dary LI is generally caused by a nutritional problem or a sickness that results in a person's inability to digest lactose. At birth, virtually all humans have lactase enzymes, and thus the ability to digest lactose. As people age, some of them lose lactase enzymes. The age when people start to lose lactase and the amount finally retained differ greatly, so people are affected by LI in varying degrees. Some people have virtually no tolerance to dairy products at all, while others are affected only mildly. People with zero tolerance levels normally must completely avoid milk products. Most lactose intolerant people, however, can tolerate differing amounts of lactose in their diets, depending on their lactase deficiency. The three predominant methods of determining if a person is lactose intolerant are known as the lactose challenge test, the blood sugar test and the hydrogen breath test (Englert and Guillory 904). In all three of these tests the patient is given a known quantity of lactose (normally the amount found in one quart of milk), called a lactose load. In the lactose challenge test the effects of the lactose load such as cramping, gas and diarrhea are then carefully monitored. If a person has these LI symptoms, he or she is presumed to be lactose intolerant. In the blood sugar test, blood sugar levels are monitored through blood samples after the consumption of the lactose load. If the sugar level does not rise to a prescribed level, the patient is determined to be lactose intolerant because if the lactose had been digested the blood sugar level would have risen. In the hydrogen breath test the hydrogen level of the breath is monitored after ingestion of the lactose load. Higher than normal hydrogen levels will appear in the breath if the lactose is not digested because undigested lactose is fermented in the colon. Fermentation releases hydrogen which is absorbed into the blood and ultimately exhaled through the lungs. Once a per...
