It is a fat-soluble vitamin and it is also known as antihaemorrhagic factor.
Dam discovered this vitamin after studying haemorrhagic disease in chickens in 1930 and 1933.
Two naturally occurring vitamins K are vitamin K1 (phyllouinone, phytonadione) and vitamin K2 (flavinoquinone, farnoquinone Activity is apparently related to the presence of methyl group at 2 positions in the quinonoid ring. Synthetic vitamin K is called vitamin K2 (commercially menadione).
It is fat-soluble; heat stable and can stand cooking. Vitamin K1 is yellow viscid oil, but vitamin K2 is a yellow, crystalline solid. The K vitamins are readily destroyed by light, alkali & alcohol.
Sources of vitamin K
Vegetable sources are rich, such as cabbage, spinach, alfalfa, tomato, and soyabin, etc. It is absorbed from the intestine with the help of bile salts. Most putrefied animals and plants contain considerable amount of vitamin K. It has also been produced synthetically. Under normal circumstances, normal intestinal bacteria synthesize adequate amounts. Excessive amount of vitamin A administration in certain species produces interference with bacterial synthesis of vitamin K in the intestine producing prothrombinaemia and haemorrhagic manifestations. Cows milk is a richer source of vitamin K than human milk. Vitamin K is stored in the liver.
Food |
Vitamin K |
Food |
Vitamin K |
Collared green |
440 |
Cabbage |
145 |
Spinach |
380 |
Asparagus |
60 |
Broccoli |
180 |
Okra |
40 |
Brussels sprouts |
177 |
Green beans |
33 |
Olive oil |
55 |
Lentils |
22 |
Functions of vitamin K:
It helps to maintain the formation of normal prothrombin and factor VII in the blood and thus takes part in normal coagulation. It has been postulated that vitamin K acts as the prosthetic group to an apoenzyme to produce a holoenzyme, which is involved in the clotting, reactions. Prothrombin and factor VII are formed in theliver. The principal overall effect of vitamin K is to shorten the prothrombin time. It is also known that vitaminK1 is an essential component of phosphorylation in both the processes of photosynthesis in green plants and animal tissues, as a cofactor necessary in oxidative phosphorylation.
Bile salts are necessary for the absorption of vitamin K. In jaundice and in certain diseases of liver, when the bile secretion is defective, vitamin K fails to be absorbed resulting haemorrhages. Hepatic disease also produces hypoprothrombinaemia, which is corrected by vitamin K administration. The haemorrhagic disease in the newborn is believed to be due to lack of Vitamin K, since vitamin K deficiency in the newborn is due to absence of bacteria in their gut. An important therapeutic use of vitamin K is as an antidote to the anticoagulant drugs such as dicumarol.
Studies have shown that the vitamin K1 and K2 are also preventive against cancer. Vitamin K is one of the most important nutritional requirements for improving bone density. It serves as the biological "glue" that helps to bind the calcium into the bone matrix. Vitamin K helps to prevent hardening of the arteries, which is a common factor in coronary artery disease and heart failure.
The pancreas, which makes insulin, has the second highest amount of vitamin K in the body. Japanese researchers found that vitamin K deficiency can have effects similar to diabetes.
Deficiency signs of vitamin K
Defective blood coagulation and haemorrhages. In vitamin K deficiency, the prothrombin content of blood is decreased and the blood clotting time is considerably prolonged. Deficiency of vitamin K may lead to Alzheimer’s disease.
Who needs vitamin K
If a patient has a history of osteoporosis or coronary heart disease, he may require supplements of vitamin K. Chron’s disease, ulcerative colitis, celiac disease and other conditions that interfere with nutrient absorption also occurs due to Liver disease that interferes with vitamin K storage Taking drugs such as broad-spectrum antibiotics, and aspirin also produces deficiency of vitamin K.
Who does not needs vitamin K
Pregnant and nursing mothers should avoid vitamin K supplements intakes higher than the RDA (65 mcg) unless specifically recommended and monitored by their physician. Those who have experienced stroke, cardiac arrest, and those prone to blood clotting should not take vitamin K without consulting their physician.
Daily requirement:
Normal mixed diet supplies this vitamin in adequate amount. In the treatment of haemorrhagic diseases produced as a result of vitamin K deficiency, 5 mgm is given orally or by injection. It is believed that in adults, the bacteria in the gut synthesize quite a good amount of vitamin K.
Pediatric:
- Infant’s birth to 6 months: 2mcg
- Infants 7 to 12 months: 2.5 mcg
- Children 1 to 3 years: 30mcg
- Children 4 to 8 years: 55 mcg
- Children 9 to 13 years: 60 mcg
- Adolescence 14 to 18 years: 75 mcg
- A single injection of vitamin K is also given at birth.
Adults:
- Males 19 years and older: 120 mcg
- Females 19 years and older: 90 mcg
- Pregnant and breastfeeding females 14 to 18 years : 75 mcg
- Pregnant and breastfeeding females 19 years and older: 90 mcg
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a no-no
in case of BILE DUCT OBSTRUCTION