Lactose is found in nature only in milk. It apparently increases the
absorption of calcium. It is a source of galactose, which is necessary for
making galactolipids, which are important fats of the brain. Although there
is a mechanism for making galactose from scratch in the body without eating
it, this may be a further stress on the organism, already getting abnormal
food. There is a rough relationship between the size of an animal specie's
brain and the quantity of lactose in its milk.
Jack Newman, MD, FRCPC