Chapter 9 - Water and the Minerals

Nutrition for Health and Health Care, 5th Edition
DeBruyne ■ Pinna © Cengage Learning 2014
Water and the MineralsChapter 9

Water and Body Fluids
• Water
– Adult: 60 percent of weight
• Function in body fluids
– Carries nutrients and waste products
– Maintains the structure of large molecules
– Serves as the solvent for:
• Minerals, vitamins, amino acids, glucose, and
many other small molecules

Water and Body Fluids (cont’d.)
• Function in body fluids
– Maintains blood volume
– Aids in normal body temperature regulation
– Acts as a lubricant and cushion
• Water balance
– Water intake regulation
• Hypothalamus: initiates drinking

• Water imbalances
– Dehydration
– Water intoxication: hyponatremia
• Water excretion
– Regulated by the brain and kidneys
• What effect does antidiuretic hormone (ADH) have
on the kidneys?
– Average water loss per day: 2 ½ liters

• Adequate Intake (AI) for total water
– Men: 3.7 liters/day
– Women: 2.7 liters/day
• What factors attribute to the varying water
needs per individual?
• Sources
– Water, caffeinated beverages, foods, milk,
juices, etc.

• Body fluids
– Electrolyte solutions
– Regulated closely
• Proteins in the cell membranes: move ions into or
out of the cells
• Kidneys regulate sodium and water
– How does the body’s total electrolytes
compare to the urinary electrolytes?

• Electrolyte mixtures
– Act as buffers
– Kidneys
• Primary role in maintaining acid-base balance

The Major Minerals

The Major Minerals (cont’d.)
• What is the distinction between major
minerals and trace minerals?
• All major minerals (Table 9-7)
– Influence the body’s fluid balance
– Have other specific roles

• Sodium
– Principal electrolyte in the extracellular fluid
– Primary regulator of the extracellular fluid
volume
– What are other roles?
– Sodium AI
• 1500 mg/day (19-50 yr)
– Average U.S. intake: 3400 mg/day

• Sodium
– What does processing do to the sodium and
potassium contents of foods? (Figure 9-2)
– Top contributors of sodium
• Breads, cold cuts, pizza, poultry, soups, etc.
– What is the correlation between sodium intake
and hypertension?
• “How To” Cut Salt Intake; DASH approach

• Chloride
– Major negative ion of the extracellular fluids
– Maintains fluid, electrolyte, and acid-base
balances
– Major source: salt
• Potassium
– Principal positively charged ion inside the
cells

• Potassium
– Maintains fluid and electrolyte balance and
cell integrity
– Distribution inside and outside the cell
• Homeostasis
– Deficiency
• Increase in blood pressure, salt sensitivity, kidney
stones, bone turnover, etc.
• What are the causes of potassium deficiency?

• Potassium
– Toxicity
• Result of overconsumption of salts or
supplements, diseases, or medications
– Best sources
• Fresh fruits and vegetables
– Prevent and correct hypertension
• Ample potassium with low sodium
• DASH approach

• Calcium
– Most abundant mineral in the body
– Integral part of bone structure and serves as a
calcium bank
– Bone formation
• Calcium salts form crystals on a protein collagen
matrix (Figure 9-3)
• Why is it incorrect to think of bones as being inert,
e.g., similar to rocks?

• Calcium
– Ionized calcium in body fluids
• Regulates the transport of ions across cell
membranes, helps maintain normal blood
pressure, is essential for muscle contraction
(including heartbeat), etc.
– High blood calcium levels
• Deposited into bone

• Calcium
– Regulatory system to counter low blood
calcium
1. Small intestine absorbs more calcium.
2. Bones release more calcium into the blood.
3. Kidneys excrete less calcium.
– How is blood calcium affected by a chronic
dietary deficiency of calcium?

