Lactose Intolerance occurs due to deficiency of \ \ \ \ \ \ \ . - RRB Nsg Superintendent -29 April 2025 (Shift-1st)

RRB Nsg Superintendent -29 April 2025 (Shift-1st)

Biochemistry & Nutrition

Easy

Appeared in: RRB Nsg Superintendent -29 April 2025 (Shift-1st)

Explanation

Lactose intolerance is a metabolic disorder caused by the deficiency of the enzyme lactase.
Lactase is a brush border enzyme in the small intestine responsible for hydrolyzing lactose (milk sugar) into absorbable monosaccharides: glucose and galactose.
In lactase deficiency, unhydrolyzed lactose travels to the colon, where bacterial fermentation causes symptoms like abdominal pain, bloating, flatus, and diarrhea.
This condition can be primary (genetically determined decline in the enzyme) or secondary to intestinal mucosal injury (e.g., from gastroenteritis or celiac disease).

Option A: β-glycosidase is a very broad class of enzymes that cleave glycosidic bonds. While lactase is technically a type of β-galactosidase (a related class), 'Lactase' is the specific and clinically precise name for the enzyme deficient in this condition.
Option B: Amylase is responsible for the digestion of starch (a complex carbohydrate) into smaller sugars. It has no role in the digestion of lactose.
Option C: Isomaltase is part of the sucrase-isomaltase enzyme complex. It digests isomaltose, which is formed during the breakdown of starch. It does not digest lactose.

Visual 1: Diagram: Illustrating the enzymatic action of lactase breaking down lactose into glucose and galactose in the intestinal villi.
Visual 2: Flowchart: Depicting the pathophysiology of lactose intolerance, starting from lactase deficiency, leading to undigested lactose in the colon, bacterial fermentation, and resulting clinical symptoms.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Carbohydrate digestion and enzyme deficiencies as background academic context rather than a clinical decision trigger.
Nurses are central to patient education for managing lactose intolerance. This includes teaching dietary modifications, such as avoiding high-lactose foods, choosing lactose-free alternatives, and reading food labels for hidden lactose.
Since dairy products are a primary source of calcium, nurses should assess the patient's risk for calcium and vitamin D deficiency and recommend alternative sources (e.g., fortified foods, leafy greens) or supplements.
What if? If an infant presents with severe diarrhea and failure to thrive from birth after consuming milk, the nurse should suspect congenital lactase deficiency, a rare but serious condition. The immediate intervention would be to switch to a specialized lactose-free formula.

How to Approach the Question

This is a factual recall question that tests your knowledge of digestive physiology.
Identify the core concept: The question asks for the specific enzyme deficiency linked to 'Lactose Intolerance'.
Analyze the term 'Lactose'. Many enzymes are named by adding the suffix '-ase' to their substrate. Therefore, the enzyme that digests lactose is 'lactase'.
Evaluate the options based on this knowledge. 'Lactase' directly corresponds to the substrate 'lactose'.
Briefly recall the functions of the other enzymes to confirm they are incorrect. Amylase digests starch, and isomaltase digests isomaltose. β-glycosidase is too general.
Select 'Lactase' as the most specific and accurate answer.

Concept Tested & Keywords

QunUvG67-2Gy-SM3grRzi8