Apples are one of the finest gut cleansers one can find. Malic Acid is great stuff. The old saying that goes, "an apple a day keeps the doctor away", has much more truth behind it, than one would initially suspect.
Grated apple is one of natures best cures for any mild stomach upset or mild food poisoning (I mean mild - if you have serious gut pain or have contracted a major dose of gastroenteritus, that has resulted in severe dehydration or blood in your stools, then a doctor is definitely called for).
Malic acid is an important component of the Krebs cycle (also known as the Citric Acid cycle, which is the bodys chemical cycle which converts foods into energy.
Malic acid is know to be a potent bacteria-killer and a potent energy booster.
I find my overall health has improved since I've made a point of eating one large Fuji apple a day.
Bowel regularity is increased with the addition of an apple a day to ones diet, and bowel regularity is an important part of good health.