There are many symptoms of lactose intolerance. The most common are abdominal pain and bloating. A person can also experience diarrhea or constipation. The myriad of different symptoms can make it difficult for people with the disease to be properly diagnosed. Therefore it is important for people who think that they have lactose intolerant symptoms to have a lactose intolerance test. The result of this test could determine if the person requires treatment of should engage in a specific regimen to improve their health.

Lactose intolerance results from the inability of a person to process lactose. Lactose is a disaccharide, which means it is a simple sugar that contains two sugar molecules. The two molecules are glucose and galactose. In order for the sugars to be absorbed, the disaccharide needs to be broken into the separate sugar molecules. These smaller molecules can easily pass through the wall of the intestines and into the blood stream. From there, the body can process the sugars and turn them into energy.

If a person is lactose intolerant, they lack the ability to break the lactose into the two smaller sugars of glucose and galactose, therefore the lactose is not absorbed. If this occurs, the sugars continue to pass through the intestinal tract and into the colon. While in the colon, bacteria that exist there start to process the sugars. The bacteria contain the enzyme lactase, which breaks the sugar up. After the sugar is broken, the bacteria can use the galactose and glucose as a source of energy. This leads to a huge amount of bacterial metabolism and gas production. The excess gas causes stomach bloating and can be very uncomfortable. The increase in bacterial metabolism is also responsible for diarrhea and other symptoms as they can overgrow their usual amount in the colon.

All humans have the ability to process lactose when they are young. Lactose is the principle sugar in milk, and babies need to be able to break down breast milk. But as a person gets old, they can lose the lactase enzyme and then they are unable to break down lactose. Certain ethnic groups tend to lose this enzyme quickly while some can retain the enzyme for their entire life time. The lack of the enzyme then results in lactose intolerant symptoms that have have already been described and are very troublesome.

The best way to determine if a person is lactose intolerant is to perform a lactose intolerance test. This involves changing a persons diet to completely eliminate lactose. This lactose intolerance diet does not contain any diary products, so the person has to avoid milk, cheese, ice cream, etc. for a period of time. If their condition improves by the elimination of these foods, then the symptoms can be due to lactose intolerance. While it is difficult to maintain a lactose intolerance diet, it will completely prevent the symptoms of lactose intolerance.