Which molecule acts as an emulsifier in fat digestion?

Which molecule acts as an emulsifier in fat digestion?

• A. Amylase
• B. Secretin
• C. Bile acids
• D. Protease

Answer: (C)

Emulsification of fats in the small intestine is accomplished by bile acids, which are amphipathic molecules produced by the liver and stored in the gallbladder. Their hydrophobic regions interact with lipid droplets while their hydrophilic portions face the watery lumen, breaking large fat globules into smaller droplets and increasing surface area for pancreatic lipase. This emulsification is essential for fat digestion and leads to the formation of mixed micelles that solubilize fatty acids and monoglycerides for absorption by enterocytes. Amylase digests carbohydrates, secretin is a hormone that stimulates bicarbonate and enzyme secretion, and proteases digest proteins, so none of those act as emulsifiers of fat.

Emulsification of fats in the small intestine is accomplished by bile acids, which are amphipathic molecules produced by the liver and stored in the gallbladder. Their hydrophobic regions interact with lipid droplets while their hydrophilic portions face the watery lumen, breaking large fat globules into smaller droplets and increasing surface area for pancreatic lipase. This emulsification is essential for fat digestion and leads to the formation of mixed micelles that solubilize fatty acids and monoglycerides for absorption by enterocytes. Amylase digests carbohydrates, secretin is a hormone that stimulates bicarbonate and enzyme secretion, and proteases digest proteins, so none of those act as emulsifiers of fat.