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Nutrition

Nutrition. Chapter 15a. All the chemical reactions in a person’s body constitute that person’s metabolism. Catabolic processes break down nutrients to obtain energy & raw materials. Anabolic processes use energy to assemble cells & tissues.

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Nutrition

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  1. Nutrition Chapter 15a

  2. All the chemical reactions in a person’s body constitute that person’s metabolism Catabolic processes break down nutrients to obtain energy & raw materials Anabolic processes use energy to assemble cells & tissues

  3. The calorie is a measure of the amount of energy in food How calories can be measured • The calorie is the metric unit of energy, the amount of energy necessary to raise the temperature of 1 mL of water by 1oC • Though they are still called “calories”, food calories, or Calories, are actually kilocalories, equal to 1000 regular calories

  4. 1. All living things are composed of 4 common macromolecules • Nucleic Acids • Proteins • Carbohydrates • Lipids • DNA is a nucleic acid

  5. Nucleic acids and Proteins Nucleic acids- DNA Proteins, made of amino acids

  6. Carbohydrates and Lipids Carbohydrates- glucose+ fructose= sucrose Lipids- a fat molecule made of glycerol and 3 fatty acids

  7. Vitamins and Minerals • There are 13 vitamins, and various minerals which the body must obtain through diet • Vitamins and minerals often function as cofactors in enzymes • Because cofactors are recycled, vitamins are required in minute quantities

  8. Human metabolism is diverse but limited • Though the body can manufacture many of its own necessary parts, essential nutrients cannot be manufactured and must be obtained through diet • Essential amino acids are required to make all proteins • Essential fatty acids are required for cell signaling

  9. Nutrients • Food provides • Fuel for cellular activities • Metabolic regulators • Building blocks for • Cell division • Maintenance • Repair

  10. We also need water… • Water is necessary for • Proper cellular environments • Certain cellular reactions

  11. Nutrients • A nutrient is a substance in food that • Provides energy • Plays a structural or functional role to promote normal growth, maintenance, or repair

  12. Lipids

  13. Lipids • Lipids • Fats • Oils • Cholesterol • 95% of the lipids found in food are triglycerides • Consist of a molecules made from three fatty acids attached to a molecule of glycerol

  14. Lipids • Fat • A ready source of energy • Insulation and a cushion for vital organs • Components of the cell membrane • Construction of myelin sheaths • Absorption of fat-soluble vitamins

  15. Lipids • Fatty acids differ in their degree of saturation • Saturated fats • Solid at room temperature • Most come from animal sources • Unsaturated fats • Liquid at room temperature • Come from plant sources

  16. Lipids • A high-fat diet is associated with • Obesity • High blood pressure • Atherosclerosis • Increased risk of diabetes • Certain cancers • E.g., colon, prostate, lung

  17. Cholesterol • Cholesterol • The structural basis for the steroid hormones • Low-density lipoproteins (LDLs) • Bad • They deposit cholesterol in the artery walls • High-density lipoproteins (HDLs) • Good • They help the body to eliminate cholesterol

  18. Fats in the diet • Only 20 to 30% of the calories in the diet should come from fats • Most of those should be monounsaturated and polyunsaturated fats

  19. Carbohydrates

  20. Carbohydrates • Carbohydrates • Provide fuel for our bodies • Found in our diet as sugars, starches, and fiber

  21. Carbohydrates • Dietary fiber • A carbohydrate in plant foods that humans cannot digest • Good for the heart and blood vessels • It lowers LDLs but does not lower the beneficial HDLs

  22. Carbohydrates • 45 to 65% of the calories in our diet should come from carbohydrates, including both • Simple carbohydrates • Sugars • Complex carbohydrates • Starches and fiber

  23. Figure 15a.3

  24. Carbohydrates • The glycemic response • A measure of how quickly a serving of food is converted to blood sugar • The glycemic index • A numerical ranking of carbohydrates based on their glycemic response • Foods with a low glycemic index help to reduce the risk of heart disease and diabetes

  25. Proteins

  26. Proteins • Proteins • The structural components of every cell • Regulate body processes • Are antibodies • Can be used for energy

  27. Proteins • Proteins • Chains of amino acids that are digested and delivered to the cells • Human proteins contain 20 different kinds of amino acids • The human body can synthesize 11 of the amino acids • The remaining 9 must be supplied by the diet • Essential amino acids

  28. Proteins • Complete dietary proteins • Contain all 9 of the essential amino acids that your body cannot synthesize • Incomplete proteins • Lack one or more of the essential amino acids

  29. Proteins • Complementary proteins • Combinations of proteins that together supply enough of all the essential amino acids

  30. Proteins • 10 to 35% of the calories in our diet should come from a combination of plant and animal proteins

  31. Vitamins and Minerals

  32. Vitamins & Minerals • Vitamins • Organic compounds that are needed in minute quantities • Usually function as coenzymes

  33. Vitamins Table 15a.2 (1 of 2)

  34. Table 15a.2 (2 of 2)

  35. Nutrients • Vitamins • Water-soluble • Fat-soluble • Except for vitamin D, our cells cannot make vitamins and must obtain them from food

  36. Nutrients • Minerals are inorganic substances that are essential to a healthy diet

  37. Minerals Table 15a.3 (1 of 2)

  38. Minerals Table 15a.3 (2 of 2)

  39. Water • Water • Transports materials through our blood and lymph • Provides a medium for chemical reactions • Is a lubricant • Can serve as a protective cushion • Plays an important role in the regulation of body temperature

  40. Nutrition and Weight Control • MyPyramid is a food guide for planning a healthy diet • Nutrients provide energy or have a structural or functional role in the body • Food labels help us make wise food choices • For body energy balance, calories gained in food must equal calories used

  41. MyPyramid Is a Food Guide for Planning a Healthy Diet • MyPyramid • A food guide released by the U.S. Department of Agriculture (USDA) in 2005 for planning a healthy diet

  42. MyPyramid Is a Food Guide for Planning a Healthy Diet Figure 15a.1

  43. MyPyramid Is a Food Guide for Planning a Healthy Diet Figure 15a.1 (1 of 2)

  44. MyPyramid Is a Food Guide for Planning a Healthy Diet Figure 15a.1 (2 of 2)

  45. MyPyramid Is a Food Guide • A healthy lifestyle includes • Choosing food wisely • Staying within your calorie needs • Engaging in physical activity

  46. Food Labels Help Us Make Wise Choices • Using the information on food labels can help you make healthy choices and compare different brands and ingredients

  47. Food Labels Help Us Make Wise Choices Figure 15a.6 (1 of 2)

  48. Food labels can be misleading Figure 15a.6 (2 of 2)

  49. Body Energy Balancing • Body’s energy balance depends on • The calories gained in food • The calories used • Unused food energy is stored • Fat • Glycogen

  50. Body Energy Balancing • The body requires energy for maintenance of • Basic body functions • Basal metabolic rate (BMR) • Physical activity • Processing of the food that is eaten

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