What substance does the liver secrete to aid in fat breakdown?

The liver secretes bile, which is a critical substance that aids in the breakdown of fats during digestion. Bile contains bile salts, which help emulsify fats, allowing them to be broken down into smaller droplets. This process increases the surface area available for enzymes to act upon, making lipid digestion more efficient.

Bile is produced continuously by the liver and stored in the gallbladder, where it is released into the small intestine in response to the presence of fats in the food. This is essential for the proper digestion and absorption of dietary fats and fat-soluble vitamins (A, D, E, and K).

While insulin plays a role in regulating blood sugar levels and enzymes are involved in various biochemical reactions, neither directly aids in the emulsification and breakdown of fats like bile does. Hydrochloric acid, produced in the stomach, is involved in protein digestion and does not have a significant role in fat digestion.