GI System, Nutrition, Appetite

Unit 5

The intake of nutrients, water, vitamins and minerals through food and the processing of food for assimilation into the body are essential for sustaining life. This unit explores the osteopathic physician’s care of patients with syndromes and diseases that result from abnormal nutritional intake, disruptions in the normal structure and function of the gastrointestinal (GI) system, and abnormal food-associated appetites that are related to behavioral, social, economic and environmental factors. This patient care is examined through participation in case-based group learning and community-engagement activities that are integrated applications of pertinent biomedical, epidemiological, bioethical, and public health principles and osteopathic treatment modalities.


Food is required for body growth and sustenance throughout a person’s entire life. This core need for food underlies much human creativity and cultural expression, as seen, for example, in the selection, preparation, presentation and partaking of food in the rituals of daily meals, social gatherings, and religious ceremonies. It can be said that food has a part in shaping the human spirit. “Breaking bread” together is often part of the celebrations of our capacity to enrich our being. And the loss of ability to utilize food well can result in untold suffering. Ingestion of food that contains the body’s needed nutrients in proper forms and required amounts is the core of a healthy diet. A healthy diet contributes significantly to a person’s feeling well, living with healthy energy, and preventing illness. Diet is also an essential part of the treatment plan for many illnesses. A proper diet has the potential to significantly reduce morbidity and mortality throughout one’s life span. While the body’s need for food is the primary motivator for food intake, it is also true that a large number of behavioral, social, economic, and environmental factors influences a person’s appetite for the amount and kind of food intake. The impacts of these additional factors are observed in food-related syndromes that are in a continuum between emaciation of malnutrition and morbid obesity. Patients rely on their physicians to help them evaluate the quality of popular nutrition, diet, and supplement claims and deal with struggles with under- and overeating.

Assimilation of food into the body is accomplished by the gastrointestinal (GI) system. From the moment food enters the mouth, digestive enzyme and hormone secretions, neural reflexes, GI motility and GI blood flow are all cooperatively altered so that ingested food is digested and absorbed. The GI tract also harbors beneficial symbiotic organisms (probiotics) that have important supportive functions. Through its built-in immune system, the GI system also prevents ingested pathogens from damaging the GI system or causing internal harm by entering the body. Thus, a properly working GI system is essential for the well-being of the body.

Acute and chronic disruptions of normal GI system structure and function are very common. The National Institute of Diabetes and Digestive and Kidney Diseases reports that digestive diseases in the United States affects 60-70 million persons and was the reason for 48.3 million ambulatory care visits in 2010.1 Abdominal pain prompted 15.9 million outpatient clinic visits in 2009.2 Diarrhea, constipation, vomiting, or nausea were presented in 13.1 million outpatient clinic visits in that same year.2 Gastroenteritis, gastrointestinal ulcers, liver cirrhosis, gallstones, gastroesophageal reflux disease (GERD), appendicitis, irritable bowel syndrome, and colon cancer are examples of other common GI system disorders. When compromised by disease, organs of the gastrointestinal tract also manifest visceral and neural reflex-related somatic dysfunction, which can be addressed with osteopathic manipulative treatment as part of a comprehensive patient care plan.

This unit addresses the clinical endeavor to relieve the suffering and aid the healing of those who are unable to eat the right kinds of food, those who are unable to normally assimilate food into their bodies or eliminate unwanted substances from their bodies, those who are unable to flourish because of metabolic deficits, those who cannot satisfy their hunger, and those whose appetites are incongruent with the needs of their bodies.



1Digestive Diseases Statistics for the United States,

2Perry, Anne F., et al. Burden of Gastrointestinal Disease in the United States: 2012 Update. Gastroenterology, 143(5): 1179–1187, 2012. Version:  2-8-2017