Lactase

Definition

Lactase is an enzyme that breaks down lactose, the sugar found in milk and dairy products, into glucose and galactose for easier digestion. This enzyme is crucial for individuals, particularly infants, who consume milk as a primary source of nutrition. Without sufficient lactase, lactose remains undigested in the gut, leading to discomfort and digestive issues.

5 Must Know Facts For Your Next Test

1. Lactase is produced in the small intestine, particularly during infancy when milk consumption is highest.
2. The activity of lactase typically declines after weaning in many mammals, leading to lactose intolerance in adults.
3. Lactase can be supplemented through over-the-counter products for those with lactose intolerance to help digest dairy foods.
4. Some populations, particularly those with a history of dairy farming, have developed genetic adaptations for continued lactase production into adulthood.
5. When lactose is not properly digested, it can ferment in the gut, causing symptoms such as bloating, gas, and diarrhea.

Review Questions

• How does lactase function in the digestion of lactose and what are its end products?
  • Lactase functions by hydrolyzing lactose into its two monosaccharide components: glucose and galactose. This process makes the sugars easier to absorb through the intestinal wall into the bloodstream. When lactase is absent or insufficient, lactose remains undigested, causing digestive discomfort and symptoms associated with lactose intolerance.
• What role does lactase play in managing lactose intolerance and what options are available for individuals affected by this condition?
  • Lactase plays a vital role in managing lactose intolerance by breaking down lactose into glucose and galactose, allowing individuals to digest dairy products comfortably. For those who are lactose intolerant, options include taking lactase supplements before consuming dairy or choosing lactose-free products that have been pre-treated with lactase. These strategies help reduce or eliminate symptoms associated with the consumption of lactose-containing foods.
• Evaluate the evolutionary significance of lactase persistence in certain human populations and its implications for dietary practices.
  • Lactase persistence is an evolutionary adaptation seen in certain human populations that continued to consume dairy into adulthood. This adaptation likely arose due to the advantages of having access to a nutrient-rich food source during periods of scarce resources. The ability to digest lactose allowed these populations to thrive on diets including milk and dairy products, leading to changes in dietary practices and agricultural development. This phenomenon illustrates a clear example of how human genetics can influence dietary habits and cultural practices over time.

Related terms

Lactose: A disaccharide sugar composed of glucose and galactose, found primarily in milk and dairy products.

Lactose Intolerance: A condition characterized by the inability to properly digest lactose due to insufficient lactase production, often leading to gastrointestinal symptoms.

Galactose:

A monosaccharide that, along with glucose, is produced when lactase breaks down lactose.