Apples help regulate your blood sugar. Apples are loaded with phytonutrients including polyphenols,
which help prevent spikes in blood sugar several ways.
Recent research has discovered that the polyphenols in apples can stimulate the beta cells of the pancreas to secrete insulin, helping diabetics and pre-diabetics.
The polyphenols also lessen absorption of glucose from the digestive tract, and stimulate the insulin receptors, increasing the uptake of glucose from the blood.
Also, the flavonoids like quercetin that apples contain inhibit enzymes (including alpha-amylase and alpha-glucosidase) which help break down complex carbohydrates into simple sugars. When these enzymes are inhibited, your blood will have fewer simple sugars.
Apples are among the alkalizing fruits. Unfortunately, apples are often covered in pesticides. If you cannot get organic apples, you may have to cut off the skin, sacrificing some of the nutrients (and cutting off the skin will not eliminate the pesticides that have been absorbed into the flesh of the apple, so the only real solution is to buy or grow your own organic apples).