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Chapter 9Chapter 9

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Water and MineralsWater and Minerals

CChapter 9hapter 9 Insert photo from 1st page of chapter

Chapter Learning OutcomesChapter Learning Outcomes

1.1. Discuss the functions of water in the body as Discuss the functions of water in the body as well as typical sources of intakes and losses.well as typical sources of intakes and losses.

2.2. Discuss how the body maintains its water Discuss how the body maintains its water balance.balance.

3.3. List major signs and symptoms of heat-related List major signs and symptoms of heat-related illnesses.illnesses.

4.4. Classify mineral nutrients as major, trace, or Classify mineral nutrients as major, trace, or ultratrace minerals.ultratrace minerals.

5.5. Describe factors that can affect the absorption, Describe factors that can affect the absorption, retention, and availability of mineral nutrients.retention, and availability of mineral nutrients.

Chapter Learning Outcomes Chapter Learning Outcomes (continued) (continued)

6.6. List key functions and major food sources of List key functions and major food sources of mineral nutrients.mineral nutrients.

7.7. Identify signs and symptoms associated with Identify signs and symptoms associated with deficiencies as well as excesses of mineral deficiencies as well as excesses of mineral nutrients.nutrients.

8.8. Describe roles of minerals in achieving and Describe roles of minerals in achieving and maintaining good health.maintaining good health.

9.9. Identify major risk factors for hypertension and Identify major risk factors for hypertension and osteoporosis.osteoporosis.

Quiz YourselfQuiz Yourself True or FalseTrue or False

1.1. Your body constantly loses water through Your body constantly loses water through insensible perspiration, a form of water loss that insensible perspiration, a form of water loss that is not the same as sweat. T Fis not the same as sweat. T F

2.2. Ounce per ounce, cottage cheese contains Ounce per ounce, cottage cheese contains more calcium than plain yogurt. T Fmore calcium than plain yogurt. T F

3.3. Potassium, sodium, and chloride ions are Potassium, sodium, and chloride ions are involved in fluid balance. T Finvolved in fluid balance. T F

4.4. Arsenic is an ultratrace mineral. T FArsenic is an ultratrace mineral. T F5.5. In general, plants are good dietary sources of In general, plants are good dietary sources of

iron because the plant pigment chlorophyll iron because the plant pigment chlorophyll contains iron. T Fcontains iron. T F

Quiz Yourself Quiz Yourself True or FalseTrue or False

1.1. TrueTrue Your body constantly loses water through Your body constantly loses water through insensible perspiration, a form of water loss that insensible perspiration, a form of water loss that is not the same as sweat.is not the same as sweat.

2.2. FalseFalse Ounce per ounce, cottage cheese Ounce per ounce, cottage cheese contains contains lessless calcium than plain yogurt. calcium than plain yogurt.

3.3. TrueTrue Potassium, sodium, and chloride ions are Potassium, sodium, and chloride ions are among the ions involved in fluid balance.among the ions involved in fluid balance.

4.4. TrueTrue Arsenic is an ultratrace mineral. Arsenic is an ultratrace mineral.5.5. FalseFalse In general, plants are In general, plants are notnot good dietary good dietary

sources of iron. The plant pigment chlorophyll sources of iron. The plant pigment chlorophyll contains magnesium contains magnesium notnot iron. iron.

WaterWater

Water (HWater (H22O)O)

– Comprised of 2 hydrogen atoms and 1 oxygen Comprised of 2 hydrogen atoms and 1 oxygen atomatom

– Needs no digestion and is easily absorbedNeeds no digestion and is easily absorbed

– Makes up 45 to 75% of body weightMakes up 45 to 75% of body weight Elderly ~45% Infants ~75%Elderly ~45% Infants ~75%

– Major solventMajor solvent

– Very essential—without water, death occurs Very essential—without water, death occurs within 1 to 2 weeks.within 1 to 2 weeks.

Body Temperature RegulationBody Temperature Regulation

Metabolism generates body heatMetabolism generates body heat

– If body temperature reaches If body temperature reaches 1061060 0 FF, excess , excess heat denatures enzymes and damages body heat denatures enzymes and damages body tissues which may result in death.tissues which may result in death.

– Evaporation of water in perspiration Evaporation of water in perspiration releases releases heat to maintain normal body temperature.heat to maintain normal body temperature.

Each Each literliter of perspiration that evaporates of perspiration that evaporates represents loss of ~500 kcal of energy.represents loss of ~500 kcal of energy.

