GI System and Malnutrition Review

Overview of the GI System:

  • Composed of several structures: mouth, pharynx, esophagus, stomach, small intestine, and large intestine

  • Overview of the GI System:

    • The gastrointestinal (GI) system is composed of several structures that play crucial roles in the digestion and absorption of nutrients. These structures include the mouth, pharynx, esophagus, stomach, small intestine, and large intestine. Each part of the GI tract has specialized functions that contribute to the overall digestive process.

    • Accessory digestive organs, such as the liver, gallbladder, and pancreas, support the GI system by producing essential enzymes and substances necessary for digestion.

    • Nutrition is the process in which the body ingests, absorbs, transports, and eliminates nutrients and food.

  • The GI tract is responsible for:

    • Ingestion: The intake of food and liquids, which begins the digestion process.

    • Absorption: The process by which nutrients from food are taken up into the bloodstream for use by the body.

    • Transportation: The movement of food and waste through the digestive tract.

    • Elimination: The removal of undigested food and waste products from the body.

    • The GI tract has its own nervous system known as the enteric nervous system, which controls motility (the movement of food) and secretion (the release of digestive juices) along the entire GI tract.

    • Parasympathetic stimulation increases peristalsis, the coordinated contraction of muscles that moves food through the GI tract, resulting in the gurgling sound commonly noted during GI assessments. In contrast, sympathetic stimulation tends to decrease peristalsis, thereby slowing digestion.

    • It also transports and metabolizes it transports and metabolizes nutrients that are necessary for the life of a cell.

    • The GI tract extends from the mouth, to the anus.

    • Nutrients are broken down into absorbable products by enzymes from various digestive organs.

  • GI Tract Functions:

    •  It breaks down food for digestion

    • The GI tract breaks down food into absorbable products through enzymatic action, allowing nutrients to be effectively utilized by the body.

    • It absorbs these nutrients into the bloodstream while simultaneously eliminating food material and other waste products from the body, ensuring homeostasis and health.

Specific Structures and Functions

  • Mouth: Buccal Cavity:

    • The mouth is responsible for the mastication (chewing) of food and the formation of a bolus, which is a soft mass of chewed food ready to be swallowed.

    • Saliva produced by salivary glands moistens food, facilitating easier swallowing and providing enzymes (such as amylase) that begin the digestion of carbohydrates.

  • Esophagus:

    • The oropharynx (part of the throat behind the mouth) and the laryngopharynx (lower part of the throat above the esophagus) are what move food via peristalsis (wave-like muscle contractions) to the esophagus.

    • The esophagus is a muscular tube that transports food from the mouth to the stomach. It allows the movement of food to the stomach through a series of coordinated muscle contractions known as peristalsis.

    • The epiglottis, a flap of tissue, prevents food from entering the trachea during swallowing. The gastroesophageal sphincter regulates the passage of food into the stomach and prevents backflow.

  • Stomach Regions:

    • The stomach comprises four main areas: the cardiac region (nearest the esophagus), fundus (the upper curved part), body (the central region), and pylorus (the lower part leading to the small intestine).

    • The stomach acts as a storage reservoir where food is held before entering the small intestine. It continues the mechanical breakdown of food through churning action and begins protein digestion through the action of gastric juices, including hydrochloric acid and pepsin (enzyme that breaks down proteins), which help form a semi-liquid mass called chyme.

Parts of Digestive System Overview

Upper Part

  • Mouth

  • Esophagus

  • Stomach

Middle Portion

  • Duodenum

  • Jejunum

  • Ileum

  • Motility and depletion happen here (Motility refers to the movement of food through the intestines, and depletion refers to the absorption of nutrients, reducing the contents in the digestive tract.)

Lower Segment

  • Cecum

  • Colon

  • Rectum

  • Serves as a storage for the elimination of waste (Stores waste material until the body is ready to expel it)

  • Large intestine forms feces and serves as a reservoir for fecal mass until defecation happens (Holds stool temporarily until it is eliminated through a bowel movement.)

Accessory Organs

  • Help dismantle food (Liver, pancreas, gallbladder, and salivary glands produce enzymes and bile to break food into absorbable nutrients.)

  • Regulate the use and storage of nutrients (Control how the body processes and stores nutrients like carbohydrates, proteins, and fats.)

  • Nause & Vomitting
    The Client with Nausea & Vomiting

    • Clinical manifestation

    • Dx Test

    • Drug Therapy

    Chapter 2: Related Malnutrition

  • Malnutrition

  • Definition of Malnutrition:

    • Malnutrition is a condition characterized by a deficit, excess, or imbalance in the nutrient intake of energy or nutrients. It can occur with or without inflammation and can affect overall health and well-being.

    • Malnutrition affects body composition and functional status. Other terms we use to describe malnutrition are undernutrition and overnutrition.

  • Prevalence of Malnutrition:

    • The rates of malnutrition vary significantly across different settings: approximately 30-50% of hospitalized patients may experience malnutrition, whereas around 6% of individuals in community settings and about 50% of those in rehabilitation settings are affected by malnutrition.

