What is the role of bile in digestion?

• A. Emulsifies fats
• B. Hydrolyses fats
• C. Neutralizes stomach acid
• D. Digests proteins

Answer: (A)

Emulsification of fats is the key role of bile. Bile contains bile salts that act like detergents, surrounding large fat droplets and breaking them into much smaller droplets. This increases the surface area available for pancreatic lipase to act, making fat digestion more efficient. Bile itself isn’t an enzyme, so it doesn’t hydrolyze fats; lipase does that job after the fats have been emulsified. The emulsified droplets also form micelles that help transport fatty acids and other lipids to the intestinal lining for absorption.

Neutralizing stomach acid is not the main function of bile; that acid–base adjustment mainly involves bicarbonate from pancreatic secretions as chyme enters the small intestine. Digestion of proteins is carried out by proteases, not by bile.