Assertion: vitamin c's role | /r/HasProperty | unclear
Facets:
value: at this time
type: TEMPORAL
Source sentences:
text: At this time, the role of the different forms of vitamin K on arterial calcification and the risk of coronary heart disease is unclear, but it continues to be an active area of research in the general population and in patients with chronic kidney disease .
text: The exact role of vitamin A in the prevention and treatment of acne is unclear.