The Critical Importance of Fat Soluble Vitamins – Vitamin K2

A Quick Primer

One of the major benefits of being on a high-fat/ketogenic diet is that the intake of fat-soluble vitamins increases dramatically. Consuming a variety of dietary fats is not just important for creating healthy cells and optimal hormone levels. Fat is also needed for the absorption of fat-soluble vitamins.

What is a fat soluble vitamin? Vitamins are categorized as either fat soluble (vitamins A, D, E and K) or water soluble (vitamins B and C). The distinction between these two types of nutrients is very important. It governs how each one acts inside the body.

Fat soluble vitamins are soluble in lipids (fats). These vitamins are usually absorbed into fat globules (called chylomicrons) that travel through the lymphatic system of the small intestines and into the general blood supply. These fat soluble vitamins, especially vitamins A and E, are subsequently stored in the body’s tissues.

Water soluble vitamins, on the other hand, dissolve in water when they are ingested. Then they go in to the blood stream. The body keeps the amount of water soluble vitamins we need at any one time, and any excess amount is excreted in the urine. Since they can’t be stored, everybody needs to consume a continuous supply of water soluble vitamins in order to stay healthy.

The fact that certain vitamins are retained and kept in storage while others are not gives us a hint regarding their relative importance. With this in mind, our next four blog posts will discuss the importance of the four fat soluble vitamins: A, D, E and K.

With ALL fat soluble vitamins, there is a minimum requirement for the consumption of dietary fat. These levels are necessary to ensure correct amounts of the vitamins in question. Unfortunately, the intake of fat recommended by various first-world government organizations is generally well below what is needed for optimal utilization of fat-soluble vitamins. It is important to note that saturated fat must be consumed in adequate amounts,(and in higher levels than those often recommended), in order to properly provide fat-soluble vitamins to required tissues.

Vitamin K2

logoIt’s not often that we hear anything about a “new” vitamin, at least not one that stands up to its media generated hype. Vitamin K2 has been in our diets for thousands and thousands of years, but with the rise of low-fat and fat phobic diets, it has all but disappeared from our daily food choices.  This lost nutrient disappeared as a result of being mis-identified, and so it was overlooked for almost a century.

Get ready because this powerful nutrient is changing the way we look at everything from diet, to drugs, to dental health … let’s do it!

What is Vitamin K?

Vitamin K is a fat-soluble vitamin that is best known for the important role it plays in blood clotting. However, vitamin K is also absolutely essential to building strong bones and preventing heart disease. Vitamin K also has appears to have potent anti-cancer properties. Vitamin K is sometimes referred to as “the forgotten vitamin” because these major benefits are so often overlooked.

Why were these benefits overlooked?

k2Vitamin K comes in three different forms, vitamin K1, K2 and the synthetically manufactured K3. These variations have drastically different effects on the body. When vitamin K was discovered over 70 years ago, it was assumed that all forms of vitamin K have the same action in the human body. There was no distinction made between the three. This generalization and overemphasis on one form of vitamin K led to a lack of vitamin K2 in our diets. Significantly, it has the most powerful health promoting effects of all three forms.

The Three K’s

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.

Vitamin K2, also called menaquinone, is produced internally by the bacteria that line the gastrointestinal tract. K2 goes straight to blood vessel walls, bones, and tissues other than the liver.  Vitamin K2 can be obtained by consuming full-fat dairy products, certain cheeses and organ meats. Most supplements are based on a fermented form of soy called natto. Please note that there is a strong link between many forms of natural fermentation and the production of vitamin K2. There is a similar connection to the presence of probiotics in the gut.

Vitamin K3, or menadione, is a synthetic form I do not recommend. It’s important to note that toxicity has occurred in infants injected with this synthetic vitamin K3.

The presence of vitamin K1 alone was thought to be sufficient to provide health benefits since the differences between all three forms was not initially understood. That narrowing of emphasis on all these forms coupled with the misguided war on dietary fat and dairy in the 20th century caused a drastic decrease in K2 intake relative to consumption of K1. As we will see later in this blog post, these are two very different vitamins.

What are the differences in benefit between vitamin K1 and K2?

AAEAAQAAAAAAAAL8AAAAJDZjOTAyNDQ4LWVjMmYtNDMzNC1iMDk1LWZiZmZiNjU5ODIxMQAlmost 90% of all vitamin K in the modern diet occurs in the form of K1. Modern technology has allowed its quantification in food for several decades. However, it was only 11 years ago that it became possible to accurately analyze foods for their K2 content. A report by Schurgers et al estimated our vitamin K2 intake in multiple cohort studies.

