Lactose is a sugar found in milk and milk products. Our bodies produce an enzyme called lactase, which helps us to digest lactose properly.
In some people, the body stops producing adequate amounts of lactase and they become unable to digest the sugar properly, causing gastric discomforts such as gas, bloating, cramps, diarrhea, and nausea.
For some, ingesting small amounts of foods containing lactose may not cause any problems, or those who are lactose intolerant may find that they can eat yogurt and goat's milk, choosing lactose-free products is their best bet.
Since lactose is found only in milk, only products that contain milk can be lactose-free.