Apples are not a miracle cure or preventative. Eating healthy, getting exercise and maintaining a proper weight can prevent Type II diabetes or lessen its severity. Apples are fine, but so are other fruits and vegetables.
As for dairy and caffeinated coffee or tea -- well, you might not be able to go hog-wild with those if you have heart disease or conditions that can lead to heart disease, such as high blood pressure or high cholesterol.