  • Types of Malnutrition:

    • Starvation-related: This type of malnutrition is marked by chronic starvation with no inflammation, typically seen in conditions such as anorexia nervosa.

    • Chronic disease-related: This occurs when dietary intake is insufficient due to chronic illnesses that may present with mild to moderate inflammation, seen in conditions associated with Secondary Protein-Calorie Malnutrition (PCM) such as organ failure, cancer, rheumatoid arthritis, and obesity.

    • Acute disease-related or injury-related malnutrition: is related to acute disease or injury states with marked inflammatory response (e.g., major infection, burns, trauma, surgery)

  • Conditions That Increase the Risk for Malnutrition 

    • Chronic alcohol use

    • Drugs with antinutrient or catabolic properties (e.g., corticosteroids, antibiotics)

    • Excessive dieting to lose weight

    • No oral intake (NPO)and/or receiving standard IV solutions for 10 days (adults) or 5 days (older adults)

    • Nutrient losses from malabsorption, dialysis, diarrhea, or wounds

    • Swallowing problems (e.g., head and neck cancer, stroke)

Chapter 3: Contributing Factors to Malnutrition

Contributing Factors of Malnutrition

  • Socioeconomic factors- Food insecurity is a major public health problem. 

  • To help obtain food, people may use “safety net programs.” These include food assistance programs, housing and energy subsidies, and in-kind contributions from relatives, friends, food pantries, or charitable organizations.

  • Physical illnesses- Malnutrition is a common consequence of illness, surgery, injury, or hospitalization. The hospitalized patient, especially the older adult, is at risk for becoming malnourished. Prolonged illness, major surgery, sepsis, draining wounds, burns, hemorrhage, fractures, and immobilization can contribute to malnutrition. Undernutrition can worsen a pathologic condition. An existing deficiency state is likely to become more severe during illness. Anorexia, nausea, vomiting, diarrhea, abdominal distention, and abdominal cramping may accompany gastrointestinal (GI) disease.

  • Incomplete diets- Vitamin deficiencies are rare in most developed countries. When vitamin imbalances do occur, they usually involve several vitamins rather than a single one. This may happen with a person with a pattern of alcohol and drug use, those who are chronically ill, and those who follow poor diet practices.Persons who had surgery on the GI tract may be at risk for vitamin deficiencies.

  • Drug-nutrient interactions- when a drug affects the use of nutrients in the body. Many drugs have side effects, such as changes in taste, appetite and nausea. Grapefruit juice can increase the absorption of some drugs, enhancing their effect.

Chapter 5: Internal Nutrition

  • Importance of Nutrition:

    • Proper nutrition is vital for energy production, growth, and the repair of body tissues. It supports immune function and overall health status.

    • Gradual refeeding is critical for at-risk patients, especially those recovering from illness, to prevent complications such as refeeding syndrome and electrolyte imbalances.

  • Fluid, electrolyte imbalances are corrected

  • With nutrition, fluid & electrolyte imbalances are/can be corrected

  • Especially K, Mg, Ca, Acid-base balance

  • Gradual refeeding

  • Nutrition is reintroduced to pts

  • With refeeding, pts may have electrolyte imbalance

  • The hallmark for electrolyte imbalance for refeeding is the phosphorus (PO)

  • Enteral Nutrition:

    • Enteral nutrition involves the use of feeding tubes, such as nasogastric (NG) tubes, for patients who cannot eat by mouth but require nutritional support. This method allows for the direct delivery of calories and nutrients to the stomach.

    • With pts that need enteral nutrition, start feedings as early as possible

    • Complications of enteral feeding may include aspiration, diarrhea, and infection at the insertion site.

    • If your pt has aspirated, they will have a new onset of bilateral crackles & low O2 saturation

  • TPN Consideration:

    • Given via IV administration

    • Subclavian vein is used for a triple lumen (central line)

    • White port is saved for nutrition

    • ONLY use the saved port for TPN—nothing else goes in

    • Total Parenteral Nutrition (TPN) is a method of providing nutrition intravenously, bypassing the gastrointestinal tract entirely. It is critical that TPN is not mixed with other medications to avoid incompatibilities.

    • If TPN is delayed, dextrose solutions (like D10) may be administered temporarily to prevent hypoglycemia and maintain energy levels until full TPN can be resumed.

Chapter 6: Conclusion

  • Managing Nutrition:

    • It is essential for healthcare providers to always prioritize the nutritional needs of patients to avoid complications that may arise from malnourishment.

    • Quick and effective intervention is crucial for changes in a patient's nutritional status, particularly following surgery or during prolonged intravenous feeding.

  • Collaboration Required:

    • Effective communication among healthcare providers regarding patient nutrition management is vital, especially during emergencies or when there are delays in treatment. Collaboration ensures that patient needs are met consistently and effectively, optimizing nutrition care.