Why is zinc deficiency commonly associated with diarrhea?

• A. Zinc increases mucous production
• B. Zinc helps regenerate gut epithelium and brush border enzymes
• C. Zinc decreases intestinal motility
• D. Zinc reduces pancreatic enzymes

Answer: (B)

Zinc is essential for maintaining and repairing the gut lining and for the function of brush-border enzymes at the microvilli. When zinc is deficient, the intestinal mucosa has reduced regenerative capacity, leading to villus atrophy and a weaker barrier. At the same time, brush-border enzymes (like lactase and other disaccharidases) have lower activity, impairing digestion and nutrient absorption. This combination promotes malabsorption and an osmotic load in the lumen, drawing water into the intestine and increasing stool output, which manifests as diarrhea. Zinc also supports barrier integrity and immune defense, so deficiency can worsen mucosal damage and infection risk, further contributing to diarrhea. The other options don’t capture the primary mechanism: zinc isn’t mainly about increasing mucus production, reducing motility, or lowering pancreatic enzyme output.