Which enzyme in the mouth initiates carbohydrate digestion?

• A. Salivary amylase
• B. Pepsin
• C. Lipase
• D. Protease

Answer: (A)

Carbohydrate digestion begins in the mouth thanks to salivary amylase, produced by the salivary glands and secreted into saliva. This enzyme starts breaking down starch by cleaving alpha-1,4 glycosidic bonds, producing smaller sugars like maltose and dextrins, giving the first step of digestion as soon as we chew. Its activity works best in the mouth’s neutral to mildly acidic environment, but it’s quickly inactivated once the food reaches the stomach, so most carbohydrate digestion continues in the small intestine with pancreatic amylase and brush border enzymes. The other enzymes listed do not initiate carbohydrate digestion in the mouth: pepsin digests proteins in the stomach; lipase digests fats; protease targets proteins. (Lingual lipase in the mouth handles fats, not carbohydrates.)