Are you getting enough vitamin K2?

Over recent years, experts have shared important information regarding vitamin K2 and its role in prevalent health concerns such as heart disease (due to artery calcification), osteoporosis, cancer, cognition, and rheumatoid arthritis. [1]

Vitamin K is a group of essential, fat-soluble vitamins, of which there are different forms. Many people are familiar with the most popular form, vitamin K1, and its important role in blood clotting. However, vitamin K2 is just as important but lesser-known. Not only that, but vit K2 is associated with misconceptions, even further undermining its importance for our overall health and wellbeing.

Let’s unpack these vitamin K myths. Then, we will discuss how to tell if you get enough K2 and deficiency symptoms in adults, sources and benefits, and where to get vitamin K2.

Myth 1: Vitamins K1 and K2 have similar functions and health benefits

The human body handles vitamins in very different manners, even vitamins from the same group (i.e. vitamins K1 and K2). Interestingly, some experts state that vitamin K2 could be more effective than vitamin K1 in terms of supporting blood clotting. We know that vitamin K1 is used by the liver to create proteins required for blood coagulation. However, vit K2 reaches other tissues where it can support and perform more functions, resulting in a wide range of health benefits.

Myth 2: as long as you are eating lots of leafy green vegetables, you needn’t worry about vitamin K2 supplementation, as the body converts vitamin K1 into K2.

This point is unbacked and meritless. Firstly, vitamins K1 and K2 come from different sources, and your body cannot convert K1 into K2 effectively enough to achieve optimum levels. Vitamin K1 (also known as phylloquinone) is sourced via leafy green veggies such as broccoli, Brussels sprouts, mustard greens, spinach, and kale. You can also find K1 in certain fruits and grains. Foods high in vitamin K2 (menaquinone) include fermented foods and animal-based products.

Vitamin K2 highlights

  1. Vitamin K2 exists in other forms from MK4 to MK13. M stands for menaquinone, and the number tells you how many side-chains are attached to the molecule.
  2. MK4 is found in animal-based foods like grass-fed meat, dairy, and eggs.
  3. MK7 is found in fermented foods such as sauerkraut and cheese, with natto (fermented soybeans) being the best source of MK7.
MK4 and MK7 are metabolised in very different ways, due to their bioavailability and benefits. For example, MK7 remains in the body for longer than MK4 does. We will leave these fascinating differences for another blog, as here we want to focus on the signs of vit K2 deficiency, and the subsequent health risks associated with such deficiency.

Signs of Vitamin K2 Deficiency

Most people are deficient in vitamin K2. However, K2 deficiency signs are hard to identify. This is because K2 deficiency doesn’t cause painful or glaring symptoms until the deficiency progresses (when it then becomes dangerous). However, it helps to understand the factors that make you deficient and the conditions that can develop as a result. That way, you can more accurately gauge your body’s K2 status.

Are you at risk? Check off these vitamin K2 deficiency risk factors:

  1. Your diet lacks K2-rich foods: most of us don’t consume enough K2 food sources.
  2. You use anticoagulants excessively: heart patients are often prescribed with anticoagulant drugs such as warfarin (Coumadin). These drugs prevent the synthesis of vitamin K-dependent proteins responsible for blood clotting.
  3. You use antibiotics frequently: antibiotics destroy the healthy bacteria in your gut. These bacteria help in the production of vitamin K2 and also help with its absorption.
  4. You have nutrient absorption issues: gastrointestinal issues such as Crohn’s disease, celiac disease, ulcerative colitis, abdominal surgery, and gut dysbiosis (overgrowth of bad bacteria) can lead to K2 deficiency. This is because such issues can hinder it's absorption and other crucial nutrients.
  5. You have a dysfunctional liver: liver diseases such as cirrhosis can interfere with the synthesis of vitamin K-dependent factors.
  6. You use statins: studies show that cholesterol-lowering drugs (statins) inhibit vitamin K2 absorption. This is because statins inhibit the enzyme that helps your liver to create cholesterol. However, this enzyme is at the base of a biochemical chain reaction that produces other compounds such as vitamin D, stress hormones, CoQ10, bile acid, and K2.
  7. You eat a low-fat diet: K2 is a fat-soluble vitamin, meaning that it will struggle to absorb into the body if you eat a low-fat diet.

Liposomal Vitamin D3 + K2

Health conditions associated with vitamin K2 deficiency

1. Osteoporosis and increased risk of bone fractures

Calcium and vitamin D, the two most commonly-known “bone vitamins” are not enough to prevent osteoporosis on their own if your vitamin K2 levels are lacking. In fact, vitamin D (crucial for calcium absorption) works seamlessly with K2.

It moves calcium to the areas where it is needed, and out of the areas where it is not.

There are health risks associated with calcium ingestion, including heart attack, stroke, kidney stones, muscle spasms, and constipation. However, these risks don’t arise due to the calcium itself, but when you don’t have a healthy balance between calcium and other key nutrients such as vitamin D3, magnesium, and vitamin K2. You see, these nutrients help the body to absorb calcium efficiently. Otherwise, calcium ends up gathering in unwanted places, causing complications.

