Concepts and Controversies in Evaluating Vitamin K Status in Population-Based Studies

Shea MK, Booth SL · Nutrients

Explains why the cohort literature is a K1 literature: US food-composition databases are near-complete for phylloquinone and thin for menaquinones, circulating menaquinones are generally undetectable unless large amounts are eaten, and there is no gold-standard biomarker of vitamin K status — the right one depends on which vitamin-K-dependent protein the disease involves.

Population

Methodological review of dietary and biochemical vitamin K status measures used in population studies

Intervention

Phylloquinone intake and circulating measures; undercarboxylated fractions of vitamin-K-dependent proteins

Comparator

n/a

Limitations

A methodological review rather than new data; it frames how to read the observational literature and adds no evidence of its own.