The first study, called the Rotterdam Study, differentiated between the health benefits of dietary K1 and K2 studied in a group of 4,500 elderly men and women (> 55 years old). The participants’ dietary habits were analyzed using food frequency questionnaires coupled dwith regular medical examinations during a follow-up period of over 10 years. The results were striking. Dietary vitamin K1 intake had no effect on cardiovascular health. However, there was a solid inverse association between K2 intake and several serious circulatory indicators including: the amount of aortic calcification, the incidence of myocardial infarction, and cardiovascular mortality (50% lower in those consuming 45 µg/day of K2 or more). Also all-cause mortality was reduced by 25% where levels of K2 were higher.

At the time of the Rotterdam study, the mechanism causing these outcomes was not understood. This was likely to have been because vitamin K2 is fat soluble, and fat was so strongly believed to promote heart disease. The results caused much consternation in the scientific community. This study was replicated by a different research group, in an independent and much larger group known as the Prospect study. This time, the total number of subjects was above 16,000 and again the observation period was 10 years or more. Just as in the Rotterdam Study – no effect on cardiovascular health by K1 was observed while there were major effects attributed to K2. Because of a much larger sample size than the Rotterdam study, the researchers were even able to calculate that each extra intake of 10 µg/day of K2 resulted in a 9% decreased risk for cardiovascular mortality.

How does Vitamin K2 work?

Vitamin K keeps calcium in the right places.

vitamin_k_mgp_calcificationVitamin K2 helps to prevent hardening of the arteries, which is a common factor in coronary artery disease and heart failure. Research suggests vitamin K2 works by keeping calcium out of your artery linings as well as other body tissues. As discussed above, it is vitamin K2, not K1, which prevents calcification in your coronary arteries. This calcification is commonly referred to as “hardening of the arteries”.

Vitamin K2 Helps Prevent Osteoporosis

The absolute best way to achieve healthy bones is a diet rich in fresh, raw whole foods that maximizes the processing of natural minerals so that your body has the raw materials it needs to do what it was designed to do. Given appropriate levels of these minerals, Vitamin K2 functions as one of the most important nutritional agents 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 clinical studies trials have shown that vitamin K2 entirely reverses bone loss and in some cases actually increases bone mass in people with osteoporosis. A published study by Shiraki and colleagues found that Vitamin K2 effectively prevents fractures and sustains lumbar bone mineral density in osteoporosis.  A study by Knapen found that Vitamin K2 supplementation improves hip bone geometry and bone strength indices in postmenopausal women. A systemic review of multiple clinical trials published in the Journal of the American Medical Association has found that vitamin K2 supplementation reduces bone loss.

Vitamin K Helps Prevent Cancer

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

A study published in September 2003 in the International Journal of Oncology, found that treating lung cancer patients with vitamin K2 slowed the growth of cancer cells, and previous studies have shown benefit in treating leukemia. An August 2003 study published in the Alternative Medicine Review involved 30 patients with a type of liver cancer called hepatocellular carcinoma. They 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, the American Journal of Clinical Nutrition published a study showing that vitamin K2 provides substantial protection against prostate cancer. According to the report, men taking the highest amounts of K2 had about 50 percent less prostate cancer.

How does vitamin K2 protect against cancer?

Vitamin K2 activates a protein called Gas6, which is short for growth arrest sequence 6 protein. It is a powerful regulator of cell growth. This makes vitamin K2’s activation of Gas6 a powerful ally in the fight against cancer, both in its prevention and its treatment. This nutrient can cause cancer cells to die. As well, it can encourage certain types of cancers to turn back into healthy non-cancerous cells.


high_vitamin_k2_intakeVitamin K2 supplementation is very safe for both adults and children. It has no known toxic effects, even at dosages much higher than those recommended in this post. Current research shows that 200 mcg daily is an optimal dose. That is a couple of small softgel s since they generally contain 100 to 120 mcg per capsule. If you are looking for maximal absorption take your K2 with some form of fat, since it is fat soluble. If you are looking for maximal effect, please be sure to take this vital nutrient along with 3000-5000 iu of vitamin D.

Foods Highest in Vitamin K2 include:

  • Natto
  • Hard cheese
  • Soft cheese
  • Egg yolk
  • Butter
  • Chicken liver
  • Salami
  • Chicken breast

Stay tuned for our last post on fat soluble vitamins … VITAMIN E!

3 thoughts on “The Critical Importance of Fat Soluble Vitamins – Vitamin K2

    1. What part of the world do you live in? There are a couple of companies that I support. The most important part is that the manufacturer is GMP certified, and that they source their K2 from natto (MK7).

  1. I found your site searching through Google for some studies to back up something which I recently wrote about. I must that I’m REALLY glad that I found this place! While I’ve only read the K2 article, yet, I do plan on reading through a few more very soon. The way that you breakdown some of the lingo in the studies is great for the general population; something which I really try and love to do myself. Thank you! Keep it up!

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