Milk is known for building strong bones, but for some, it will weaken the immune system. Between two to five percent of children are allergic to milk during their first year of life. Luckily, most will outgrow this allergy by age three, but some will retain it forever. There is a difference between milk allergies and lactose intolerance. The allergy is an immune response to proteins in milk, whereas being lactose intolerant means your body simply can't properly digest lactose, a sugar found in milk.
