What Causes Lactose Intolerance?

Lactose intolerance is a condition in which the body has difficulty digesting lactose, a sugar found in milk and dairy products. This occurs due to a deficiency of an enzyme called lactase, which is needed to break down lactose into simpler sugars (glucose and galactose) that can be absorbed into the bloodstream. When lactase is insufficient or absent, undigested lactose passes into the colon, where it can cause various digestive symptoms.

The primary cause of lactose intolerance is a genetic and developmental factor:

  1. Primary Lactose Intolerance: This is the most common type of lactose intolerance and develops as a person ages. In many cases, the body naturally decreases lactase production after childhood. Certain ethnic groups are more prone to developing primary lactose intolerance, particularly people of African, Asian, Hispanic, and Native American descent.

However, there are other, less common, causes of lactose intolerance:

  1. Secondary Lactose Intolerance: This type of lactose intolerance is typically temporary and results from damage to the small intestine, which can affect lactase production. Conditions that can cause secondary lactose intolerance include:
    • Gastroenteritis: Infections or inflammation of the gut lining, often caused by viruses or bacteria, can lead to temporary lactose intolerance.
    • Celiac Disease: An autoimmune disorder where the consumption of gluten leads to damage to the small intestine, potentially affecting lactase production.
    • Inflammatory Bowel Diseases: Conditions like Crohn’s disease or ulcerative colitis can damage the intestine and cause secondary lactose intolerance.
    • Radiation Therapy or Surgery: Treatments involving the abdomen or intestine can lead to temporary damage to the intestinal lining and result in lactose intolerance.
  2. Congenital Lactase Deficiency: In rare cases, individuals are born with a genetic mutation that prevents the production of lactase from birth. This condition is known as congenital lactase deficiency and is typically diagnosed shortly after birth.

The symptoms of lactose intolerance can include bloating, gas, diarrhea, and stomach cramps, which occur after consuming dairy products or foods containing lactose. It’s important to note that lactose intolerance is different from a milk allergy, which is an immune response to proteins in milk and can cause more severe symptoms like hives, wheezing, or anaphylaxis.

If you suspect you have lactose intolerance, it’s recommended to consult a healthcare professional for proper diagnosis and guidance on managing your symptoms. Dietary adjustments, such as reducing lactose consumption or taking lactase supplements, are common approaches to managing lactose intolerance.