Response of vitamin K status to different intakes and sources of phylloquinone-rich foods: comparison of younger and older adults

Booth SL, O'Brien-Morse ME, Dallal GE, Davidson KW, Gundberg CM · The American Journal of Clinical Nutrition

A controlled feeding study rather than a questionnaire: vitamin K status responds to how much phylloquinone is eaten and to which food it comes from, and the response differs between younger and older adults. The practical consequence is that 'eat more greens' is not a single dose.

Population

Younger and older adults on controlled diets

Intervention

Different intakes and food sources of phylloquinone

Comparator

Within-study comparison across intake levels and sources

Limitations

Metabolic-ward feeding study with biochemical status as the endpoint, small by modern standards, and no joint outcome anywhere in it.