While a true allergy to milk and milk products is rare, there are a large number of people who experience lactose intolerance to a greater or lesser degree.
Lactose is the sugar contained in milk. People who are lactose intolerant lack an enzyme that the body uses to break down lactose into components they can use. This enzyme is called lactase.
Most of us produce plenty of lactase as infants, but around age 2, our production of this enzyme slows. In some people it stops all together.
Lactase supplements can be purchased, and some dairy products are available that come with this enzyme already added.
Here are some of the symptoms of lactose intolerance:
- Halitosis, or bad breath
How severe these symptoms are depends on how intolerant you are of lactose, and how much lactose you consumed.
These symptoms can begin anywhere from 5 minutes to 2 hours after you have consumed a product containing milk. These symptoms can also last as long as three days. Because the onset of symptoms is not always immediate, it can be hard to determine if lactose intolerance is the culprit.
Your best bet is to keep a careful food diary and look for any patterns of discomfort after the ingestion of dairy products. Alternatively, some individuals have eliminated all dairy from their diet for a period of a few days and then gradually added dairy back to determine the culprit.
Some individuals with lactose intolerance are able to consume yogurt with active cultures as well as cheese, since these products contain less lactose.