When your small intestine is unable to produce enough of the enzyme lactase, then your body becomes unable to digest lactose, the sugar found in milk and other dairy products. This condition is known as lactose intolerance. Since lactose cannot be broken down, it moves into the colon instead of being absorbed into the bloodstream like it should be. This is what causes the uncomfortable symptoms associated with the condition.
Risk factors for Lactose Intolerance
There are some factors that can increase you or your child’s risk for developing lactose intolerance. These include:
- Age: Lactose intolerance is uncommon in babies and young children. Symptoms usually develop during adulthood and become increasingly likely as you get older.
- Ethnicity: Certain ethnicities are at a naturally higher risk for developing lactose intolerance. These include people of African, Hispanic, Asian, and American Indian descent.
- Premature Birth: Babies who are born prematurely might have temporarily reduced levels of lactase in their systems.
- Small Intestine Conditions: Problems in the small intestine can lead to decreased lactase production and therefore lactose intolerance.
- Some Cancer Treatments: You are at an increased risk for lactose intolerance if you have received radiation therapy for cancer in your abdomen or if you have intestinal complications caused by chemotherapy.
Primary Lactose Intolerance Causes
The most common type of lactose intolerance, primary lactose intolerance, is characterized by normal lactase levels at birth and as a child, but then a sudden depletion of lactase production by adulthood. Most infants will begin life with very high levels of lactase, since a majority of their nutrition comes from milk. Then, as they grow older and begin to introduce other foods into their diet, their lactase levels will naturally decrease but will still be high enough to digest normal amounts of dairy. However, with primary lactose intolerance, lactase levels will continue to drop into adulthood, making it difficult to digest any milk products as you get older.
This form of the condition is genetically determined, meaning that it is inherited. Primary lactose intolerance is more common in people with African, Asian, or Hispanic ancestry. It is also common for people of Mediterranean or Southern European descent.
Secondary Lactose Intolerance Causes
Sometimes an illness, injury, or abdominal surgery can cause your small intestine to decrease lactase production. Some common illnesses that are associated with secondary lactose intolerance include celiac disease, Crohn’s disease, and bacterial overgrowth. When the underlying condition is treated, lactase levels can be restored, which will improve the symptoms of lactose intolerance.
Congenital Lactose Intolerance Causes
In very rare cases, babies can be born with lactose intolerance. This means that they have absolutely no lactase activity at all. This condition is autosomal recessive, which means that the only way that this type of lactose intolerance occurs is if both parents pass on the gene variant to their child.
Also, infants who are born prematurely might have temporary lactose intolerance, since the development of lactase typically occurs late in the third trimester of pregnancy. However, babies who are affected by this will usually grow out of it within a few months, once they grow enough for their bodies to begin producing lactase on their own.
