2. 2
Nutritional Needs

3. Objectives
Name the key nutrients, describe their functions, and list important sources of each.
Analyze the effects of various nutrient deficiencies and excesses.
Explain the processes of digestion, absorption, and metabolism.

4. The Nutrients
Food provides nutrients, which are necessary for good health
Nutrition examines how the body uses nutrients
If you do not eat the foods your body needs, you may suffer from malnutrition
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5. The Nutrients Nonessential nutrients are substances the body can make
Essential nutrients are substances the body cannot make and must be supplied by the foods you eat
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6. The Nutrients There are six main groups of essential nutrients:
carbohydrates
fats
proteins
vitamins
minerals
water
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7. The Nutrients
Failure to get enough of the needed nutrients may result in a deficiency disease
Consuming too much of some nutrients can result in toxicity

8. Dietary Supplements
Doctors may recommend dietary supplements to help make up for nutrient shortages in the diet
Some dietary supplements provide nonnutrient substances, such as herbs and some antioxidants
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9. Dietary Supplements
Besides supplements, fortified foods can be a source of added nutrients
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10. Carbohydrates Carbohydrates are the body’s main energy source
They are classified as simple or complex based on molecular structure
They are carried through the bloodstream in the form of glucose
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11. Functions of Carbohydrates
Carbohydrates are sources of energy for the body and brain
Fiber does not provide energy, but can help
reduce the risk of heart disease
speed food through the body
dilute carcinogens (cancer-causing agents)
reduce the risk of cancer

12. Sources of Carbohydrates
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Sugars, soft drinks, and candies are sources of simple carbohydrates
Breads and cereals provide starches
Fruits, vegetables, and whole grains offer fiber

13. Carbohydrate Deficiencies and Excesses
A carbohydrate deficiency can cause the body to use protein as an energy source
This can interfere with the normal growth and repair of body tissues and potentially create a chemical imbalance
Consuming too many simple carbohydrates can result in nutrient shortages and excess calories

14. Fats Fats belong to a group of compounds called lipids
Lipids, which include both fats and oils, contain fatty acids
Based on the amount of hydrogen atoms found in their molecules, fatty acids are classified as saturated or unsaturated

15. Types of Fats
Saturated fatty acids have as many hydrogen atoms as they can hold
Unsaturated fatty acids have fewer hydrogen atoms than they can hold
monounsaturated
polyunsaturated
Hydrogenation makes unsaturated fatty acids saturated and creates trans fatty acids
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16. Types of Fats
Cholesterol is a fatlike substance that serves important functions in the body
Part of skin tissue
Aids in transport of fatty acids
Produces hormones

17. Think Further Why don’t you need to add cholesterol to your diet?
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18. Functions of Fats Supply energy Carry certain types of vitamins
Enhance flavor in foods
Tenderize meats and baked goods
Protect organs
Insulate the body

19. Sources of Fats Eggs Dairy products Meats Fish Nuts Vegetable oils
Olives
Avocados
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20. Fat Deficiencies and Excesses
A diet low in fat may result in a loss of weight and energy
Diets high in fat have been linked to heart disease, some cancers, and weight gain
No more than 35 percent of the calories in your daily diet should come from fat
No more than 10 percent of total calories should come from saturated fat

21. Proteins
Proteins, the third category of essential nutrients, are made of amino acids
Essential amino acids
Nonessential amino acids
Complete proteins contain all nine essential amino acids
Incomplete proteins are missing one or more of the essential amino acids

22. Functions of Proteins Growth, maintenance, and repair of tissues
Formation of enzymes, some hormones, and antibodies
Source of energy
Regulation of bodily processes

23. Sources of Proteins Meat Poultry Fish Dairy products Eggs Dried beans
Nuts
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24. Protein Deficiencies and Excesses
A protein deficiency can lead to protein-energy malnutrition (PEM)
Excess protein in the diet will be converted to fat

