Transcript Toxicity

Chapter 7
Water and Minerals
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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 thru
urine, skin, lungs, GI
tract.
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Calcium and Phosphorus
 Used for building bones and
teeth.
 Calcium –
 Helps blood clot
 Helps muscles contract
 Helps nerves transmit
impulses
 May lower blood pressure
 Phosphorus
 Helps release energy from C,
F, P
 Part of DNA
 Buffers acids and bases
 Makes some enzymes active
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Sources of Calcium
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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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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
 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.
 Helps remove carbon dioxide (waste product)
from the cells so the red blood cells can carry
it to the lungs for disposal (exhaling).
 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
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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
Used to make amino acids and certain hormones and
neurotransmitters
Part of enzymes found in leukocytes (immune
system)
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Iron Absorption
 About 15% of dietary iron is absorbed.
 More iron is absorbed if:
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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
 Wound healing
 Taste perception
 Bone formation
 Vitamin A activity
 DNA synthesis
 Protection of cell
 Protein, carbohydrate,
membranes from freeradical attacks
 Storage and release of
insulin
and fat metabolism
 Development of sexual
organs
 General tissue growth
and maintenance
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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
 Hypothtroidism
 Simple goiter
 Cretinism – lack of thyroid secretion causes
mental and physical retardation during fetal
and later development
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Functions of Selenium
 Important part of antioxidant enzymes that
protect cells from free radicals.
 Also essential for the normal functioning of
the immune system.
 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.
Normal functioning of nervous system,
immune system, and energy release.
 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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Osteoporosis
 A disease characterized by:
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Low bone mass
Structural deterioration of bone tissue
Fragile bones
Increased susceptibility to fractures of hip,
spine, and wrist
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Osteoporosis
 Peak bone mass is
attained during the early
thirties. Bone is being
constantly remodeled,
and after the early
thirties bone is broken
down faster than it is
deposited (especially
during the five years
after menopause for
women due to estrogen
decrease).
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Risk Factors for Osteoporosis
 You can’t change these:
 Gender
 Age
 Body size
 Ethnicity
 Family history
 You can change these:
 A diet low in calcium
and vitamin D
 Sedentary lifestyle
 Cigarette smoking
 Excessive use of
alcohol
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Prevention of Osteoporosis
 The best approach to
osteoporosis is prevention –
 taking in the AI for
calcium
 regular exercise
 consuming milk for
adequate vitamin D
 consuming moderate
amounts of alcohol
 avoiding smoking.
 Medications, such as
Fosamax, can increase bone
density.
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Treatment of Osteoporosis
 Proper nutrition – calcium and vitamin D
 Exercise
 Safety practices to prevent falls
 Possibly medications
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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: Bottled Waters
 Artesian well water
 Mineral water
 Spring water
 Well water
 Purified water
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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 ©2007 John Wiley & Sons, Inc.
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