Introduction to nutrition


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Introduction to nutrition

  1. 1. Introduction to Nutrition
  2. 2. Learning Objectives:  Consider factors that influence food selection  Define nutrition, calorie, nutrient, and nutrient density  Identify the classes of nutrients and their characteristics  Describe the 4 characteristics of a nutritious diet
  3. 3. Learning Objectives  Define Dietary Reference Intakes  Compare and contrast the EAR, RDA, AI and UL  Explain the importance and function of the Dietary Reference Intakes  Describe the processes of digestion, absorption and metabolism, and how the digestive system works
  4. 4. Factors Influencing Food Selection Values or beliefs Cultural background and religious beliefs Age, gender, occupation, education and income
  5. 5. Factors Influencing Food Selection  Family influences  Social influences  Emotional influences
  6. 6. Factors Influencing Food Selection     Peer pressure Familiarity with the food What you associate the food with (ex. Cakes for birthdays) Nutritional value of the food
  7. 7. Factors Influencing Food Selection    How the food smells, looks and tastes Cost, convenience and availability of the food Your nutritional knowledge and concerns
  8. 8. Factors Influencing Food Selection    Desire to improve your health The media, including advertising Environmental concerns
  9. 9. Nutrition  A science that studies nutrients and other substances in food and how these nutrients relate to health and diseases  Explores why you choose particular foods and the type of diet you eat
  10. 10. Nutrients  The nourishing substances in food that provide energy and promote the growth and maintenance of your body  Diet: the food and beverages that you normally eat
  11. 11. Calories      A measure of the energy in food, specifically the energy-yielding nutrients Based on 3 factors: Basal metabolism Physical activity Thermic effect of food
  12. 12. Factors that Affect Basal Metabolism  Gender: higher in men  Age: declines 2-3% per decade  Growth: higher in children, pregnant women and lactating women
  13. 13. Factors that Affect Basal Metabolism    Height: Tall thin people have higher BMR Temperature: increases in both hot and cold environments Fever and stress: increase BMR
  14. 14. Physiologic Fuel Value  1 g carbohydrate = 4 kcal  1 g fat = 9 kcal  1 g protein = 4 kcal  1 g alcohol = 7 kcal
  15. 15. Essential Nutrients for Human Nutrient Examples Fat Linoleic and Linolenic Acid Carbohydrate Glucose and Dietary Fiber Protein Vitamins Minerals Water Amino Acids : Arginine, Histidine, Isoleucine, Leucine, Lysine, Methionine, Phenylalanine, Threonine, Tryptophan, Valine Fat-soluble : A, D, E and K Water-soluble : Thiamin, Riboflavin, Niacin, Folic Acid, Cobalamin, Pyridoxine, Pantothenic Acid, Biotin and Ascorbic Acid Ca, P, Mg, S, Na, Cl, K, Fe, Cu, Mn, Zn, Co, I, Mo, Se, Cr, Fl
  16. 16. Nutrient Density  A measure of the nutrients provided in a food per calorie of the food
  17. 17. Characteristics of a Nutritious Food  Adequate  Balanced  Moderate  Varied
  18. 18. Dietary Reference Intakes  Reference values that are quantitative estimates of nutrient intakes to be used for planning and assessing diets for apparently healthy people
  19. 19. Estimated Average Requirement (EAR)  The daily dietary intake level that is estimated to meet the nutrient requirement of 50% of healthy individuals in a particular life stage and gender group
  20. 20. Recommended Dietary Allowance  The standard deviation indicates the degree of variation from the mean; in this case, it indicates how different the nutrient requirements of individual group members are from the group mean
  21. 21. Adequate Intake (AI) An observational standard that is used when insufficient data is available to determine an RDA from an existing EAR  Because it is set using presumable healthy groups of individuals, the AI is expected to meet or exceed the actual nutrient requirement in all healthy members of a specific life stage and gender group 
  22. 22. Tolerable Upper Level  The highest level of daily nutrient intake that is likely to pose no risk of adverse health effects to almost all apparently healthy individuals in the general population  As intake increases above the UL, the risk of adverse (toxic) effects increases
  23. 23.  Digestion : the process by which food is broken down to absorbable units.  Gastrointestinal tract : flexible muscular tube from the mouth through the esophagus, stomach, small intestine, large intestine, and the rectum to the anus.  Absorption : the passage of nutrients from the GI tract into either the blood or the lymph.
  24. 24.    Mouth : the oral cavity containing the tongue and teeth. Pharynx : the passageway leading from the nose and mouth to the larynx and esophagus, respectively. Epiglottis : cartilage in the throat that guards the entrance to the trachea and prevents fluid or food from entering it when the person swallows.
  25. 25.    Esophagus : the food pipe; the conduit from the mouth to the stomach. Sphincter : a circular muscle surrounding, and able to close a body opening. Sphincters are found at specific points along the GI tract and regulate the flow of food particles. Stomach : a muscular, elastic, saclike portion of the digestive tract that grinds and churns swallowing good, mixing it with acid and enzymes to form chime.
  26. 26.    Pyloric sphincter : the circular muscle that separates the stomach from the small intestine and regulates the flow of partially digested food into the small intestine. Gallbladder : the organ that stores and concentrates bile. When it receives the signal that fat is present in the duodenum, the gallbladder contracts and squirts bile through the bile duct into the duodenum. Pancreas : a gland that secretes digestive enzymes and juices into the duodenum.
  27. 27.  Small intestine : a 10-ft length of smalldiameter intestine that is the major site of digestion of food and absorption of nutrients. Its segments are the duodenum, jejunum and ileum.  Lumen : the space within a vessel, such as the intestine.
  28. 28.  Duodenum : the top portion of the small intestine  Jejunum : the first two-fifths of the small intestine beyond the duodenum.  Ileum : the last segment of the small intestine.  Ileocecal valve : the sphincter separating the small and large intestines.
  29. 29.    Large intestine (colon): the lower portion of the small intestine that completes the digestion process. Its segments are the ascending colon, the transverse colon, the descending colon and the sigmoid colon. Rectum : the muscular terminal part of the intestine, extending from the sigmoid colon to the anus. Anus : the terminal outlet of the GI tract.