Vitamin K2: The Forgotten Vitamin

You probably haven’t thought much about vitamin K, but did you know this vitamin can improve your health and extend your life?

It is particularly important for strong bones, cancer protection and a reduced risk of heart attacks and strokes. Vitamin K can help to improve the health of your arteries by reducing calcium deposits on artery walls that lead to atherosclerosis (hardened, inflexible arteries). It can also help reduce the risk of kidney stones and bone spurs.

Vitamin K is a fat soluble vitamin; that means it’s in the same family as vitamin A, E and D. There are actually several compounds that go by the name vitamin K and collectively they are called naphthoquinones. The two main subtypes are vitamin K1 and vitamin K2.

Vitamin K1 is abundantly found in green vegetables such as spinach, broccoli and kale. This led many people to assume that it’s easy to get plenty of vitamin K in your diet as long as you eat lots of vegetables. Unfortunately this is not the case because the fiber in vegetables binds tightly with vitamin K1 and makes it very hard to absorb. Also, you need high levels of good bacteria in the gut in order to produce vitamin K2. Many people are missing these bugs due to digestive problems or medication use.

Vitamin K2 is found in animal products such as meat (especially liver), eggs, dairy products (particularly cheese and butter), and fermented soy foods such as natto. Therefore, vitamin K insufficiency is actually a very common problem and may be putting your health at risk.

What are the functions of vitamin K?

Vitamin K helps your body to heal from injuries. One of its main functions is to enable blood clots to form. This is necessary to help prevent you bleeding to death from a minor injury.  Sufficient vitamin K is also necessary for menstruating women, to help prevent excessively heavy bleeding.

Vitamin K also helps to transport calcium around your body to where it is needed. It helps to transport calcium into the bones, therefore reduces the risk of osteoporosis. Vitamin K also helps to remove calcium from places it shouldn’t be, so it reduces the risk of calcification of the arteries and calcified heart valves. Many people are finding out they are low in vitamin D and have started taking a vitamin D supplement. This is a wise decision because vitamin D has so many health benefits. It’s important to balance this with vitamin K2. Anybody with low vitamin D should also be tested for vitamin B12 because these deficiencies often go together.

How would you know if you’re vitamin K deficient?

Mild deficiency generally doesn’t produce any symptoms. People most at risk of vitamin K deficiency are those with malabsorption due to digestive problems (eg. Celiac disease, inflammatory bowel disease), high alcohol consumption, elderly individuals, vegans or anyone suffering with general malnutrition.

The most common symptoms of vitamin K deficiency are:

  • Easy bruising
  • Heavy menstrual bleeding
  • Blood in the urine or stool

If you suffer with any of these conditions it is important to see your doctor for an accurate diagnosis, as these symptoms may be caused by other health problems.

What’s the best way to get more vitamin K?

As I mentioned, vitamin K1 is found abundantly in green leafy vegetables, therefore the following foods are all a good source: Brussels sprouts, kale, broccoli, spinach, chard, collards and parsley. Vitamin K2 is up to 10 times more biologically active in the body than K1. Good sources of it include liver, fermented foods (including sauerkraut), some cheese (particularly aged hard cheese and Swiss cheese) and fermented soy foods such as natto.

Many people don’t typically include a lot of those foods in their diet. If you have osteoporosis, osteopenia, hardened arteries or other symptoms of vitamin K deficiency, you may want to try a supplement.

If you are taking the blood thinning drug warfarin you should not take a vitamin K supplement as it would prevent the warfarin from working. If you are taking a different blood thinning drug (anticoagulant), you should discuss supplementation with your doctor.

The above statements have not been evaluated by the FDA and are not intended to diagnose, treat or cure any disease.

References:
Shearer MJ. The roles of vitamins D and K in bone health and osteoporosis prevention. Proc Nutr Soc. 1997;56(3):915-937.
Olson RE. Vitamin K. In: Shils M, Olson JA, Shike M, Ross AC, eds. Modern Nutrition in Health and Disease. 9th ed. Baltimore: Lippincott Williams & Wilkins; 1999:363-380.
Booth SL. Skeletal functions of vitamin K-dependent proteins: not just for clotting anymore. Nutr Rev. 1997;55(7):282-284
Ferland G. The vitamin K-dependent proteins: an update. Nutr Rev. 1998;56(8):223-230
Booth SL, Suttie JW. Dietary intake and adequacy of vitamin K. J Nutr. 1998;128(5):785-788
Vermeer C, Jie KS, Knapen MH. Role of vitamin K in bone metabolism. Annu Rev Nutr. 1995;15:1-22