Final answer:
Lactose intolerance is caused by a deficiency of the enzyme lactase, which is necessary to digest lactose found in milk and dairy products. Symptoms can be managed by dietary adjustments or by using lactase supplements. Genetics determine if an individual can digest lactose into adulthood.
Step-by-step explanation:
Lactose intolerance is caused by a deficiency of lactase, the enzyme responsible for breaking down lactose in milk. This condition is not due to a lack of a vitamin or milk in the diet, nor a deficiency of lactose itself.
Lactose intolerance symptoms include bloating, cramps, nausea, and possibly vomiting after consuming dairy products that contain lactose. The condition can be managed by avoiding lactose-containing foods, using lactase enzyme supplements, or consuming lactose-free milk products. It is a common issue, particularly in Asian populations and can manifest during infancy or later in life. Unlike food allergies, lactose intolerance does not involve the immune system.
Genetics play a role in lactose intolerance, particularly in determining whether an individual will retain lactase production into adulthood. In contrast to certain human populations who can digest lactose lifelong, most mammals naturally develop lactose intolerance as they age.