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Chapter 7
Water and Minerals
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Learning Objectives
 1. State the general characteristics of
minerals
 2. Identify the percentage of body weight
made up of water
 3. List the functions of water in the body
 4. Identify the functions and food sources of
the major minerals and the trace minerals
 5. Identify which minerals are most likely to
be deficient in the American diet
Learning Objectives (cont’d)
 6. Discuss the nutrition of nuts and seeds
and how to use them on the menu
 7. Distinguish between different types of
bottled waters
 8. Explain how dietary supplements are
regulated and labeled
 9. Identify instances when supplements may
be necessary
Minerals
 Major minerals
 Calcium
 Chloride
 Magnesium
 Phosphorus
 Potassium
 Sodium
 Sulfur
 Trace Minerals
 Chromium
 Copper
 Fluoride
 Iodine
 Iron
 Manganese
 Molybdenum
 Selenium
Bioavailability
 Zinc
Toxicity
Cooking
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Functions of Water
 Medium for many metabolic
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activities and also participates in
some metabolic reactions
Carries nutrients to the cells and
carries away waste materials to
the kidneys and out of the body
in urine
Needed in each step of the
process of converting food into
energy and tissue
Maintains blood volume in your
body
Maintain normal body
temperature
Important part of body
lubricants, such as cushioning
joints and internal organs
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How Much Water is Enough?
 AI for total water:
Men: 3.7 liters/day
Women: 2.7 liters/day
 Number of things,
including thirst, work to
keep body water
content within limits
 You lose water through
urine, skin, lungs, GI
tract
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Food Facts: Bottled Waters
 Artesian well water
 Mineral water
 Spring water
 Well water
 Purified water
Bottled water is regulated by the Food and Drug Administration.
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Calcium and Phosphorus
 Used for building bones and teeth
– found in hydroxyapatite
 Calcium –
 Helps blood clot
 Helps muscles contract
 Helps nerves transmit
impulses
 May lower blood pressure
 Phosphorus
 Involved in release of energy
from carb., fat, and protein
 Part of DNA
 Buffers acids and bases
 Activates some enzymes
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Sources of Calcium
Oxalic acid in leafy green vegetables and phytic acic found in whole grains
can decrease absorption of certain nutrients such as calcium and iron
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Calcium: Deficiency and Toxicity
 About 25-30% of calcium you eat is absorbed
 Deficiency
Calcium deficiency is a major contributing
factor in osteoporosis
 Toxicity: UL is 2,500 milligrams
Amounts above UL can contribute to calcium
deposits in kidneys and other organs
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Phosphorus
 Widely distributed in foods
 Rarely lacking in diet
 Excellent sources: milk and milk products,
meat, poultry, fish, eggs, legumes
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Functions of Magnesium
 Many enzyme systems responsible for
energy metabolism and making protein, fat,
and nucleic acids
 Build bones and maintain teeth
 Muscle relaxation, blood clotting, & nerve
transmission
 Keep immune system working properly
 May help regulate blood pressure
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Magnesium is part of chlorophyll, the
green pigment found in plants.
Lettuce
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Sources of Magnesium
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Green leafy vegetables
Potatoes
Nuts (especially almonds and cashews)
Seeds
Legumes
Whole-grain cereals
Seafood
Magnesium occurs in most foods in small
amounts
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Magnesium: Deficiency & Toxicity
 Deficiency is rarely seen, although dietary
surveys suggest that many Americans don’t
get enough
 Symptoms of deficiency: muscle twitching,
cramps, weakness, depression, blood clots
 Very high doses can cause diarrhea and
puts a stress on the kidneys (bad for elderly)
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Electrolytes
 Sodium, potassium, and chlorides are
referred to as electrolytes because when
dissolved in body fluids, they separate into +
or – charged particles called ions
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Sodium + found in fluid outside cells
Chloride – found in fluid outside cells
Potassium + found inside cells
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Functions of Electrolytes
 Water balance
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 Acid-base balance
Inside the cells
Outside the cells
In the blood
vessels
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Fluid Compartments in the Body
Sources of Sodium
 Salt – sodium chloride
 Processed foods:
Canned, cured, and/or smoked
meats and fish such as bacon,
ham
 Many cheeses, esp. processed
cheese
 Canned veggies, etc.
