Student or Learner
to ensure they remain healthy
to make sure that they keep up healthy conditions
to supplement their diet
to keep their bodies pink
to preserve the pink color of their body
Welcome to the forum, Nazim.
I think I can guess the context, but it would be helpful if you told us what this is all about and why you need to rephrase parts of it.
Bear in mind that we don't do students' homework.