what is the function of the small intestine

The small intestine’s main job is to finish digesting food and absorb almost all the nutrients and much of the water your body needs.

Quick Scoop

• It completes chemical digestion of carbohydrates, proteins, and fats using enzymes and bile.

• It absorbs about 90% of nutrients (sugars, amino acids, fatty acids, vitamins, minerals, and electrolytes) into the blood and lymph through its villi and microvilli.

• It also absorbs a large amount of water, helping form liquid contents before they move to the large intestine.

• It turns what’s left into waste that passes on to the large intestine.

• It has immune and hormone roles, acting as a barrier to harmful bacteria and releasing hormones that control digestion and appetite.

So in one line: the function of the small intestine is to digest food into small molecules, absorb them into the body, and pass the remaining waste onward.