 Frozen convenience foods
 Dried soup mixes - bases
 Foods in brine
 Certain seasonings: salt, soy
sauce, Worcestershire sauce, etc.
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Sodium and Hypertension
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Functions of Potassium
 Helps maintain water balance
 Helps maintain acid-base balance
 Assists in muscle contraction and normal
heartbeat
 Assists in sending nerve impulses
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Sources of Potassium
 Widely distributed in
plant and animal foods
(whole foods)
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Fruits (oranges &
bananas)
Vegetables (potatoes)
Milk and yogurt
Legumes
Meats
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Potassium: Deficiency & Toxicity
 Deficiency is of concern because we don’t
eat many whole foods
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Can also result from dehydration, certain
diseases, or drugs (diuretics)
Symptoms: muscle cramps, weakness,
nausea, abnormal heart rhythms
 Toxicity: can be toxic if too many
supplements taken
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Chloride
 Maintains water balance
 Maintains acid-base balance
 Part of hydrochloric acid in the stomach
 Source: Salt (sodium chloride)
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Sulfur
 Body doesn’t use sulfur by itself, but uses the
nutrients it is found in, such as protein,
thiamin, and biotin
 The protein in hair, skin, and nails is
especially rich in sulfur
 No DRI – protein foods supply plenty of sulfur
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Trace Minerals
 Exciting area of research
 Many trace minerals are toxic at levels only
several times higher than recommendations
 Trace minerals are highly interactive with
each other
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Functions of Iron
 Key component of hemoglobin – a part of red
blood cells that carries oxygen to body’s cells
 Key component of myoglobin – a muscle
protein that stores and carries oxygen that
the muscles use to contract
 Works with many
enzymes in energy
metabolism
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Iron Absorption
 About 15% of dietary iron is absorbed
 More iron is absorbed if:
 Body stores are low
 Body needs to makes lots of RBCs
 Heme iron (predominant
form of iron in animal food)
is absorbed and used twice
as readily as iron in plant foods
(nonheme iron)
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Iron Absorption (cont’d.)
 Increase absorption of
nonheme iron:
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Vitamin C
Meat
Poultry
Fish
 Decrease absorption of
nonheme iron:
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Calcium
Substances found in
tea and coffee
Oxalic acid (in
spinach)
Phytic acid (in grain
fiber)
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Iron: Deficiency & Toxicity
 Iron deficiency – a condition in which iron stores are
used up
 Iron-deficiency anemia – a condition in which the size
and number of RBC are reduced, symptoms include:
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Fatigue, pallor, irritability
Decreased immune function
In kids – slow cognitive and social development
During pregnancy – increased risk of premature
delivery, LBW babies
 Iron overload or hemochromatosis
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Zinc: Cofactor for Almost 100
Enzymes
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Protein, carbohydrate, and fat metabolism
DNA synthesis
Wound healing
Bone formation
Development of sexual organs
Taste perception
 In addition, zinc is needed for general tissue growth
and maintenance, vitamin A activity, protection of cell
membranes from free radicals, storage and release
of insulin
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Sources of Zinc
 Protein foods: shellfish,
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meat, poultry
Legumes
Dairy foods
Whole grains
Fortified cereals
 Absorbed better from
animal sources
 Phytates decrease
absorption
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Zinc: Deficiency & Toxicity
 Deficiency: more likely in pregnant women,
the young and elderly, and vegetarians
 Symptoms in adults: poor appetite, diarrhea,
skin rash, hair loss
 Symptoms in children: growth retardation,
delayed sexual maturation, poor appetite,
decreased taste, delayed wound healing
 Toxicity: long-term intake of zinc over UL
results in copper deficiency
Avoid zinc supplements unless prescribed
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Iodine
 Required for normal thyroid gland functioning
 Thyroid gland makes 2 hormones that
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maintain a normal level of metabolism
are essential to normal growth and
development
are essential to normal body temperature
are essential to protein synthesis
and more
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Sources of Iodine
 Saltwater fish
 Grains grown in iodine-rich soil
 Iodized salt
