Food digestion occurs in the digestive system, a multi-part collection of organs that includes your digestive tract, as well as several organs that provide substances for the breakdown of food. Your level of digestion is determined by the combined actions of all these constituent parts, as well as by the presence of any diseases or defects that alter your digestive abilities.
Understanding Digestion
Digestion begins when you first place food in your mouth, according to the National Digestive Diseases Information Clearinghouse, also known as the NDDIC. As you chew, enzymes in your mouth start to break down the starch content of your food into its constituent molecules. After you swallow, digestive glands in the lining of your stomach produce stomach acid to break food down further. These glands also produce an enzyme that allows your body to break down food protein. After food passes from your stomach, it enters your small intestine, where digestive juices from your liver and pancreas combine with your food and help break down fats, proteins and carbohydrates. Eventually, your body absorbs food nutrients, minerals and water through the wall of your small intestine.
Hormones and Nerves
The functions of your digestive system are controlled by several hormones that circulate through your digestive tract, the NDDIC reports. Production of stomach acid falls under the control of the hormone gastrin, while the hormone secretin controls digestive juices in your pancreas and encourages your stomach to produce digestive enzymes. In addition, the hormone cholecystokinin, also called CCK, produces pancreatic enzymes and signals your gallbladder to release digestive juices created in your liver. Certain nerves both inside and outside your digestive tract contribute to digestion by controlling the actions of related muscles and influencing the production of digestive juices.
Esophagus Problems
Problems in different parts of your digestive system can hinder your ability to digest food properly, according to the Nemours Foundation. For instance, structural defects in a newborn's esophagus can prevent food from passing properly from the mouth to the stomach. Children and adults can also develop gastroesophageal reflux disease, also called GERD, which typically develops when the muscular sphincter that separates your esophagus and stomach does not work properly and allows partially digested contents to pass back through to your esophagus.
Stomach and Intestine Problems
Problems in your stomach or intestines can also hinder proper food digestion, the Nemours Foundation reports. Common complaints include mild indigestion or diarrhea, as well as pain or cramps resulting from causes such as bacterial, viral and parasitic gastrointestinal infections. Additional potential gastrointestinal problems include chronic inflammation related to inflammatory bowel disease, peptic ulcers and gastritis, irritable bowel syndrome and the gluten sensitivity disorder called celiac disease.
Additional Problems
Digestive problems may also result from disorders of the organs that produce or store digestive juices, including the liver, gallbladder and pancreas, the Nemours Foundation notes. If you have the inherited disease cystic fibrosis, excessive mucus production can block channels inside your pancreas that normally supply digestive fluids. The presence of gallstones or gallbladder inflammation can block the normal transport of digestive juices from that organ. Hepatitis in your liver may block normal digestive fluid production.
