Superfood from the east significantly reduced cardiac arrests (4)
I believe the answer is:
acai
'superfood' is the definition.
I don't know anything about this answer so I cannot tell whether it can be defined by this definition.
'from the east significantly reduced cardiac arrests' is the wordplay.
'from the east' is a reversal indicator (on a map from right to left).
'significantly' becomes 'ia' (I am not sure about this - if you are sure you should believe this answer much more).
'reduced' says to take the initial letters (the word is reduced to its first letter).
The initial letters of 'cardiac arrests' is 'ca'.
'ia'+'ca'='iaca'
'iaca' back-to-front is 'ACAI'.
Can you help me to learn more?
(Other definitions for acai that I've seen before include "fruit which is nutritious" , "South American food product" , "something nutritional to eat" , "South American palm tree" .)