To get the most out of your apples, keep the skin on—it includes half the fiber and numerous polyphenols. Apples are high in fiber and vitamin C. They also contain polyphenols, which have been linked to a variety of health advantages. Apples are a good source of potassium, folate, and magnesium. They also have more calcium than milk. The pulp inside the apple is made up of water, carbohydrates, protein, and fat. The apple's core has some value too - especially if you want to eat more fruits and vegetables. The pectin in the core can be used as a natural thickener for sauces and stews. It can also help control blood sugar levels because it is a form of fiber. The cellulose and lignin found in the core material can aid in digestion by providing food for bacteria that live in the gut. This benefit is one reason why including fruit in your diet instead of relying only on vegetables is so important. Apple skins contain phytochemicals that have anti-cancer properties. These compounds include flavonoids and phenolic acids. Scientists think these chemicals may prevent cancer by preventing tumor growth or spreading by blocking molecules needed for tumors to grow and spread. Apple skins also contain vitamin K, copper, and fluoride. Vitamin K helps control blood clotting and prevents bone loss. Copper is needed for healthy bones and teeth while fluoride helps prevent tooth decay.