25. In Your Opinion… What is your favorite source of protein?
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26. Vitamins Each vitamin serves unique functions
The body cannot produce most vitamins in quantities large enough to meet nutritional needs
A varied, nutritious diet is best to get the vitamins the body needs
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27. Vitamins Fat-soluble vitamins Water-soluble vitamins vitamin A
vitamin D
vitamin E
vitamin K
Water-soluble vitamins
vitamin C
thiamin
riboflavin
niacin
vitamin B6
folate
vitamin B12
pantothenic acid
biotin

28. Fat-Soluble Vitamins Vitamin A
aids the eyes with ability to see at night
promotes bone growth
keeps skin and other tissues healthy
found in liver, egg yolk, and whole milk
has higher values in orange and dark green fruits and vegetables
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29. Fat-Soluble Vitamins Vitamin D
promotes the growth and mineralization of bones and teeth
found in eggs, liver, and fatty fish
used to fortify most milk, cereal, and margarine
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30. Fat-Soluble Vitamins Vitamin E acts as an antioxidant
protects red and white bloods cells, fatty acids, and vitamin A
common in many food items, including fats and oils, whole-grain products, liver, eggs, whole milk dairy foods, and leafy green vegetables
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31. Fat-Soluble Vitamins Vitamin K aids in blood clotting
produced in the intestinal tract
found in leafy green vegetables, cauliflower, organ meats, and egg yolk
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32. Water-Soluble Vitamins
Vitamin C (ascorbic acid)
helps form and maintain collagen, which holds body cells together
firms the walls of blood vessels
helps heal wounds and broken bones
helps create hemoglobin and fight infections
functions as a dietary antioxidant
found in many fresh fruits and vegetables
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33. Water-Soluble Vitamins
B-complex vitamins work together in the body
thiamin
riboflavin
niacin
vitamin B6
folate
vitamin B12
biotin
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34. Water-Soluble Vitamins
Thiamin (B1)
helps the body release energy from food and promote normal appetite and digestion
found in nearly all foods except fats, oils, and refined sugars
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35. Water-Soluble Vitamins
Riboflavin (B2)
helps break down carbohydrates
helps cells use oxygen
keeps skin, tongue, and lips healthy
found in milk, eggs, oysters, leafy green vegetables, and whole-grain enriched cereal products
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36. Water-Soluble Vitamins
Niacin
helps keep the nervous system, mouth, skin, tongue, and digestive tract healthy
helps cells use nutrients
found in meats, poultry, and peanuts
too much niacin can cause nausea, vomiting, and red flushing
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37. Water-Soluble Vitamins
Vitamin B6
helps nerve tissues function normally
aids with the regeneration of red blood cells
helps break down proteins, carbohydrates, and fats
found in vegetables, muscle meats, and whole-grain cereals
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38. Water-Soluble Vitamins
Folate
helps the body produce normal blood cells
folic acid is especially important during pregnancy
found in green vegetables, yogurt, fruits, and whole-grain cereals
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39. Water-Soluble Vitamins
Vitamin B12
promotes normal growth
aids in normal functioning of cells in bone marrow, nervous system, and intestines
found in animal protein foods and cereals
Pantothenic Acid
helps the body use energy nutrients and make cholesterol
promotes growth
found in plant and animal tissues, yeast, and milk
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40. Water-Soluble Vitamins
Biotin
aids in the breakdown of fats, carbohydrates, and proteins
essential part of several enzymes
found in kidney, liver, chicken, eggs, milk, fresh vegetables, and some fruits
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41. Vitamin Deficiencies and Excesses
Vitamin deficiencies can result in such conditions and diseases as night blindness, rickets, scurvy, beriberi, pellagra, and anemia

42. Did You Know?
The term vitamin was originally vitamine, a combination of the words vita and amine. Vita is Latin for life. Amine referred to amino acids, which scientists initially thought were part of the make up of vitamins. The final e was later dropped when scientists learned that vitamins did not contain amino acids.

