nfmnt chapter 3 digestion, absorption, and utilization of nutrients

Nutrition Fundamentals and Medical Nutrition Therapy

Digestion, Absorption, and Utilization of NutrientsCorresponds with LEARNING PLAN 3Copyright 2016 Association of Nutrition and Foodservice Professionals

3

Objectives

Follow the path of digestion

Relate digestion to nutrition

Describe the organs involved in digestion

Differentiate between digestion of protein, fat, and types of carbohydrates

Discuss absorption and its relationship to other body systems

Explain the concepts of absorption and availability of nutrients

Nutrition Fundamentals and Medical Nutrition Therapy • Digestion, Absorption, and Utilization of Nutrients • Learning Plan 3

Follow the Path of Digestion

The digestive system» One of many ‘systems’ in our body» Organs body tissues cells » Specific cells perform specific functions» Organs work together as part of body systems

Nutrition Fundamentals and Medical Nutrition Therapy • Digestion, Absorption, and Utilization of Nutrients • Learning Plan 3

How the Digestive System Works

GI tract is made up of a 30’ long looped tube from mouth to anus

Digestion» Breaks food into smaller components» Converts components into nutrients» Eliminates solid wastes

Several organs involved in the digestive process» Smooth muscle layer helps food move through the tract

Nutrition Fundamentals and Medical Nutrition Therapy • Digestion, Absorption, and Utilization of Nutrients • Learning Plan 3

Brain Break

Identify the location of the organs involved in digestion.

Nutrition Fundamentals and Medical Nutrition Therapy • Digestion, Absorption, and Utilization of Nutrients • Learning Plan 3

Brain Break

Nutrition Fundamentals and Medical Nutrition Therapy • Digestion, Absorption, and Utilization of Nutrients • Learning Plan 3

Food is Broken Down During Digestion Mechanical breakdown

» Physical breakdown of food into smaller pieces- Chewing- 32 permanent teeth to grind and breakdown food

Chemical breakdown» Digestive enzymes chemical reactions breakdown of

complex nutrients

Nutrition Fundamentals and Medical Nutrition Therapy • Digestion, Absorption, and Utilization of Nutrients • Learning Plan 3

Path of Digestion

Mouth» Tongue and saliva form a bolus (mass of food)» Swallowing (from mouth to esophagus)

- Involuntary- Epiglottis prevents food from entering lungs

Esophagus» Lower Esophageal Sphincter (LES)

- Where acid reflux from the stomach can occur when the sphincter doesn't work properly

Nutrition Fundamentals and Medical Nutrition Therapy • Digestion, Absorption, and Utilization of Nutrients • Learning Plan 3

Path of Digestion

Stomach» Muscular contractions called peristalsis» Churns food into liquid consistency (chyme)» Alcohol and aspirin are absorbed

Small intestine» Chyme arrives through pyloric sphincter

Nutrition Fundamentals and Medical Nutrition Therapy • Digestion, Absorption, and Utilization of Nutrients • Learning Plan 3

Path of Digestion

Small intestines » 20’ long» Three parts

- Duodenum, jejunum, ileum

Nutrition Fundamentals and Medical Nutrition Therapy • Digestion, Absorption, and Utilization of Nutrients • Learning Plan 3

duodenumjejunum ileum

Brain Break

If a person no longer has a gallbladder, the digestion of what nutrient may be affected?

» Fat

Nutrition Fundamentals and Medical Nutrition Therapy • Digestion, Absorption, and Utilization of Nutrients • Learning Plan 3

Path of Digestion

Large intestine or colon» Extends from end of the ileum to the rectum» Water and some minerals absorbed here» Healthful bacteria is essential» Receives and stores waste products from digestion» Indigestible fiber attracts and holds water» Waste products released as solid feces through anus

Nutrition Fundamentals and Medical Nutrition Therapy • Digestion, Absorption, and Utilization of Nutrients • Learning Plan 3

Digestion of Nutrients

Carbohydrate» Mouth and small intestine

Protein» Stomach and small intestine

Fats» Small amount in mouth and stomach» Primarily in small intestine

Insoluble fiber» No digestive action

Nutrition Fundamentals and Medical Nutrition Therapy • Digestion, Absorption, and Utilization of Nutrients • Learning Plan 3

Absorption

Nutrients must pass from GI tract to circulatory system» Blood» Lymph

Metabolism» Anabolism – building substances» Catabolism – breaking down substances

Bioavailability of nutrients» How well nutrients are absorbed and used by the body

Nutrition Fundamentals and Medical Nutrition Therapy • Digestion, Absorption, and Utilization of Nutrients • Learning Plan 3

Brain Break

If a person has a GI illness, what might be a concern for the Certified Dietary Manager?

» The client may not be able to absorb nutrients adequately or bioavailability of nutrients may be decreased.

Nutrition Fundamentals and Medical Nutrition Therapy • Digestion, Absorption, and Utilization of Nutrients • Learning Plan 3