What substance is produced by the liver that is critical for digestion?

The liver produces bile salts, which are essential for the digestion and absorption of dietary fats. Bile salts are stored in the gallbladder and released into the small intestine during digestion. Their role is to emulsify fats, breaking them down into smaller droplets that enzymes can more easily act upon. This process significantly increases the surface area available for lipase enzymes to digest fats, making them more accessible for absorption in the intestinal lining.

Bile salts also help with the absorption of fat-soluble vitamins (A, D, E, and K) and contribute to the excretion of waste products, such as bilirubin. The production of bile and its composition is crucial for efficient digestion and plays a vital role in the overall digestive system. Other options represent substances produced in different organs or have distinct functions unrelated to emulsifying fats for digestion.