1 chapter 7 water and minerals. 2 minerals major minerals calcium chloride magnesium phosphorus...
TRANSCRIPT
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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 Zinc
Bioavailability
Toxicity
Cooking
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Functions of Water Medium for many metabolic
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
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 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 Inside the cells Outside the cells In the blood
vessels
Acid-base balance
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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) 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. 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 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:
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: Vitamin C Meat Poultry Fish
Decrease absorption of nonheme iron 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: 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 Bone formation DNA synthesis Protein, carbohydrate,
and fat metabolism Development of sexual
organs General tissue growth
and maintenance
Taste perception Vitamin A activity Protection of cell
membranes from free-radical attacks
Storage and release of insulin
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Sources of Zinc
Protein foods: shellfish, 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
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: 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: 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: 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. 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: 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 alpha-
linolenic 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:
Nutrient claims Health claims Nutrition support
claims, which include “structure-function claims”
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Copyright ©2007 John Wiley & Sons, Inc.