Body Water Compartments Body Water Compartments

Intracellular waterIntracellular water (fluid): (fluid): water inside cellswater inside cells

Extracellular waterExtracellular water (fluid): (fluid): water surrounding cells water surrounding cells or in blood vesselsor in blood vessels ( (plasmaplasma))

Plasma membranePlasma membrane of human cell is of human cell is selectively selectively permeablepermeable

Osmosis Osmosis — the diffusion (movement) of water — the diffusion (movement) of water through a selectively permeable membranethrough a selectively permeable membrane

ConcentrationConcentration of substances dissolved in water of substances dissolved in water influences osmosis influences osmosis

Body Water DistributionBody Water Distribution

Simple diffusionSimple diffusion – molecular movement– molecular movementfrom a region of higher to lower concentrationfrom a region of higher to lower concentration

Insert figure 9.1

Body Water DistributionBody Water Distribution

Osmosis Osmosis – movement of water through a– movement of water through a

selectively permeable membraneselectively permeable membrane

Insert Figure 9.2

Two Major Water CompartmentsTwo Major Water Compartments

Intracellular WaterIntracellular WaterWater inside the cellsWater inside the cells~ 2/3 of body water is intracellular~ 2/3 of body water is intracellular

Extracellular WaterExtracellular WaterWater surrounding the cells or in the fluid portion of Water surrounding the cells or in the fluid portion of blood blood (plasma)(plasma)

Balance between intra- and extracellular fluid isBalance between intra- and extracellular fluid ismaintained by concentration of maintained by concentration of ionsions..

Main ions = sodium, potassium, chloride, and Main ions = sodium, potassium, chloride, and phosphate phosphate

Fluid Compartments in the BodyFluid Compartments in the Body

• Insert Figure 9.3Insert Figure 9.3

Maintaining Proper HydrationMaintaining Proper Hydration

HydrationHydration refers to adequate water statusrefers to adequate water status

shifts in ion concentration can affect hydration. shifts in ion concentration can affect hydration.

Insert figure 9.1

Sources of WaterSources of Water

Total Water IntakeTotal Water Intake – Includes water in beverages and foodsIncludes water in beverages and foods

• Water weight of fruits and vegetables typically Water weight of fruits and vegetables typically ranges from 60 to 95%.ranges from 60 to 95%.

Metabolic Water Metabolic Water – Water formed by cells as a metabolic by-Water formed by cells as a metabolic by-

productproduct

How Much Water is in That How Much Water is in That Food or Beverage?Food or Beverage?

• Insert Table 9.1Insert Table 9.1

The Essential Balancing ActThe Essential Balancing Act

Body water is lost through:Body water is lost through:– urine, perspiration, exhaled air, feces, and urine, perspiration, exhaled air, feces, and

insensible perspiration.insensible perspiration.

Insensible perspirationInsensible perspiration:: body water that passesbody water that passesthrough the skin and is not from sweat glands.through the skin and is not from sweat glands.

Typical fluid intake = fluid lost Typical fluid intake = fluid lost Average is ~2.5 qt/dAverage is ~2.5 qt/d

Daily Water BalanceDaily Water Balance

• Insert figure 9.5

Kidneys and HydrationKidneys and Hydration

Kidneys:Kidneys: – Are the major regulator of body’s water Are the major regulator of body’s water

content and ion concentration.content and ion concentration.– Maintain proper hydration by filtering excess Maintain proper hydration by filtering excess

ions from the blood.ions from the blood.• Remove excess sodium ions; water Remove excess sodium ions; water

follows sodium.follows sodium.– Remove drugs and metabolic wastes. Remove drugs and metabolic wastes.

• UreaUrea and and uric acid uric acid — waste products of — waste products of protein metabolism.protein metabolism.

Water ConservationWater Conservation

• Water conservation occurs when a person is Water conservation occurs when a person is hot and perspires heavily.hot and perspires heavily.

• Hormones that participate in sodium and waterHormones that participate in sodium and water

conservation include:conservation include:

-Antidiuretic hormone (ADH)-Antidiuretic hormone (ADH)

-Aldosterone-Aldosterone

Effects of Antidiuretic Hormone and Effects of Antidiuretic Hormone and Aldosterone on KidneysAldosterone on Kidneys

• Insert Table 9.7Insert Table 9.7

How Much Water Is Needed?How Much Water Is Needed?