Research shows that a combination of calcium, vitamin K2, and vitamin D3 improves bone strength and reduces the risk of fractures. Interestingly, K2 is used as an osteoporosis treatment in Japan. Studies also show that it can help to lower bone loss in premenstrual women. One particular study showed that K2 supplementation improved bone mineral content, bone mineral density, and bone strength in healthy post-menstrual women without osteoporosis. [2]

How does vitamin K2 influence bone health?

Vitamin K2 activates a special protein called osteocalcin that is produced by bone-forming cells called osteoblasts. Osteocalcin binds with the calcium circulating in the bloodstream and delivers it to the bone matrix where it helps to build strong and healthy bones.

2. Increased risk of heart attack and stroke

Vitamin K2 deficiency has a surprising and concerning effect on your heart health. This is because K2 activates Matrix GLa Protein (MGP), which attaches to calcium and prevents it from reaching soft tissues such as blood vessels and cartilage. MGP is one of the strongest inhibitors of calcification of the arteries, a serious risk factor for coronary heart disease. When you are deficient in vitamin K2, the function of MGP is impaired. This leads to excessive and abnormal accumulation of calcium in your arteries and other soft tissues where calcium should not gather. A well-known Rotterdam study (among many) found that increasing vitamin K2 intake lowers the risk of arterial calcification and death from heart disease. [3] [4]

3. Cancer

Research shows that vitamin K2 has anti-cancer effects on cancer cell lines via various mechanisms. K2 is believed to have anti-carcinogenic effects due to its ability to regulate gene expression. It has been shown to:
  • Induce apoptosis (cell death) and degradation in leukemia cells [5]
  • Lower risk of advanced prostate cancer (whereas higher intake of vitamin K1 was not associated with this benefit). [6]
  • Suppress the recurrence of liver cancer [7]

4. Type 2 Diabetes

Observational studies and clinical trials have concluded that vitamin K2 can reduce the risk of Type 2 Diabetes. A 2018 review of existing studies suggested that K2 improved insulin sensitivity through various mechanisms, including osteocalcin metabolism (osteocalcin works as an endocrine hormone to improve insulin sensitivity). It was also proved to lower lipids and reduce inflammation. [8]

5. Rheumatoid Arthritis

It has been found that vitamin K2 supplementation, in the form of MK7, is effective in the treatment of rheumatoid arthritis. While MK4 has also been found to reduce disease activity in rheumatoid arthritis patients, it is less bioavailable than MK7. A study showed that MK7 decreased the levels of clinical and biochemical markers of inflammation like ESR, C-reactive protein, and matrix metalloproteinase (MMP-3). [9]

Plus, MK8 also increased osteocalcin levels, a protein that requires K2 in order to carry out its job. As we’ve discovered earlier in the blog, osteocalcin improves bone health by integrating calcium into the bone matrix.

Improving your levels of vitamin K2

Now we get to the practical part: how to get enough vitamin K2. The reality is, even if you are eating a healthy diet, you may still be deficient in K2 if you are not including fermented and animal-based foods. The best Vitamin K2 natural source is natto, providing 250mcg per ounce. While natto (fermented soy) is popular in Eastern Japan, its pungent aroma and flavor make it less popular in other parts of the world. However, egg yolk, beef, goose, liver patty, and cheese are also great sources of K2 and may be more readily available to you.

If the Vitamin K2 rich foods list is simply too difficult or pricey to source, you can always take a high-quality vitamin K2 supplement to achieve optimum levels. The great news is that there is no known toxicity linked with high doses of K2, so you cannot harm yourself via supplementation. However, it’s very important to consult your doctor before you take any new supplement. Even if a supplement is deemed to be safe and zero-risk, your health status and other medications may cause complications.

  1. Gerry Kurt Schwalfenberg. Vitamins K1 and K2: The Emerging Group of Vitamins Required for Human Health. J Nutr Metab. 2017.
  2. Knapen et al. Three-year low-dose menaquinone-7 supplementation helps decrease bone loss in healthy postmenopausal women. Osteoporos Int. 2013
  3. Johanna M. Geleijnse et al. Dietary Intake of Menaquinone Is Associated with a Reduced Risk of Coronary Heart Disease: The Rotterdam Study. The Journal of Nutrition. 2004.
  4. G.C. Gast et al. A High Menaquinone Intake Reduces the Incidence of Coronary Heart Disease. Nutr. Metab. Cardiovasc. Dis. 2009.
  5. Yokoyama et al. Vitamin K2 induces autophagy and apoptosis simultaneously in leukemia cells. Autophagy. 2008
  6. Nimptsch et al. Dietary intake of vitamin K and risk of prostate cancer in the Heidelberg cohort of the European Prospective Investigation into Cancer and Nutrition (EPIC-Heidelberg). Am J Clin Nutr. 2008
  7. Ishizuka et al. Effect of menatetrenone, a vitamin k2 analog, on recurrence of hepatocellular carcinoma after surgical resection: a prospective randomized controlled trial. Anticancer Res. 2012
  8. MS Abdel-Rahman et al. Menaquinone-7 as a novel pharmacological therapy in the treatment of rheumatoid arthritis: A clinical study. Eur J Pharmacol. 2015
  9. Yan Li et al. Effect of vitamin K2 on type 2 diabetes mellitus: A review. Diabetes Research and Clinical Practice. 2018.