Vitamin K: Fat-Soluble Vitamin Deficiency & Toxicity Symptoms

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  • 0:02 Vitamin K
  • 0:35 Deficiency
  • 2:15 Sources
  • 3:30 Toxicity
  • 4:18 Lesson Summary
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Lesson Transcript
Instructor: Rebecca Gillaspy

Dr. Gillaspy has taught health science at University of Phoenix and Ashford University and has a degree from Palmer College of Chiropractic.

Vitamin K is a vitamin needed for blood clotting and bone health. Learn why bleeding and bruising increase in a person with a vitamin K deficiency and why deficiency can increase risk of osteoporosis. Also learn about risks involving overconsumption.

Vitamin K

If a pipe in your house breaks, you call a plumber to patch the leak and stop the flow of water. If your finger gets a cut, your body calls on vitamin K, a fat-soluble vitamin needed to produce blood clotting factors to help patch the leak and stop the flow of blood. So, what if your body does not have enough vitamin K to make the needed clotting factors? Will the bleeding stop? In this lesson, we will answer these questions and also explore what can happen if there is too much vitamin K in your body.


We see that vitamin K is important for blood clotting. In fact, it might help you recall this function if you think of vitamin K as the 'blood klotting vitamin.' So, you can imagine if you have a vitamin K deficiency, you could experience increased bleeding and easy bruising. In fact, if you did not have any vitamin K in your body, even a small cut on your finger would continue to bleed with no end in sight.

This is how the rat poison warfarin works. Warfarin is an anticoagulant, which means it prevents blood clotting. In fact, the term literally translates into, 'against blood clots.'

It does this by prohibiting the activation of vitamin K. When a rat eats the poison, the next little bump or bruise it gets causes uncontrollable bleeding and eventually death. Now, you may have heard of Warfarin before because it is used in health care as a way to prevent blood clots from building up in a person's arteries. Your arteries are not a place you want blood clots to form, because they can lead to a heart attack or stroke. Scientists have learned how to control this anticoagulant and now package it as a prescription drug, Coumadin, to help save lives.

Vitamin K is not only important for blood clotting; it is also needed for bone health. Your body needs vitamin K so it can use calcium to build strong bones. If you have a vitamin K deficiency, then you are more susceptible to osteoporosis. Osteoporosis is a loss of bone density that increases the risk of fracture.


So, how do you make sure you're getting vitamin K into your body? Well, you could start by eating some kale and a kiwi since both are good sources of vitamin K. But there are other plant-based foods that are natural sources of the vitamin, including spinach, Brussels sprouts and turnip greens. Did you notice that these vegetables are all green? That's because chlorophyll, which is the green pigment in plants that is used in photosynthesis, is also the substance that provides vitamin K. There are a few other sources, but these green ones are great choices.

Now, you might not eat a lot of these foods, but fortunately, your body has a built-in back up plan to help you meet your vitamin K needs thanks to bacteria in your large intestine that make vitamin K. Of course, if something happens to compromise these bacteria, it could lead to an increased risk of deficiency. For example, extended use of antibiotics can kill the bacteria. Newborns are also at risk because the bacteria have not fully developed, and there isn't much vitamin K transferred from the mother. So, newborns are often given vitamin K injections to guard against deficiency.

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