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208
Chapter 12 – Water and the Major Minerals
Learning Objectives
After completing Chapter 12, the student will be able to:
12.1 Explain how the body regulates fluid balance.
a. List the uses of water in the body.
12.3 Identify the main roles, deficiency symptoms, and food sources for each of the major minerals (sodium,
chloride, potassium, calcium, phosphorus, magnesium, and sulfate).
12.4 Describe factors that contribute to the development of osteoporosis and strategies to prevent it.
a. Discuss osteoporosis, including bone development and disintegration.
Assignments and Other Instructional Materials
The following ready-to-use assignments are available in this chapter of the instructor’s manual:
• Case Study 12-1: Fluid and Calcium for a Young Athlete
• New! Case Study 12-2: Recipe Modification for Sodium Control
• Worksheet 12-1: Facts about Water (Internet Exercise)1
Other instructional materials in this chapter of the instructor’s manual include:
• Answer keys for How To (pp. 380, 389) activities and study card questions
Lecture Presentation Outline4
Key to instructor resource annotations (shown to the right of or below outline topics):
TRA = Transparency acetates: 13e = 13th edition, 12e = 12th edition, 11e = 11th edition, 10e = 10th edition
Website = Available for download from book companion website: HN = student handout
IM = Included in this instructor’s manual: CS = case study, WS = worksheet, CA = classroom activity
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Introductory/whole chapter resources: PL figure JPEGs; Test Bank; IM WS 12-5, CA 12-4
I. Water and the Body Fluids IM WS 12-1
A. Water’s roles – Discuss the roles of water in the body
B. Water Balance and Recommended Intakes
1. Intracellular and extracellular fluids (Figure 12-1)
2. Water Intake
3. Water sources
a. Liquids – 550 to 1500 mL
b. Foods – 700 to 1000 mL
c. Metabolic water – 200 to 300 mL
4. Water Losses
a. Kidneys – 500 to 1400 mL
b. Skin – 450 to 900 mL
f. Both caffeine and alcohol can have a diuretic effect
6. Health Effects of Water
a. Meeting fluid needs for optimal functioning of body systems
b. Hard water
c. Soft water
d. Bottled water
C. Blood Volume and Blood Pressure – (Figure 12-2) 10e TRA 128; 13e TRA 15
1. ADH – ADH and water retention
a. Antidiuretic hormone (ADH) causes kidneys to reabsorb water
b. Also called vasopressin because this elevates blood pressure
4. Aldosterone
a. Adrenal glands
b. Kidneys retain sodium in order to retain water
D. Fluid and Electrolyte Balance
1. Dissociation of Salt in Water (Figure 12-4) 10e TRA 130
a. Cations and anions
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2. Electrolytes Attract Water (Figure 12-5)
3. Water Follows Electrolytes (Figure 12-6) 11e TRA 25; 10e TRA 131
a. Sodium and chloride
4. Proteins Regulate Flow of Fluids and Ions
5. Regulation of Fluid and Electrolyte Balance
a. Digestive juices of GI tract contain minerals
b. Kidneys maintain fluid balance using ADH
c. Kidneys maintain electrolyte balance using aldosterone
E. Fluid and Electrolyte Imbalance
1. Different Solutes Lost by Different Routes
a. Vomiting or diarrhea
b. Kidneys
c. Uncontrolled diabetics
2. Replacing Lost Fluids and Electrolytes
1. Regulation by the Buffers
2. Regulation in the Lungs – Respiration speeds up and slows down as needed
3. Excretion in the Kidneys
a. Selects which ions to retain and which to excrete
b. The urine’s acidity level fluctuates
II. The Minerals—An Overview (Figure 12-9) IM HN 12-1
A. Inorganic Elements
1. Major minerals or macrominerals
2. Minerals can be lost when they leach into water
B. The Body’s Handling of Minerals
1. Some behave like water-soluble vitamins
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III. The Major Minerals
A. Sodium – Discuss the following:
1. Sodium Roles in the Body
2. Sodium Recommendations
a. Minimum for adults: 500 mg/day
b. Adequate Intakes
1. For those 19-50 years of age, 1,500 mg/day
d. Maximum % Daily Value on food labels is set at 2400 mg/day
3. Sodium and Hypertension IM CS 12-2
a. Impact on high blood pressure
b. Salt sensitivity
c. Dietary Approaches to Stop Hypertension (DASH) diet
B. Chloride – Discuss the following:
