"It is a good thing for health to eat vegetables."
Translation:Is rud maith é don tsláinte glasraí a itheadh.
It's the past tense saorbhriathar (bia nár itheadh - "uneaten food"/"not eaten food"), the past habitual and it occurs in some imperative constructions.
The EID even includes this example:
"To spoon up one's porridge" - do chuid leitean a itheadh suas le spúnóg
suggesting that this is either an older spelling, or a valid variant.