texture.

If you don't care for the taste of natto, the next best thing is a high-quality K2 supplement. Remember, you must always take your vitamin K supplement with fat since it is fat-soluble and won't be absorbed without it.Although the exact dosing is yet to be determined, Dr. Vermeer recommends between 45 mcg and 185 mcg daily for adults. You must use caution on the higher doses if you take anticoagulants, but if you are generally healthy and not on these types of medications, I suggest 150 mcg daily.

10. Who Should NOT Take Vitamin K?

If you are pregnant or nursing, you should avoid vitamin K2 supplementation higher than the RDA (65 mcg) unless specifically recommended and monitored by your physician. If you have experienced stroke, cardiac arrest, or are prone to blood clotting, you should not take vitamin K2 without first consulting your physician.