1. Chloride Roles in the Body
a. Maintains fluid and electrolyte balance
b. Part of hydrochloric acid
c. Necessary for proper digestion
2. Chloride Recommendations and Intakes
a. Recommendations
1. Adequate Intakes
b. Chloride intakes
1. Abundant in foods
3. Chloride Deficiency and Toxicity
a. Deficiency is rare
C. Potassium – Discuss the following:
1. Potassium Roles in the Body
a. Maintains normal fluid and electrolyte balance
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c. Supports cell integrity
d. Assists in nerve impulse transmission and muscle contractions
e. Maintains the heartbeat
2. Potassium Recommendations and Intakes 10e TRA 133
3. Potassium and Hypertension
4. Potassium Deficiency
5. Potassium Toxicity
a. Supplements or overconsumption of potassium salts
b. Can occur with certain diseases or treatments
c. Muscular weakness and vomiting
d. If given into a vein, potassium can cause the heart to stop
D. Calcium – Discuss the following:
1. Calcium Roles in the Body
a. Hydroxyapatite
2. Calcium in Disease Prevention
a. May protect against hypertension
3. Calcium Balance (Figure 12-12) 10e TRA 134, 135; IM WS 12-3
a. Works with vitamin D
4. Calcium Absorption
1. Stomach acid
2. Vitamin D
3. Lactose
4. Growth hormones
d. Factors that inhibit absorption
1. Lack of stomach acid
5. Calcium Recommendations (Figure 12-13) IM WS 12-4
a. AI for adolescents: 1300 mg/day
6. Calcium Food Sources (Figures 12-14 & 12-15) 10e TRA 136
a. Drink milk
b. Eat yogurt and cheese
7. Calcium Deficiency (Figure 12-16)
a. Osteoporosis
E. Phosphorus – Discuss the following:
1. Phosphorus Roles in the Body
a. Mineralization of bones and teeth
2. Phosphorus Recommendations and Intakes (Figure 12-17)
a. RDA for adults: 700 mg/day for ages 19-70 years
1. Magnesium Roles in the Body
a. Bone mineralization
b. Building of protein
2. Magnesium Intakes (Figure 12-18)
a. RDA for adult men: 400 mg/day for 19-30 years of age
3. Magnesium Deficiency
a. Deficiencies are rare
b. Symptoms
1. Weakness and confusion
b. Low magnesium restricts walls of arteries and capillaries
5. Magnesium Toxicity – Symptoms from nonfood magnesium are diarrhea, alkalosis, and dehydration
G. Sulfate
1. Sulfate requirements are met by consuming a varied diet
2. It is found in essential nutrients including protein
3. There is no recommended intake and there are no known deficiencies (apart from PEM)
IV. Highlight: Osteoporosis and Calcium
A. Bone Development and Disintegration (Figure H12-1) 10e TRA 137, 138; IM CA 12-1
1. Explain and describe cortical bone
2. Explain and describe trabecular bone
B. Age and Bone Calcium 10e TRA 139; IM CA 12-2
1. Maximizing Bone Mass (Figure H12-3)
a. Consume enough calcium and vitamin D to create denser bones
C. Gender and Hormones
1. Men at lower risk than women
2. Hormonal changes
5. Soy offers some protection
D. Genetics
1. Genes may play a role
2. Environment
3. Physical activity, body weight, alcohol, and smoking have a role
E. Physical Activity and Body Weight
1. Muscle strength and bone strength go together
2. Heavy body weights and weight gains place a stress on bones and promote bone density
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H. Other Nutrients IM CA 12-3
1. Adequate protein
2. Adequate vitamin D
3. Vitamin K protects against hip fractures
4. Vitamin C may slow bone loss
Case Studies5
Case Study 12-1: Fluid and Calcium for a Young Athlete
Michael is a 17-year-old high school football player who has recently been doing “two a day” practices in
preparation for the upcoming season. He is in good physical condition at 5 feet 10 inches and 165 pounds. He is
attempting to gain weight, so he has increased his intake of protein foods and estimates he eats approximately 3500
kcalories a day. One particularly hot afternoon, Michael is sweating profusely and begins to feel weak and has a
difficult time keeping up with his usual practice routines. Noticing that his face is visibly flushed, his coach has him
sit out of practice. Michael reports having eaten 2 peanut butter and jelly sandwiches, potato chips, and a can of soda
for lunch about 2 hours before practice. He had a breakfast burrito with eggs and cheese for breakfast with a 12-
ounce glass of orange juice.
