おぎな
oginau

Godan Verb (u)

1. to supplement; to make up for; to compensate for; to cover (a shortage, loss, etc.); to fill (e.g. a vacancy)

Transitive
あなたの食事 しょくじにはビタミンを おぎなうほうがよい。
anatano shokujiniwa bitamin'o oginau hōga yoi.
You had better supplement your diet with vitamins.