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Iodine Deficiency
 Hypothyroidism
 Simple goiter
 Cretinism – lack of thyroid secretion causes
mental and physical retardation during
pregnancy and later development
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Functions of Selenium
 Important part of antioxidant enzymes that
protect cells from free radicals
 Needed for normal functioning of thyroid
gland
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Sources of Selenium
 Plant foods, varying on
region
 Meats and seafood
 Bread
 Nuts (Brazil nuts and
walnuts)
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Selenium: Deficiency & Toxicity
 Deficiency: Keshan disease (enlarged heart)
 Deficiency is rare in US
 Toxicity: Moderate to high health risk associated
with too much selenium
 Selenosis: High blood levels of selenium, symptoms
include:
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Gastrointestinal upset
Hair loss
Mild nerve damage
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Fluoride
 Fluoride strengthens
the mineral composition
of developing teeth in
children and also
strengthens bone
 Major source: Drinking
water
 Toxicity: Fluorosis
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Chromium
 Works with insulin to transfer glucose and
other nutrients from the bloodstream into the
body’s cells
 Not known if chromium deficiency is a
concern
 Not known whether chromium supplements
are harmful
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Sources of Chromium
 Widely distributed
throughout foods, but
mostly in small amounts
 Good sources:
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Whole, unprocessed
foods, such as whole
grain breads and
cereals
Wheat germ
Nuts.
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Copper
 Important part of many enzymes. Aids in:
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Forming hemoglobin
Forming collagen
Energy metabolism
 Mostly in unprocessed foods: organ meats,
seafood, nuts, seeds, milk, chicken, potatoes
 Deficiency is rare
 Toxic at 4 times RDA
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Manganese
 Needed to form bone
 Part of an enzyme that acts as an antioxidant
 Needed as a cofactor for many enzymes
involved in CHO, fat, and protein metabolism
 Found in many foods, especially whole
grains, dried fruits, nuts, leafy vegetables
 Too much or too little manganese is rare
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Molybdenum
 Cofactor for several enzymes
 Found in legumes, meat, whole grains, and
nuts
 No major concerns with deficiency or toxicity
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Other Trace Minerals???
 These minerals are essential to animals.
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Arsenic
Boron
Nickel
Silicon
Vanadium
 Based on adverse effects noted in animal
studies, UL have been set for boron, nickel,
and vanadium
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Ingredient Focus: Nuts & Seeds
 Full of vitamins and minerals
 Fiber
 Protein
 A bit of fat – most of the fat (except in
walnuts) is monounsaturated
 Walnuts and flaxseed are rich on alphalinolenic acid (omega-3)
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Food Facts: How Food Processing, Storage,
Preparation, and Cooking Affect Vitamin and Mineral
Content
1. Buy fresh, high-quality food
2. Inspect fresh fruits and veggies for
appropriate color, size, and shape
3. Store fresh fruits and veggies in the
refrigerator (except bananas, avocados,
potatoes, and onions)
4. Minimize storage times and store canned
goods in a cool place
5. Wrap up fresh fruits and veggies in the
refrigerator to decrease exposure to air
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Food Facts: How Food Processing, Storage,
Preparation, and Cooking Affect Vitamin and Mineral
Content (cont’d.)
6. Wash fruits and veggies when ready to use
7. Cut vegetables up no more than necessary
8. Keep skins of fruits as much as possible
9. Steaming, microwaving, and stir-frying are
good choices
10. Frying can destroy vitamins
11. Never use baking soda
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Food Facts: How Food Processing, Storage,
Preparation, and Cooking Affect Vitamin and Mineral
Content (cont’d.)
11. Broiled or roasted meats retain more B
vitamins than meats that are braised or
stewed
12. Use the cooking water from vegetables and
the drippings from meat (after skimming off
the fat) to prepare soup and gravy
13. Prepare foods close to the time of service
14. Don’t keep milk in glass containers
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Dietary Supplements
 Dietary supplements
are not drugs or
replacements for
conventional diets
 Role of FDA
 Types of claims:
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Nutrient claims
Health claims
Nutrition support
claims, which include
“structure-function
claims”
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Copyright ©2010 John Wiley & Sons, Inc.
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