Zinc and vitamin A together can produce a synergistic effect to improve vision, immunity and other vital functions.

Mark Gurarie is a writer covering health topics, technology, music, books, and culture. He also teaches health science and research writing at George Washington University's School of Medical and ...

DEAR DR. ROACH: If I am taking vitamin A, what is a reasonable dose? I have seen reports that taking too much can cause liver damage, but nobody says how much is a problem. -- M.E.B. ANSWER: I think ...