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Chapter 2 Nutritional Needs

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2 Chapter 2 Nutritional Needs
Note: This chapter covers the functions and sources of key nutrients; the effects of various nutrient deficiencies and excesses; and the processes of digestion, absorption, and metabolism. This presentation displays the text objective related to each of these topics, followed by information to help students achieve the objective. Part 1 The Importance of Food

3 Objective Discuss: What nutrients can you name? Why is it important to be aware of what nutrients do in your body and what foods provide them? Name the key nutrients, describe their functions, and list important sources of each. © 2002 Wisconsin Milk Marketing Board, Inc.

4 The Nutrients A nutrient is a chemical substance that helps maintain the body. You need over 50 nutrients, which can be divided into six groups. Carbohydrates Fats Proteins Vitamins Minerals Water Discuss: What have you heard about the health effects of any of these nutrient groups?

5 Key Nutrient: Carbohydrates
Functions Supply energy Provide bulk Help the body digest fats Spare proteins Discuss: Why do you need bulk in your diet? What is the value of sparing proteins?

6 Sources of Carbohydrates
Sugars—honey, jam Fiber sources—fruits, vegetables, whole grains Starch sources—breads, cereals, pasta Discuss: What do the terms simple carbohydrates and complex carbohydrates mean? Which type of carbohydrates should provide most of the calories in your diet? What is your favorite source of carbohydrates? photo courtesy of Fleischmann’s Yeast

7 Key Nutrient: Fats Functions Supply energy Carry fat-soluble vitamins
Insulate the body Protect organs Provide essential fatty acids Discuss: What functions do fats serve in foods?

8 Sources of Fats Saturated—dairy products, meats
Discuss: How do fats that are high in saturated fatty acids differ from those that are high in unsaturated fatty acids? How can you reduce the amount of saturated fats from dairy products and meats in your diet? What are some other food sources of mono- and polyunsaturated fats? Saturated—dairy products, meats Mono- and Polyunsaturated—fish, nuts, vegetable oils

9 Key Nutrient: Proteins
Functions Build and repair tissues Help body make important substances Regulate body processes Supply energy Discuss: Which of these functions is also performed by other nutrients?

10 Sources of Proteins Complete proteins—dairy products, eggs, fish, meat, poultry Incomplete proteins—beans, grains, nuts Discuss: Why are some sources of proteins considered to be “complete” while others are considered to be “incomplete”? What can you do to improve the nutritional value of incomplete sources of protein? How can you find out if a food is a good source of protein? National Chicken Council

11 Key Nutrient: Vitamins
Vitamins can be divided into two main groups. Fat-soluble vitamins dissolve in fats can be stored in fatty tissues of the body Water-soluble vitamins dissolve in water are not stored in the body Note: Each vitamin performs different specific functions. In general, vitamins support normal growth, maintenance of body tissues, and reproduction. Each vitamin is also found in different food sources. Eating a variety of foods is the best way to get all the vitamins you need.

12 Fat-Soluble Vitamins Nutrient Functions Sources Vitamin A Vitamin D
Keeps skin and mucus membranes healthy Prevents night blindness Promotes growth Butter, dark green and yellow fruits and vegetables, egg yolk, liver, whole and fortified milk Vitamin D Builds strong bones and teeth Egg yolk; fortified butter, margarine, and milk; the sun Vitamin E Acts as an antioxidant to protect cell membranes Eggs, liver, salad oils, whole grain cereals Vitamin K Helps blood clot Cauliflower, egg yolk, organ meats Note: Due to space limitations, not all functions and sources are listed. See Table 2-9 in the text for more detail. Discuss: What advantages and disadvantages are created by the body’s ability to store fat-soluble vitamins in the fatty tissues?

13 Water-Soluble Vitamins
Nutrient Functions Sources Vitamin C Helps wounds heal Helps fight infection Broccoli, citrus fruits, tomatoes Thiamin Keeps nervous system healthy Releases energy from food Pork, whole grain breads and cereals Riboflavin Helps cells use oxygen Breaks down carbohydrates Cheese, eggs, milk, poultry Niacin Helps cells use other nutrients Dried beans and peas, peanuts Folate Helps protect brain and spinal cord of unborn babies Bananas, fortified breads and cereals Note: Due to space limitations, not all functions and sources are listed. See Table 2-13 in the text for more detail. Other B-complex vitamins include vitamin B6, vitamin B12, pantothenic acid, and biotin. Discuss: What other nutrients are provided by the food sources of each of these vitamins?

