After the fat is dissolved, it is digested by enzymes from the pancreas and the lining of the intestine. Absorption and Transport of Nutrients Digested molecules of food, as well as water and minerals from the diet, are absorbed from the cavity of the upper small intestine. The absorbed materials cross the mucosa into the blood, mainly, and are carried off in the bloodstream to other parts of the body for storage or further chemical change. As noted above, this part of the process varies with different types of nutrients. Some of our most common foods contain mostly carbohydrates.
Examples are bread, potatoes, pastries, candy, rice, spaghetti, fruits, and vegetables.
Many of these foods contain both starch, which can be digested, and fiber, which the body cannot digest. The digestible carbohydrates are broken into simpler molecules by enzymes in the saliva, in juice produced by the pancreas, and in the lining of the small intestine. Glucose is carried through the bloodstream to the liver, where it is stored or used to provide energy for the work of the body. Table sugar is another carbohydrate that must be digested to be useful. An enzyme in the lining of the small intestine digests table sugar into glucose and fructose, each of which can be absorbed from the intestinal cavity into the blood.