1. What signs of dehydration does Michael exhibit?
2. Based on these signs of dehydration, what percentage of body fluid would you estimate Michael has lost?
3. Along with water, what essential nutrients has Michael’s body most likely lost as result of his heavy sweating?
4. Using his reported caloric intake, estimate Michael’s fluid needs.
5. Besides fruit juice and soda, what foods and beverages could help meet Michael’s fluid requirements?
6. What food groups appear to be deficient in Michael’s usual diet? What essential minerals are likely to be
lacking as a result of his limited diet?
7. Using information in the How To feature of this chapter, estimate Michael’s calcium intake. Is this adequate for
his age? If not, what recommendations for increasing his calcium intake would you offer?
Answer Key
1. Flushed skin, impaired physical performance, weakness.
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Case Study 12-2: Recipe Modification for Sodium Control
Elizabeth C. is a 42-year-old African-American woman in reasonably good health. Her mother has high blood
pressure and recently suffered a mild stroke. Elizabeth—who sometimes has her mother over for meals—has
decided to look more closely at the sodium content of the food she prepares for her family.
She is planning to prepare a casserole for her family and looks up the sodium content in milligrams (mg) for the
main ingredients: 2 cups roasted chicken (120 mg per cup), 1 can cream of chicken soup (800 mg sodium per ½ cup
serving; 2.5 servings per can), 1 cup grated cheese (180 mg per ¼ cup), 2 cups frozen broccoli (40 mg per cup), 1
teaspoon salt (480 mg per ¼ teaspoon), and ¼ teaspoon each curry powder (0 mg) and pepper (0 mg).
1. According to the 2010 Dietary Guidelines mentioned in the chapter, what is the recommendation regarding
sodium intake for Elizabeth and her family?
2. Assuming her recipe serves four, calculate the milligrams (mg) of sodium in one serving of Elizabeth’s
casserole.
3. How does this meal contribute to her family’s daily sodium goal addressed in question #1?
4. Using the information in the “How To” feature in this chapter, what general changes might Elizabeth make to
decrease the amount of sodium in this recipe?
5. Assume that Elizabeth has found a lower-sodium soup for her recipe (528 milligrams sodium per serving; 2
servings per can). Using this product and other changes you suggested in question #4, revise her original recipe
and recalculate the sodium content of one serving.
6. Using information from this chapter, what other nutrition strategies might help Elizabeth plan meals for her
family that could help lower blood pressure?
Answer Key
1. Choose foods low in sodium and prepare foods with little salt. African Americans of any age should reduce
daily sodium intake to 1500 milligrams.
Suggested Classroom Activities
This chapter offers students the opportunity to learn many exciting things about the body fluids and major minerals.
The Highlight that follows covers a subject of great interest and controversy (osteoporosis and calcium) and usually
leads to lively class discussion. Several of the vitamin activities presented in Chapter 10 of this manual can also be
used in the study of this chapter. Please see Classroom Activities 10-2 through 10-6.
