According to pasta manufacturer Mrs. Weiss, macaroni and noodles are the two basic types of pasta. The primary difference between the two is their ingredients.
Noodles are made with water, egg solids and a type of finely ground semolina flour called durum. Macaroni is made from only normal semolina and water. The inclusion of egg solids is what differentiates noodles from macaroni. There is a mistaken belief that noodles, because of the egg addition, are less healthy. While this is not true, some noodles are made with only egg whites and are therefore cholesterol free, making them a healthier choice than others.