14 Key Nutrient: Minerals
Minerals can be divided into two main groups. Macrominerals are needed in amounts of 100 mg or more per day. Trace elements are needed in amounts less than 100 mg per day. Note: Each mineral performs different specific functions. In general, minerals become part of the bones, soft tissues, and body fluids and help regulate body processes. Each mineral is also found in different food sources. Eating a variety of foods is the best way to get all the minerals you need. Discuss: What is another name for trace elements?

15 Macrominerals Nutrient Functions Sources Calcium Magnesium Phosphorus
Builds bones and teeth Helps muscles and nerves work Dairy products, leafy green vegetables Magnesium Helps cells use energy nutrients Regulates body temperature Beans, dark green leafy vegetables, whole grains Phosphorus Regulates bodily activities Protein and calcium food sources Sodium, chloride, potassium Control osmosis Maintain acid-base balance in the body Sodium and chloride: Table salt Potassium: Potatoes Note: Due to space limitations, not all functions and sources are listed. See Table 2-16 in the text for more detail. Discuss: Why is it especially important for teens to get adequate sources of calcium in their daily diets? What is the largest source of sodium and chloride in the U.S. diet?

16 Trace Elements Nutrient Functions Sources Fluorine Iodine Iron Zinc
Helps teeth resist decay Maintains bone health Fluoridated drinking water, toothpaste Iodine Promotes normal function of thyroid gland Iodized table salt, saltwater fish and shellfish Iron Helps cells use oxygen Dried beans and fruits, egg yolk, lean meats, whole grains Zinc Helps wounds heal Promotes normal growth Legumes, meat, poultry, seafood, whole grains Note: Due to space limitations, not all functions and sources are listed. See Table 2-18 in the text for more detail. Other trace elements include copper, selenium, and manganese. Discuss: Because they are needed in smaller amounts, do you think trace elements are less important for good health than macrominerals? Explain why or why not.

17 Key Nutrient: Water Functions
Aids digestion and cell growth and maintenance Facilitates chemical reactions Lubricates joints and cells Regulates body temperature Discuss: What factors would increase a person’s need for water?

18 Sources of Water Liquids Food Breakdown of energy nutrients
Discuss: What types of foods would have high water content? Which source do you think provides most of your water needs? Agricultural Research Service, USDA

19 Objective Discuss: Why is it important to consume the right balance of the various nutrients? Analyze the effects of various nutrient deficiencies and excesses.

20 Nutrient Deficiencies
Failure to get a sufficient amount of a nutrient may result in an illness called a deficiency disease. Such diseases include protein-energy malnutrition (protein) night blindness (vitamin A) rickets (vitamin D) scurvy (vitamin C) osteoporosis (calcium) Discuss: What other nutrient deficiency diseases can you name?

21 Nutrient Excesses Discuss: If nutrients are good for you, why wouldn’t consuming more of them always be better for you? Excess energy nutrients—carbohydrates, fats, and proteins—can lead to unhealthful weight gain. Excesses of some vitamins and minerals can lead to toxicity (poisoning) and other complications.

22 Apply It! Your grandmother has been diagnosed with osteoporosis.
Discuss: What steps can you take now to avoid developing osteoporosis as you age? What is the likely cause of this affliction? What health effects may your grandmother suffer as a result of this disease?

23 Objective Discuss: What can you do to help your body digest foods and use the nutrients they provide? Explain the processes of digestion, absorption, and metabolism.

24 The Digestion Process Digestion is the bodily process of breaking food down into simpler compounds the body can use. The mechanical phase involves the physical breakdown of food caused by chewing and muscle activity in the digestive tract. The chemical phase involves the chemical breakdown of food caused by enzymes in saliva and digestive juices. Discuss: What parts of your body are involved in the digestion process?

25 The Absorption Process
Absorption is the process of taking in nutrients and making them part of the body. A large surface area in the small intestine allows tiny nutrient particles to pass into the blood and lymph systems and travel where needed. Discuss: How must carbohydrates, fats, and proteins be broken down before the body can absorb them? What would happen if your body were unable to absorb the nutrients you consumed through foods?

26 Metabolism Metabolism is the chemical processes that take place in the cells after the body absorbs nutrients. Carbohydrates are converted into glucose for use as an energy source. Fatty acid chains from fats are shortened and fats are used for fuel. Amino acids from proteins are used for maintenance, growth, production of enzymes and antibodies, and energy. Discuss: What roles do vitamins, minerals, and water play in metabolism?

27 What are your nutritional needs?
Key Question Note: Encourage students to use this question to help them review chapter information and apply it to their lives. What are your nutritional needs?

28 Other Questions to Consider
Discuss: What other questions did this chapter raise that you would like to explore? What role should dietary supplements play in meeting nutrient needs? What is cholesterol and why is it a nutritional concern?

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