An apple a day keeps the doctor away.

Italian translation / traduzione italiana
Una mela al giorno toglie il medico di torno.

Spanish translation / traducción española
Más vale prevenir que curar.

The proverb referring to the the health effects of the fruit, dates from 19th century Wales.
(Phillips, John Pavin -24 February 1866 -. "A Pembrokeshire Proverb")