43. Minerals
The body needs at least 21 minerals for good health, which can be obtained from a variety of foods
Macrominerals are needed in large quantities per day
Trace elements, or microminerals, are needed in smaller quantities per day

44. Macrominerals Calcium
combines with phosphorous to build and strengthen bones and teeth
helps blood clot
keeps the heart and nerves working properly
found in milk, fish, and green vegetables
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45. Macrominerals Phosphorous works with calcium to build bones and teeth
helps the body store and release energy
found in meat, poultry, eggs, milk, and dairy products
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46. Macrominerals Magnesium helps regulate the body’s temperature
keeps the nervous system working properly
found in whole grains and grain products, nuts, beans, meats, and dark green leafy vegetables
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47. Macrominerals Sodium, chloride, and potassium
work as a team to control osmosis
help the nervous system and muscles function
help cells absorb nutrients
common in the food supply and U.S. diet
sources include table salt, many types of seafood, many vegetables, and fruits

48. Trace Elements Iron Zinc
helps form hemoglobin, which carries oxygen throughout the body
found in animal sources and leafy green vegetables
Zinc
aids the immune system
promotes normal growth and development
found in meats and whole grains
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49. Trace Elements Fluoride Iodine helps teeth develop and resist decay
may maintain bone health
found in water
Iodine
helps regulate energy usage rate
found in seafood and iodized salt
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50. Mineral Deficiencies and Excesses
Mineral deficiencies can cause such conditions as osteoporosis and goiter
Research has shown there is a link between excess sodium amounts and hypertension
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51. Think Further
Why do you need to vary your diet in order to consume the essential nutrients?
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52. Water Water is the sixth essential nutrient
Between 50 and 75 percent of body weight is water
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53. Functions of Water
Water aids digestion, cell growth and maintenance, chemical reactions, joint lubrication, and temperature regulation in the body
Nearly all beverages and foods provide some water

54. Water Intake and Excretion
About 80 percent of water intake comes from liquids
The body excretes most water through the kidneys as urine and the remaining through the skin, lungs, and feces
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55. Water Requirements
Most people should consume about 1 ounce of fluid for every 2 pounds of body weight
Climate, health, and eating habits affect water needs
Thirst is the first symptom of water loss
Too much water can result in water intoxication, a rare condition

56. Digestion and Absorption
Foods must go through the processes of digestion and absorption before the body can use the nutrients they contain
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57. The Digestive Tract
The digestive or gastrointestinal tract is about 30 feet long
esophagus
stomach
small intestine
large intestine
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58. The Digestion Process Mechanical phase
begins in the mouth when teeth chew food and break it down into smaller pieces
initiates contractions in the digestive tract, known as peristalsis
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59. The Digestion Process Chemical phase
begins in the mouth when food mixes with saliva
gastric juices break down food in the stomach
the semiliquid leaves the stomach and enters the small intestine, where intestinal juices, pancreatic juices, and bile act on the food
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60. The Digestion Process
digestive enzymes help break foods down into simple substances the body can absorb and use
once digestion is complete, absorption can take place
some substances then travel into the large intestine, which acts as a reservoir
the body excretes these materials in the feces

61. The Absorption Process
Most absorption takes place in the small intestine
The small intestine is lined with millions of villi, which aid in absorption
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62. Metabolism
Metabolism takes place in the cells after the body absorbs nutrients
Nutrients follow a distinct metabolic path
Carbohydrates become glucose for energy or glycogen for storage
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63. Metabolism During fat metabolism, fats become fuel
During protein metabolism, amino acids are used for cell maintenance and growth or as energy

64. Review What are the six essential nutrients? carbohydrates fats
proteins
vitamins
minerals
water

65. Review 2. What is one function of each of the key nutrients?
Answers will vary.
3. What are two important sources of each of the key nutrients?

66. Review
4. How can deficiencies and excesses of various nutrients affect the body?
nutrient deficiencies can result in deficiency diseases, protein-energy malnutrition, night blindness, rickets, scurvy, beriberi, pellagra, anemia, osteoporosis, hypertension, and goiter; nutrient excesses can result in toxicity

67. Review
5. What occurs in the body during the processes of digestion, absorption, and metabolism?
digestion breaks food down into simple materials the body can use; absorption involves taking in nutrients and making them part of the body; metabolism involves chemical processes that take place in the cells after the body absorbs nutrients

68. Glossary
absorption. The process of taking nutrients into the body and making them part of the body.
amino acid. A chemical compound that serves as a building block of proteins.
anemia. A condition resulting from deficiencies of various nutrients, which is characterized by a reduced number of red blood cells in the bloodstream.

