Skim milk is made from regular milk that has had all the cream removed from it. Milk is the only ingredient necessary to create skim milk, but some dairy brands add additional vitamins or ingredients to increase the nutritional value or help with the marketing of their products.
Skim milk is milk that has been processed to contain less than 0.5% milkfat. Removing the fat content of the milk results in the loss of fat-soluble vitamins. In some skim milk brands, additional ingredients are added to replace the nutrients that were removed, and the product is often fortified with milk solids. Vitamin A and vitamin D are also sometimes added to skim milk. Skim milk may also contain additional ingredients for added nutritional value or to help digestion.
Skim milk may also come in a low sodium variety where sodium is replaced with potassium. Flavored skim milk may also contain additional ingredients. Chocolate milk or buttermilk may come in what is labeled as a skim variety, and it is important to check the nutritional information to determine what may have been added to a particular variety.
Milk marketed as lactose free contains additional enzymes to help aid digestion after consumption.