Importance of Nutrition to the Digestive System

The human diet should be well balanced to provide nutrients required for bodily function and the minerals and vitamins required for maintaining structure and regulation necessary for good health and reproductive capability (Figure).

Healthy diet logo shows a plate divided into four sections, labeled “fruits”, “vegetables” “grains,” and “protein”. The vegetables section is slightly larger than the other three. A circle to the side of the plate is labeled “dairy”. Beneath the plate is the web address “Choose My Plate dot gov”.
For humans, a balanced diet includes fruits, vegetables, grains, protein, and dairy. (credit: USDA)

There are many organs that work together to digest food and absorb nutrients. The mouth is the point of ingestion and the location where both mechanical and chemical breakdown of food begins. Saliva contains an enzyme called amylase that breaks down carbohydrates. The food bolus travels through the esophagus by peristaltic movements to the stomach. The stomach has an extremely acidic environment. The enzyme pepsin digests protein in the stomach. Further digestion and absorption take place in the small intestine. The large intestine reabsorbs water from the undigested food and stores waste until elimination.

Carbohydrates, proteins, and fats are the primary components of food. Some essential nutrients are required for cellular function but cannot be produced by the animal body. These include vitamins, minerals, some fatty acids, and some amino acids. Food intake in more than necessary amounts is stored as glycogen in the liver and muscle cells and in adipose tissue. Excess adipose storage can lead to obesity and serious health problems.