69. Glossary
antioxidant. A substance that prevents or slows down damage caused by chemical reactions involving oxygen.
beriberi. A disease of the nervous system resulting from a thiamin deficiency, which is characterized by numbness in the ankles and legs followed by severe cramping and paralysis and potentially fatal heart disturbances.

70. Glossary
carbohydrate. One of the six basic types of nutrients that is the body’s chief source of energy.
cholesterol. A fatlike substance that occurs naturally in the body and is found in every cell. It occurs only in foods of animal origin.

71. Glossary
deficiency disease. An illness caused by the lack of a sufficient amount of a nutrient.
dietary supplement. A purified nutrient or nonnutrient substance that is manufactured or extracted from natural sources.

72. Glossary
digestion. The bodily process of breaking food down into simpler compounds the body can use.
fat. One of the six basic types of nutrients that is an important energy source belonging to a larger group of compounds called lipids.

73. Glossary
fat-soluble vitamin. A vitamin that dissolves in fats and can be stored in the fatty tissues of the body.
fatty acid. A chemical chain containing carbon, hydrogen, and oxygen that is the basic component of all lipids.
fiber. A form of complex carbohydrate from plants that humans cannot digest.

74. Glossary
fortified food. A food to which nutrients are added in amounts greater than what would naturally occur in the food.
glucose. The form of sugar carried in the bloodstream for energy use throughout the body.
goiter. A visible enlargement of the thyroid gland resulting from an iodine deficiency.

75. Glossary
hydrogenation. A process by which hydrogen atoms are chemically added to unsaturated fatty acids in liquid oils to turn the oils into more highly saturated solid fats.
hypertension. High blood pressure.
macromineral. A mineral needed in the diet in amounts of 100 or more milligrams each day.

76. Glossary
malnutrition. A lack of the right proportions of nutrients over an extended period, which can be caused by an inadequate diet or the body’s inability to use the nutrients from foods.
metabolism. The chemical processes that take place in the cells after the body absorbs nutrients.

77. Glossary
mineral. One of the six basic types of nutrients that is an inorganic substance and becomes part of the bones, soft tissues, and body fluids.
night blindness. A condition resulting from a vitamin A deficiency, which is characterized by a reduced ability to see in dim light.

78. Glossary
nutrient. A chemical substance from food the body needs to live.
nutrition. The study of how the body uses the nutrients in foods that are eaten.
osteoporosis. A condition resulting from a calcium deficiency, which is characterized by porous, brittle bones.

79. Glossary
pellagra. A disease resulting from a niacin deficiency that is characterized by skin lesions and digestive problems. Mental disorders and death may follow if left untreated.
peristalsis. Waves of muscle contractions that push food through the digestive tract.

80. Glossary
protein. One of the six basic types of nutrients, made up of amino acids, that is required for growth, repair, and maintenance of every body cell.
protein-energy malnutrition (PEM). A condition that may result from a diet that does not contain enough protein and calories.

81. Glossary
rickets. A disease resulting from a vitamin D deficiency, which is characterized by crooked legs and misshapen breast bones in children, and bone abnormalities in adults.
saliva. A mucus- and enzyme-containing liquid secreted by the mouth that makes food easier to swallow and begins to break down starches.

82. Glossary
scurvy. A disease resulting from a vitamin C deficiency, which is characterized by bleeding gums, loss of teeth, and internal bleeding.
toxicity. Poisoning.
trace element. A mineral needed in the diet in amounts less than 100 milligrams per day.

83. Glossary
trans fatty acid. A fatty acid with an odd molecular shape that is created in hydrogenated oils and found naturally in dairy products, beef, and lamb.
vitamin. One of the six basic types of nutrients that is a complex organic substance needed by the body in small amounts for normal growth, maintenance, and reproduction.

84. Glossary
water-soluble vitamin. A vitamin that dissolves in water and is not stored in the body to any great extent.