day (Jones et al., 1991; Suttie et al., 1988). Healthy individuals with phylloquinone intakes approaching 80 μg/day have been investigated and have shown no signs of a deficiency, a finding that suggests this level of intake is probably adequate for the majority of the adult population (Bach et al., 1996; Ferland et al., 1993; Suttie et al., 1988). Reported vitamin K intakes are slightly lower for women than men (Booth et al., 1996b; Appendix Table C-10).

Reported phylloquinone intakes of older adults have generally been higher than those of younger individuals, a finding explained by their higher intakes of vegetables (Booth et al., 1996b). Older subjects have been found to be more resistant to vitamin K deficiency than younger adults (Ferland et al., 1993).

The AI is based on median intake data from NHANES III (Appendix Table C-10). Because dietary intake assessment methods tend to underestimate the actual daily intake of foods, the highest intake value reported for the four adult age groups was used to set the AI for each gender; numbers are rounded up to the nearest 5 μg.

Data pertaining to vitamin K status of pregnant women are limited but suggest that status is not different from that of nonpregnant women, that is, lack of signs of clinical deficiency and comparable circulating vitamin K concentrations (Mandelbrot et al., 1988; von Kries et al., 1992). Furthermore, there are no data on the vitamin K content of fetal tissue for estimating additional needs during pregnancy. Therefore, median vitamin K intake was used for setting the