The primary function of the villi in the small intestine is to increase the absorption of nutrients from food passing through the small intestine. Intestinal villi are small thread-like objects that line the intestines in order to effectively increase the surface area of the intestinal wall.
Compared to an intestine with no villi, the small intestine with villi has an absorption rate of 30 to 600 times higher. Villi can absorb fluids, amino acids, simple sugars and other substances. The substances that are absorbed are then transported into the blood stream through simple diffusion. From there, the substances are transported around the body and either used or stored.