Apple is a healthy fruit for patients with heart disease because it contains no saturated fat, cholesterol and sodium. Studies have shown that it can protect the health of human cardiovascular system because it contains cellulose with high solubility. About 25% of apple fiber exists in the form of colloid. By reducing the absorption of fat, the blood cholesterol is kept at a normal level. All-functional apple chewing gum can keep blood sugar stable, so apples are not only healthy snacks for diabetics, but also essential fruits for anyone who wants to control blood sugar levels. Canadian research shows that apple juice has a powerful effect on killing infectious viruses in test tubes. People who eat more apples are much less likely to catch a cold than those who don't eat or eat less apples. Therefore, some scientists and doctors call apples "all-round healthy fruits" or "general practitioners". Treating diarrhea in the folk, apples have been used to treat diarrhea and constipation for a long time, which shows its rare two-way regulation. Applesauce and apples with skins are good medicines for diarrhea, and drinking a glass of apple juice and water on an empty stomach in the morning is the best choice for relaxing bowels. Generally speaking, eating 25 to 35 grams of dietary fiber every day is essential for constipation. For some children with chronic diarrhea, drinking too much apple juice will aggravate diarrhea because they can't fully absorb carbohydrates (sugar) in apples. Eating 2 ~ 3 apples a day is enough to achieve the above effect, but the juice squeezed from 2 ~ 3 apples can't achieve the effect of the whole apple. The research team at the University of California, Davis analyzed the pulp and peel of apples, and found that both of them have antioxidant effects, but the peel contains more flavonoids. Therefore, it is most beneficial to eat apples without peeling and pesticide pollution.