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Classroom Activity 12-1: Osteoporosis Posture Simulation
Key concept: Effects of osteoporosis Class size: Any
When discussing spinal fractures from osteoporosis and the resulting disfigurement, instruct students to sit up
straight in their chairs. Then have them bend forward and show them by demonstrating this posture. Then tell
students to try to take a deep breath. Ask students to talk about how they feel in this posture and the negative
immediate and long-term health effects, including compression of organs and discomfort leading to pain. You may
have a conversation regarding the negative effect on body image as well.
Classroom Activity 12-2: Using Bags of Flour to Display Bone Losses during Osteoporosis
Key concept: Bone density Class size: Any
Materials needed: 6 sealable plastic bags, 6 labels, 1 bag of all-purpose flour (29 cups)
Instructions: Before class, obtain 6 clear, sealable plastic bags, labels, and a bag of flour. Add flour to each bag in
the following amounts:
This activity is an effective opening for a lecture and/or discussion regarding osteoporosis.
Classroom Activity 12-3: Osteoporosis Prevention (Meal Comparison)6
Key concept: Applying calcium/vitamin D recommendations Class size: Any
Instructions: Present the two breakfast meal plans below to students and use the discussion questions to prompt them
to evaluate the plans.
Breakfast #1
Smoothie made with the following ingredients:
Bran cereal, 1/3 cup
Berries, assorted, frozen, 1 cup
Walnuts, ¼ cup
Skim milk, 1.5 cups
Breakfast #2
McDonalds® Breakfast Value Meal:
Egg McMuffin, 1 item
Hash brown patty, 1 item
Diet Coke, 20 ounces
Discussion questions:
1. What are the EAR for calcium and the RDA for vitamin D for adult men and women? (Hint: Use the chart
inside the front cover of your textbook.)
2. What foods in the meal plans are the major contributors of calcium and vitamin D?
3. How could the calcium and vitamin D content of the meal plans (or any breakfast meal) be improved?
4. What other recommendations do you have for preventing osteoporosis?
Answer key:
1. Calcium: 800 milligrams/day, vitamin D: 15 micrograms/day × (1 microgram cholecalciferol = 40 IU vitamin
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Nutrient composition of meals for instructor reference:
Breakfast #1 Item
Cal
Ca
Vit D
Breakfast #2 Item
Cal
Ca
Vit D
Key: Cal = kcalories, Ca = calcium (milligrams), Vit D = vitamin D (micrograms)
Classroom Activity 12-4: Consumer Brochures on Major Minerals7
Key concept: Nutrition messages on minerals Class size: Small to medium
Instructions: Ask students to select one of the minerals outlined in this chapter and write a three-fold flyer on it that
could be used for patient education.
This exercise allows the student to select a mineral of interest and design a pamphlet for patient education. Limited
words and creative design will be necessary so as to interest the client. The purpose of the assignment is to challenge
the student to limit their word usage in describing an issue or topic. This can be very challenging. Also important is
the language that the student utilizes for the pamphlet, as many individuals do not understand beyond a 7th grade
level of education.
Prepare the students for these factors. This type of assignment is not unusual in the dietetic profession. Help them to
understand the constraints and help them to excel in the language. When the students have completed their
assignments, they should share them with their classmates so that everyone can benefit from the differing
approaches to the project.
How To “Try It” Activities Answer Key
How to Cut Salt (and Sodium) Intake
127 mg Na per ounce for the bagel, 149 mg Na per ounce of potato chips (salted), and 111 mg Na per ounce of
animal crackers (per USDA Nutrient Data Laboratory, http://ndb.nal.usda.gov/ndb/foods/list)
How to Estimate Your Calcium Intake
189 mg Ca per ½ cup almonds, 21 mg Ca per ½ cup broccoli, and 148 mg Ca per ½ cup yogurt (per USDA Nutrient
Data Laboratory)
Study Card 12 Answer Key
1. Water in body fluids: carries nutrients and waste products throughout the body; maintains the structure of large
molecules such as proteins and glycogen; participates in metabolic reactions; serves as the solvent for minerals,
vitamins, amino acids, glucose, and many other small molecules so that they can participate in metabolic
