Assertion: vitamin e's role | /r/HasProperty | unclear
Facets:
value: at this time
type: TEMPORAL
Source sentences:
text: The exact role of vitamin A in the prevention and treatment of acne is unclear.
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 .