Vitamin Spotlight: Vitamin K - Pathway Genomics
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Vitamin Spotlight: Vitamin K

There are a number of vitamins and minerals that are essential for your body to stay healthy. One of them is vitamin K. Here, we’re looking at the essentials of this vitamin, including its benefits and purpose.

What is Vitamin K?

Vitamin K is a group of fat-soluble vitamins that play a crucial role in blood clotting and bone metabolism. There are three forms of vitamin K:

  1. Vitamin K1, which is also known as phylloquinone (the natural version of K1) and phytonadione (the synthetic version)
  2. Vitamin K2, also known as menaquinone
  3. Vitamin K3, also known as menaphthone or menadione

Vitamin K3 is a synthetic form of vitamin K, whereas vitamin K1 and K2 are found naturally in foods. Vitamin K1 makes up 75 to 90% of all vitamin K we consume, but vitamin K2 is also important. Additionally, despite consuming a higher percentage of vitamin K1, it’s poorly absorbed by the body, with less than 10% actually being absorbed.

Because vitamin K is a fat-soluble vitamin, it’s better absorbed when eaten with dietary fats, and K2 is found in more fat-based foods. While some research suggests that K2 is more important to the body than K1, the jury is still out, so it’s best to focus on getting a combination of the two.

What Does Vitamin K Do for the Body?

Vitamin K is important for a number of reasons, including:

  • Blood clotting. Vitamin K was actually named after the first letter of the German word “koagulation” because of its important role in blood coagulation. Like an ambulance, vitamin K responds to injuries, helping regulate normal blood clotting when you bleed externally or internally.
  • Bone health. Vitamin K plays an important role in helping the body use calcium required for bone and tooth development. Additionally, some studies have shown that low levels of vitamin K are linked to higher risks of hip fracture and low bone mineral density. This is why vitamin K is particularly important for elderly adults.
  • Heart health. Vitamin K can help prevent heart disease. By activating a protein that works to prevent calcification of your arteries, vitamin K can help artery walls maintain elasticity.
  • Although more recent, a study has gone so far as to hypothesize that vitamin K plays a role in one’s lifespan. The reasoning is that vitamin K can help prevent heart disease, osteoporosis, diabetes and other diseases due to its ability to active proteins within these conditions.

What Foods Contain Vitamin K?

Vitamin K1 and K2 are each found in different types of foods. Vitamin K1 is produced by plants and is found in many vegetables, with some of the highest levels in kale, collard greens, spinach, turnip greens, broccoli and Brussels sprouts.

Vitamin K2 is found in several different types of foods, including some animal products and fermented foods. Some of the highest levels of this vitamin can be found in pork sausage, hard cheeses, sauerkraut, egg yolks and natto (fermented soybeans).

Vitamin K3 does not naturally occur in any foods, but can be taken as a supplement.

What are the Side Effects of a Vitamin K Deficiency?

Without enough vitamin K, people may experience excessive bleeding when injured, and they’ll be more inclined to easily bruise and experience gastrointestinal bleeding and excessive menstrual bleeding.

How Can I Tell if I’m Deficient in Vitamin K?

Vitamin K deficiency is very rare among healthy adults. However, those with a disease that affects absorption in the digestive tract, such as active celiac disease, cystic fibrosis or Crohn’s disease, may be at risk for a vitamin K deficiency. Additionally, individuals who drink heavily or take the medication warfarin may be at risk for a deficiency.

Even if you think you’re deficient in vitamin K, speak to your doctor before taking a vitamin K supplement. Vitamin K supplements have been shown to interfere with certain medications, which can cause negative side effects and interactions. These medications include several types of antibiotics, phenytoin, warfarin, orlistat, olestra and several cholesterol-lowering medications.

While everyone’s dietary needs are different, the general recommended dietary allowance for vitamin K is 90 micrograms per day for women and 120 micrograms per day for men. This is an easy amount to meet each day if you eat a healthy and well-balanced diet.

Still concerned you may not be getting enough vitamin K or another vitamin? Consider taking a DNA test, such as Pathway Fit®, which looks at which vitamins you may need to optimize. With the guidance of your physician, you can determine an effective diet for you and whether you require any supplements.