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7. Major minerals are those essential mineral nutrients that the human body requires in relatively large amounts
(greater than 100 milligrams per day), whereas trace minerals are those that the human body requires in
8. Unlike the organic vitamins, which are easily destroyed, minerals are inorganic elements that always retain their
chemical identity. The minerals also differ from the vitamins in the amounts the body can absorb and in the
9. b
10. Sodium is the principal cation of the extracellular fluid and the primary regulator of its volume. Sodium also
helps maintain acid-base balance and is essential to nerve impulse transmission and muscle contraction. After it
11. Calcium it is an integral part of bone structure, providing a rigid frame that holds the body upright and serves as
attachment points for muscles, making motion possible. Bone calcium also serves as a calcium bank, offering a
readily available source of calcium to the body fluids should a drop in blood calcium occur. Many of calcium’s
actions in extracellular fluid help to maintain normal blood pressure, perhaps by stabilizing the smooth muscle
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12. Calcium sources include milk and milk products, some brands of tofu, corn tortillas, some nuts (such as
almonds), some seeds (such as sesame seeds), oysters, small fish eaten with bones, mustard and turnip greens,
13. About 85 percent of body phosphorus is found combined with calcium in the hydroxyapatite crystals of bones
and teeth. Phosphorus is found in all body cells as part of a major buffer system, and as part of DNA and RNA
(making it necessary for all growth). The high-energy compound ATP uses three phosphate groups to do its
Critical Thinking Questions8
1. Explain how the concept of obligatory water excretion helps to explain how fluid balance is regulated in the
individual. What factors may lead to alterations in the obligatory water excretion process in the body?
2. Explain how the kidneys help to maintain fluid balance.
3. Explain the cellular response to alterations in sodium levels in the body. What are the potential advantages
and/or disadvantages to these sodium alterations?
4. How does acid–base balance affect the body’s ability to maintain metabolic function, and how is an imbalance
corrected?
5. What factors affect the bioavailability of a mineral? Why is this significant in terms of functionality of minerals
in the body?
6. How does following the DASH diet affect consumption of minerals?
Answer Key
1. Obligatory water excretion refers to the inherent ability of the body to excrete water in order to get rid of waste
products. This is vital to the well-being of the individual, for it allows elimination of waste products so they do
not accumulate in the body. Once this need for obligatory water excretion is met, then the body will adjust fluid
2. The kidneys play an important role in maintenance of fluid balance by varying the amounts of water and
electrolytes excreted in urine and by releasing the enzyme renin. Renal function is maintained by sufficient
blood perfusion. In response to changes in blood volume and/or blood pressure, hormones help to adjust renal
3. Sodium levels affect cells due to the ability of sodium to affect osmotic changes. High sodium levels are
associated with cellular dehydration and shrinking. Low sodium levels are associated with cellular edema.
4. If the body encounters an alteration in acid-base balance, this can affect metabolic function, for it shifts resting
metabolism from primarily aerobic to anaerobic pathways. The initial response to acid-base alterations is
5. The absorption of minerals in the body is affected by a variety of factors, most notably by binders that affect
chemical release of the mineral. Binders such as phytates and oxalates prevent absorption of minerals. Binding
of minerals in the gastrointestinal tract can also lead to impaired absorption. Additionally, minerals are affected
6. Dietary Approaches to Stop Hypertension are based on a diet that is rich in vegetables, fruits, and whole grains,
providing potassium, magnesium, fiber, and lean protein. The minerals potassium and magnesium help to
reduce blood pressure. Moderation of sodium intake is also associated with decreased blood pressure.
IM Worksheet Answer Key
Worksheet 12-1: Facts about Water (Internet Exercise)
Worksheet 12-2: Water Recommendations
1. 18-year-old male → 14 cups or 3.3 L; not meeting
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Worksheet 12-3: How to Interpret Calcium Serum Levels
1. 8.5 to 10.5 mg/dL
Worksheet 12-4: Iron and Calcium in Your Diet – Answers will vary.
Worksheet 12-5: Chapter 12 Crossword Puzzle
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Worksheet 12-1: Facts about Water (Internet Exercise)
1. Water constitutes approximately 60% of body weight.
a. True
b. False
2. Which one of the following statements is true?
3. There is little scientific evidence to support the familiar advice to drink 8 glasses of water a day.
4. Infants, elderly adults, and athletes are all at risk for developing dehydration.
a. True
b. False
5. Experts advise that more of a healthy adult’s fluid needs should be met by milk or soy milk beverages
6. Which of the following statements is true concerning water requirements?
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Worksheet 12-2: Water Recommendations
Please indicate whether or not each individual listed below is meeting, not meeting, or exceeding his or her
recommended daily fluid intake. (Assume they are not obtaining a significant amount of water from foods.)
• An easy way to determine water needs is to take your weight and divide it in half, then divide that number by 8
to arrive at cups per day.
• Also, activity levels influence the amount of fluids that you will need on a daily basis.
2. An 18-year-old female who drinks 10 cups of fluids during the day.
4. An adult female who drinks 1 liter of fluids during the day.
6. An athlete who drinks 20 cups of fluids, who expends 3000 kcalories per day.
8. A 9-month-old infant who drinks 2 cups of fluids during the day.
9. A person who weighs 120 pounds and drinks 8 cups of fluid during the day.
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Worksheet 12-3: How to Interpret Calcium Serum Levels
General Research:
1. What is the total serum calcium level in the body for a healthy adult?
2. What types of calcium make up the total calcium level?
6. What body organs should be evaluated for their impact on serum calcium levels?
Individual Research:
7. Determine how much calcium you take in over a 2–day time period.
8. Have you met your daily requirements? Why or why not?
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Worksheet 12-4: Iron and Calcium in Your Diet
The two minerals most likely to fall short in the diet are iron and calcium. Interestingly, both are found in protein–
rich foods, but not in the same foods. Meats, fish, and poultry are rich in iron but poor in calcium. Conversely, milk
and milk products are rich in calcium but poor in iron. Including meat or meat alternates for iron and milk and milk
products for calcium can help defend against iron deficiency and osteoporosis, respectively. Determine whether
these food choices are typical of your diet.
1. Do you eat a variety of foods, including some meats, seafood, poultry, or legumes, daily?
Meats, fish, poultry, or eggs
Milk or milk products
Nuts (such as almonds) or seeds (such as sesame seeds)
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Worksheet 12-5: Chapter 12 Crossword Puzzle
1
2
3
4
5
6
7
8
9
10
11
12
Across:
3. Essential for developing and maintaining bone
health
5. Key component of ATP
10. _____ beverages also contribute to meeting daily
fluid requirements.
12. Essential for nerve impulse transmission and muscle
contraction because of its role as the primary
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Handout 12-1: RDA/AI and UL for Major Minerals Compared