• Calcium
– Osteoporosis
• Women: may lose up to 20 percent of bone mass
following menopause
• Why is osteoporosis more prevalent in women
than in men?
• Prevention: adequate calcium and weight-bearing
physical activity

• Calcium
– Disease prevention
• Hypertension, colon and rectal cancers
– Calcium RDA
• Adults (19–50 yr): 1000 mg/day
• Men (51–70): 1000 mg/day
• Women (51–70): 1200 mg/day
• Adults (>70): 1200 mg/day

• Calcium
– Milk and milk products
• Recommended: three cups of milk daily for adults
• “How To” Add Calcium to Daily Meals

• Phosphorus
– Second most abundant mineral in the body
– Found in
• Bones, teeth, and all body tissues
– Part of DNA and RNA
– Best sources
• Animal protein, milk, and cheese

• Magnesium
– Found in bones, muscles, heart, liver, and
other soft tissues; small amount in body fluids
– Functions
• Enzyme functions and other cellular functions;
needed for energy release in cells; required for
normal heart function; etc.
– Deficiency symptoms
• Low blood calcium; muscle cramps and seizures

• Magnesium
– Toxicity
• Rare, but can be fatal
– Present in “hard water”
– Food sources
• Dark green, leafy vegetables; nuts; legumes;
whole-grain breads and cereals; etc.

• Sulfate
– Needed for sulfur-containing compounds
– Helps shape protein strands
• Skin, hair, nails, etc.
– No recommended intake
– No deficiencies known
• A summary of the major minerals
(Table 9-7)

The Trace Minerals
• Iron
– Component in:
• Hemoglobin
• Myoglobin
– Significant iron loss
• Bleeding
– What is the role of the transferrin?
– Hepcidin: central to iron balance

The Trace Minerals (cont’d.)
• Iron deficiency
– Most common nutrient deficiency
– Causes
• Inadequate intake and blood loss
– Assessment
• Low serum ferritin; increased transferrin level
– What is the difference between iron deficiency
and anemia?

• Iron deficiency
– Pica may be present
– Do not self-diagnose
• Hemochromatosis: iron overload
• Iron poisoning

• Iron recommendations
– Men: 8 mg/day
– Women (childbearing years): 18 mg/day
• Iron forms in foods
– Heme iron
– Nonheme iron
– “How To” Add Iron to Daily Meals

• Zinc
– Required by more than 50 enzymes
– Needed
• To perform tasks in eyes, liver, kidneys, muscles,
skin, bones, and male reproductive organs; for
making genetic material; in blood clotting, etc.
– How does the body’s handling of zinc differ
from that of iron?

• Zinc
– Deficiency
• Not widespread in developed countries
– Toxicity
• Produces copper-deficiency anemia
– Zinc RDA
• Men: 11 mg/day
• Women: 8 mg/day

• Selenium
– Functions as an antioxidant nutrient
– Needed for:
• Proper functioning of the iodine-containing thyroid
hormones
– Studies surrounding protection against cancer
– Selenium deficiency
• Keshan disease: heart disease

• Selenium
– High doses: toxic
– RDA
• Adults: 5 µg/day
• Iodine
– Integral part of the thyroid hormones

• Iodine
– Deficiency
• Goiter
• Preventable mental retardation
• Cretinism
– Excess
• Enlarges thyroid gland
– RDA: 150 µg/day

• Copper
– Primary function: constituent of enzymes
• Diverse metabolic roles
– Helps cells use iron
– Deficiency: rare
– Toxicity: may result from some genetic
disorders
– RDA: 900 µg/day

• Manganese
– Cofactor for many enzymes
• Facilitate numerous metabolic processes
– Tolerable Upper Intake Level: 11 mg/day
• Fluoride
– Prevents dental caries
– Deficiency: high dental decay
– Sources: fluoridated water, toothpaste, etc.

• Chromium
– Essential in carbohydrate and lipid
metabolism
– Enhances the activity of insulin
– Best sources
• Liver, brewer’s yeast, whole grains, nuts, and
cheeses

• Molybdenum
– Functions as a working part of several metal-
containing enzymes
• Other trace minerals that contribute to
health
– Nickel, silicon, cobalt, boron, etc.
• A summary of trace minerals (Table 9-8)

Chapter 9 - Water and the Minerals

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