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Elderly persons in good health are not known to have an increased need for vitamin K. On the other hand, 75% of an older hospitalbased population had a hypoprothrombinemia that was responsive to vitamin K treatment (Hazell and Baloch, 1970). Chronic disease, drug therapy, and poor diet may well have contributed to the hypoprothrombinemic condition of this group. Trauma, physical debilitation, renal insufficiency, and chronic treatment with large doses of broad-spectrum antibiotics increase the risk of vitamin K insufficiency (Ansell et al., 1977).

Pregnancy and Lactation 

Data are insufficient to establish an RDA for vitamin K during pregnancy. Because vitamin K consumed in usual diets generally exceeds the RDA established for adult women, additional increments to usual intake are not recommended. Lactation imposes little additional need, since vitamin K consumed in usual diets generally exceeds the RDA. Therefore, additional increments are not recommended.

Infants and Children 

The newborn infant has low plasma prothrombin levels. Although some hypoprothrombinemic infants respond to vitamin K treatment, other factors, including immaturity of the liver, may cause hypoprothrombinemia in the newborn (Suttie, 1984). Because human milk contains low levels of vitamin K (2 µg/ liter) and the intestinal flora are limited, exclusively breastfed infants who do not receive vitamin K prophylaxis at birth are at very real risk of developing fatal intracranial hemorrhage secondary to vitamin K deficiency (Lane et al., 1983). Home-delivered, breastfed infants require particular attention in this regard.

A recommended range of total intake for infants is 5 µg of phylloquinone or menaquinone per day during the first 6 months of infancy and 10 µg during the second 6 months. Newborn infants are routinely given a supplement of vitamin K by intramuscular injection to prevent hemorrhage (AAP, 1985). The usual dose is 0.5-1.0 mg for full-term infants and at least 1 mg for preterm infants. Infant formulas should contain 4 µg of vitamin K per 100 kcal (AAP, 1985). In the absence of specific information about the vitamin K requirements of children, RDA values for them are set at about 1 µg/kg body weight.

Other Considerations

In persons treated with anticoagulant drugs, such as the 4-hydroxy coumarins, vitamin K status should be carefully monitored. Acci-