What Is Vitamin K?

Foods Containing Vitamin K
The leafy greens in salad are an important source of vitamin K.

Knowing the answer to the question "What is vitamin K?" is important for optimal nutrition.

What is Vitamin K?: Advantages and Health Benefits

Vitamin K is a fat-soluble vitamin with a name that is derived from the German word "koagulation."

Vitamin K offers several health benefits, including:

  • Helping blood clot normally when you are injured
  • Maintaining bone health and preventing osteoporosis
  • Reducing the risk of cardiovascular disease
  • Preventing the formation of kidney stones
  • Controlling body, fecal, and urinary odor

When answering the question "What is vitamin K?" you must consider that there are two basic types of this important vitamin:

  • Phylloquinone occurs in plants and is the type of vitamin K found in the foods you eat. It is nontoxic and absorbed better when it is consumed with fat.
  • Menaquinone is produced by bacteria in the intestine. However, only small amounts of it can be absorbed in the body. This form of vitamin K is sometimes used for dietary supplements.

The current dietary recommendation for vitamin K is 90 micrograms per day for women and 120 micrograms for men. However, there are some experts who believe this amount should be higher for maximum nutritional benefits. In many European countries, doctors regularly recommend that patients take 200 to 300 micrograms of vitamin K per day.

Foods Rich in Vitamin K

Generally, the best dietary sources of vitamin K are green, leafy vegetables.

Foods with more than 100 micrograms of vitamin K per serving include:

  • Swiss chard
  • Kale
  • Parsley
  • Brussel sprouts
  • Spinach
  • Purslane
  • Broccoli
  • Turnip greens
  • Watercress
  • Endive
  • Spring onions
  • Mustard greens
  • Cabbage
  • Pistachio nuts
  • Coleslaw

Foods with 10-50 micrograms of vitamin K include:

  • Soybeans
  • Red cabbage
  • Avocados
  • Asparagus
  • Soybeans
  • Peas
  • Dill pickles
  • Kiwifruit
  • Sauerkraut
  • Pea pods
  • Abalone
  • Lentils
  • Kidney beans
  • Cucumber
  • Carrots
  • Sweet peppers
  • Pumpkin
  • Leeks
  • Artichokes
  • Celery
  • Plums

Foods with 1-10 micrograms per serving of vitamin K include:

  • Canned tomato sauce
  • Tomatoes
  • Lima beans
  • Blueberries
  • Meatloaf
  • Mackerel
  • Black eyed peas
  • Apricots
  • French Fries
  • Tomato juice
  • Sweet potatoes
  • Potatoes
  • Spaghetti sauce
  • Cheddar cheese
  • Grapes
  • Squash
  • Instant oatmeal
  • Bread
  • Peaches
  • Beets
  • Soy milk
  • Tofu
  • Bran flakes
  • Onions
  • Navy beans
  • Saltine crackers
  • Cranberry sauce
  • White rice
  • Parsnips
  • Sour cream
  • Pretzels
  • Cantaloupe

If you're looking for detailed information regarding the specific nutritional content of a particular food, one excellent resource to bookmark is the USDA National Nutrient Database. This Web site contains complete nutritional data on everything from baby food to prepared snack products.

Symptoms of Vitamin K Deficiency

When asking "What is vitamin K?" be aware that vitamin K deficiency is fairly uncommon in the general population. There is enough vitamin K in the foods we eat that most people have no problem meeting the recommended daily intake. However, people suffering from a vitamin K deficiency often exhibit the following symptoms:

  • Heavy menstrual periods
  • Nosebleeds
  • Easy bruising
  • Gum bleeding
  • Blood in the urine
  • Gastrointestinal bleeding

In pregnant women, a vitamin K deficiency has been linked to the following birth defects:

  • Cupped ears
  • Flattened nasal bridges
  • Shortened fingers
  • Underdevelopment of the nose and mouth

Many multivitamins do contain vitamin K, but there are also supplements that you can purchase if necessary. If you are concerned about your daily intake of vitamin K, discuss the issue of dietary supplements with your doctor.


Although vitamin K provides many health benefits, increasing your vitamin K intake is not always a good idea. People taking anticoagulant or "blood thinner" types of drugs such as Coumadin must be extra cautious with their vitamin K intake. Studies have proven that vitamin K works to counteract the effect of these medications.

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What Is Vitamin K?