If by an unknown accident the acid secreting cells of the stomach wall

If by an unknown accident the acid secreting cells of the stomach wall of an individual are damaged, digestion of which one of the following biomolecule will be affected to a greater extent ?

Protein only
Lipid
Carbohydrate only
Protein and Carbohydrate
This question was previously asked in
UPSC NDA-1 – 2018
The correct answer is (A) Protein only. The acid-secreting cells (parietal cells) in the stomach produce hydrochloric acid (HCl). HCl creates a highly acidic environment (pH 1.5-3.5) necessary for two main functions related to protein digestion: (1) It activates pepsinogen, an inactive enzyme precursor, into its active form, pepsin. Pepsin is the primary enzyme for protein digestion in the stomach. (2) The acid helps denature proteins, unfolding their complex structures and making the peptide bonds more accessible to pepsin.
Stomach acid is crucial for activating pepsin, the main enzyme for protein digestion in the stomach, and for denaturing proteins.
Digestion of carbohydrates primarily begins in the mouth (salivary amylase) and continues in the small intestine. Digestion of lipids primarily occurs in the small intestine with the help of bile and pancreatic lipase. While the acidic environment of the stomach might have minor effects on other biomolecules, its most significant role is in initiating protein digestion.