Vitamin K in the Diet - Foods High in Vitamin K

Vitamin K is required for proper blood clotting and bone formation, both of which are brought about by vitamin K helping in transporting calcium in the body. Doctors usually prescribe vitamin K to treat an overdose of the anticoagulant drug, warfarin, and also as a preventive measure against excessive bleeding in patients on warfarin who need to undergo surgery. The letter ‘K’ stands for ‘koagulering’, the Danish word for ‘clotting’, since it was a Danish scientist, Dr Henrik Dam, who discovered vitamin K.

What are the different types of vitamin K?

The intestines can produce vitamin K, a function that can be enhanced by cultured milk, such as yogurt, being included in the diet.

There are two types of vitamin K that occur naturally: K1, which is also known as phylloquinone, occurs in plants; K2, also known as menaquinone, is synthesized by bacteria in the intestines. And then there is vitamin K3, also known as menadione, a synthetic type of this vitamin, which is produced by pharmaceutical companies.

Vitamin K is categorized as a fat-soluble vitamin, which means that it is absorbed by the body and is deposited in fat tissues, thus reducing the requirement of ingesting it in large quantities. This can lead to two possibilities: Firstly, that taking too much of vitamin K may result in toxicity, and secondly, the symptoms of a deficiency of vitamin K may take years to manifest itself.

What is the recommended dietary allowance of vitamin K?

The recommended dietary allowance, or RDA, for vitamin K is 80 micrograms (mcg) per day for men and 65 mcg for women. While some of this is produced by the microbes in the intestines, most of it is ingested in the food we eat. While, care must be taken to be aware that this recommended dosage is just the minimum that is required each day in order to avoid deficiency in this nutrient, however, neither should it be consumed in excess of the recommended amounts – except under stringent medical supervision – due to the potential of high toxicity levels developing since it is a fat-soluble vitamin.

What are the symptoms of a deficiency in vitamin K?

In adults, a deficiency of vitamin K can manifest itself in internal hemorrhaging and nosebleeds.

In newborn babies, its deficiency causes hemorrhagic disease, hematuria and postoperative bleeding. It can also result in inter-cranial hemorrhages and muscle hematomas.

What are the symptoms of excessive intake and toxicity of vitamin K?

In otherwise healthy people toxicity rarely occurs due to the dietary ingestion of vitamin K, although it can take place if vitamin K3, the synthetic form of the vitamin, is taken. Excessive intake and toxicity of vitamin K can result in sweating and flushing. Anemia and jaundice may also occur.

People who are on medication for the prevention of blood clotting need to consult their doctors before taking a supplement of vitamin K.

What are the various effects of vitamin K in the diet?

As has been mentioned above, vitamin K is utilized by the body for controlling blood clotting. It is essential for the creation of the liver protein, prothrombin, which precedes the formation of thrombin, which in turn is a vitally important factor in the clotting of blood.

Also, since vitamin K is associated with the formation and repair of bone, it is thought to alleviate the severity or incidence of osteoporosis as well as slow loss of bone.

Vitamin K also helps in converting glucose into glycogen in the intestines, which is then stored in the liver.

Why is vitamin K in the diet important for people on warfarin?

There are several medical conditions wherein excessive clotting in the body needs to be prevented. Blood clots in the arteries, veins and heart can cause phlebitis, strokes and heart attacks. Warfarin, a blood thinner, is one of the drugs that is used for preventing clots forming in such patients. Warfarin does this by interfering with prothrombin being produced in the liver. Every patient prescribed warfarin has to undergo a blood test known as prothrombin time, or P.T., or pro time, in order to determine the correct dosage of warfarin. An excessive dosage of warfarin results in bleeding, while a dosage that is too low does not prevent the clotting.

So, the reason why vitamin K in the diet is important for people on warfarin is that if too much of it is consumed, it can interfere with the effects of warfarin, resulting in blood clots forming.

However, people on anticoagulant medications need not avoid foods that contain vitamin K altogether. Rather, they need to keep the consumption more or less consistent, instead of ingesting a lot of it one day and too little the next. This will help in allowing the anti-clotting drug to work, controlling the formation of blood clots. It can be helpful to keep a food diary to monitor the potential interaction between the medication and the diet. In case the P.T. gets too low, the doctor will be able to consult the food diary to determine if too much of foods containing vitamin K has been eaten.

What are the foods high in vitamin K?

Green leafy vegetables are the highest source of vitamin K. Some of these are celery, spinach, Swiss chard, kale, collard greens, watercress, Brussels sprouts, scallion, endive, broccoli, lettuce, turnip greens, cabbage, mustard greens, spring onions, and asparagus. Vitamin K is also found in cheese, liver, bacon, coffee, and green tea.