Occurrence and Requirements

Phylloquinone (vitamin Kj) is present in variable concentrations in the chloro-plasts of green plants, where it is needed for photosynthesis. Gram-positive bacteria, like certain strains of Escherichia coli and Bacteroides fragilis produce menaquinones (vitamin K2), which animals obtain from plant foods, together with K-|. So vitamin K can be obtained from both plant and animal foods (A). Green vegetables like green cabbages, green lettuces, broccoli, and chives are excellent sources of vitamin K. This is why older textbooks still suggest that patients on coumarin drugs avoid eating cabbage. When using anticoagulants as thrombosis prophylaxis, a balance between the agonist vitamin K and the coumarin antagonist has to be maintained. With larger amounts of vitamin K, the balance shifts in favor of the agonist, resulting in an increased tendency towards coagulation. However, more recent research shows that such a shift is unlikely to occur due to nutritional vitamin K. Hence, the more recent recommendation is that patients receiving coumarin drugs do not have to pay attention to the vitamin K content of their foods, as long as they maintain their usual diet. If a major change is made, such as a change from a mixed to a strict vegetarian nutrition, pro-thrombin time must be checked. Estimates of Adequate Intakes (B) for vitamin K are imprecise since they are based on the uncertain synthesis by intestinal bacteria. For adults, estimates are 65-80 ug/d; requirements are slightly higher during pregnancy and lactation. Actual vitamin K intakes are unknown since, in the past, sufficiently reliable analytical techniques to determine K contents of foods were not avail able. It can be assumed, however, that more than sufficient amounts are supplied with a mixed nutrition. There is no known toxicity from vitamin K from foods. No UL has been established.

Classic vitamin K deficiencies (C) are usually found only in infants who are exclusively breast-fed. It causes bleeding, the most feared variant of which is bleeding into the ventricles of the brain. This can cause irreversible damage including death; prophylaxis is, therefore justified, even if without it, there would only be a few cases per year. One mg intramuscular (IM) vitamin K or 2 mg orally on the 1st and 5th day of the neonate's life, repeated during the 4th-6th week, can prevent most cases of bleeding caused by vitamin K deficiency.

Until 1991, IM administration of vitamin K was practiced almost exclusively. Then, a scandal hit the press: Scandinavian research showed a correlation between IM prophylaxis and the frequency of brain tumors. Other studies were unable to confirm this; further, influences of other factors like solvents or other additives to the IM solution cannot be excluded. No such correlations have been found for oral vitamin K prophylaxis.

- A. Occurrence and Daily Requirement -

The daily requirement of 65 p,g vitamin K is contained in:

1.51 whole milk

220g cream cheese (20% fat)

100 g butter

3 eggs

400g pork

300g pork liver 150 g beef liver 50g calf liver

1.51 whole milk

220g cream cheese (20% fat)

100 g butter

3 eggs

400g pork

300g pork liver 150 g beef liver 50g calf liver

Vitamin Cream

75g rosehips

500 g strawberries

75g rosehips

500 g strawberries

400g turnips 15g chives

130 g asparagus (white) 25g Brussels sprouts 60g broccoli 120g potatoes 20g wheat germ 150g whole-grain

B. Adequate Intakes (AI, 2002)

Life Stage and

Age

Vitamin K

Gender Group

(ra/d)

Infants

0 - 6 mo

2.0

7 - 12 mo

2.5

Children

1- 3 y

30

4 - 8 y

55

Adolescents

9 - 13 y

60

14 - 18 y

75

Males

> 19 y

120

Females

> 19 y

90

Pregnancy and Lactation

14 - 18 y

75

19 - 50 y

90

  • C. Typical Extensive Hemorrhages Caused by Vitamin K Deficiency
  • C. Typical Extensive Hemorrhages Caused by Vitamin K Deficiency
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