I think it's important to include vegetables in our diet. They contain antioxidants, vitamins, and minerals a non-veg diet can't provide. Your sentence was correct however it's now prevalent for us to put a comma before "and" and good style to remove the word "that" when not required.

I think it's important to include vegetables in our diet. They contain antioxidants, vitamins, and minerals that a non-veg diet can't provide. Piero: After reading the question I realize it's a question of either a vegetarian diet or not.

I think it's important to include vegetables in our diet. They contain antioxidants, vitamins and minerals that a non-veg diet can't provide.