Adequate IntakeAdequate Intake ( (AIAI) for ) for totaltotal water water(including water in foods) is:(including water in foods) is:

Young WomenYoung Women = 11 cups (2.7 L)/day = 11 cups (2.7 L)/day Young MenYoung Men = 15.5 cups (3.7 L)/day = 15.5 cups (3.7 L)/day

Urine output is best indicator of adequate water Urine output is best indicator of adequate water intake. intake.

What Is a Diuretic?What Is a Diuretic?

Diuretics — substances that increase urine Diuretics — substances that increase urine output.output.

Two common diuretics:Two common diuretics:Caffeine Caffeine – In coffee, tea, “energy” drinks, and – In coffee, tea, “energy” drinks, and soft drinkssoft drinks

Alcohol Alcohol – In beer, wine, and spiritis– In beer, wine, and spiritisInhibits ADH resulting in urinary water losses > amount of fluid Inhibits ADH resulting in urinary water losses > amount of fluid

consumedconsumed

““Hangovers”Hangovers” may be an effect of may be an effect of dehydration on the brain.dehydration on the brain.

DehydrationDehydration

When the body’s fluid loses are greater When the body’s fluid loses are greater than its input, than its input, dehydrationdehydration occurs. occurs.

• Weight loss is a sign of dehydration.Weight loss is a sign of dehydration.

Every 16 oz of water lost by Every 16 oz of water lost by

the body represents 1 lb of the body represents 1 lb of

body weight.body weight.

Dehydration

Body fluid loss Symptom/condition

1 to 2% Fatigue and thirst

4% Loss of muscular strength and endurance

7 to10% Severe weakness

20% Death

People at Risk for DehydrationPeople at Risk for Dehydration

• Older adults Older adults – do not sense thirst as – do not sense thirst as quickly as younger people.quickly as younger people.

• Sick people Sick people –– especially sick children especially sick children with fever, vomiting, and diarrhea.with fever, vomiting, and diarrhea.

• Athletes Athletes and and peoplepeople who work or who work or exercise outdoorsexercise outdoors in hot weatherhot weather.

Can Too Much Water Be Can Too Much Water Be Toxic?Toxic?

Water intoxicationWater intoxication –– t too much water oo much water consumed at a time or conditions in which consumed at a time or conditions in which kidneys have difficulty filtering water from kidneys have difficulty filtering water from blood blood

• Excess water dilutes sodium concentration of Excess water dilutes sodium concentration of blood, disrupting water balanceblood, disrupting water balance

– Signs and symptoms: Signs and symptoms: • Dizziness, headache, confusion, poor coordination, Dizziness, headache, confusion, poor coordination,

bizarre behavior, and seizuresbizarre behavior, and seizures

Minerals: Basic ConceptsMinerals: Basic Concepts

What are minerals?What are minerals?• Elements in Earth’s rocks, soil, and Elements in Earth’s rocks, soil, and

natural water sources.natural water sources.

• About 15 mineral elements are About 15 mineral elements are essential nutrients.essential nutrients.

• Classified as Classified as micronutrientsmicronutrients because because they are required in mg or mcg amounts.they are required in mg or mcg amounts.

Classifying Mineral NutrientsClassifying Mineral Nutrients

• Main categories of minerals Main categories of minerals – MajorMajor

• Required in amounts >100 mg/dRequired in amounts >100 mg/d– TraceTrace

• Required in amounts <100 mg/dRequired in amounts <100 mg/d– UltratraceUltratrace

• Body contains very small amountsBody contains very small amounts

Minerals with Known or Minerals with Known or Possible Roles in the BodyPossible Roles in the Body

• Insert Table 9.2

Summary of Major MineralsSummary of Major Minerals

• Insert Table 9.3

Why Are Minerals Necessary?Why Are Minerals Necessary?

Diverse roles, includingDiverse roles, including::– Structural components of tissuesStructural components of tissues– IonsIons– Blood clottingBlood clotting– Fluid balanceFluid balance– Acid-base balanceAcid-base balance– Cofactors in chemical reactionsCofactors in chemical reactions– Part of certain enzymes and hormonesPart of certain enzymes and hormones– Aid in energy release from macronutrientsAid in energy release from macronutrients

Minerals and Their Functions Minerals and Their Functions

• Insert Table 9.8

Sources of Minerals Sources of Minerals

Most foods contain mineralsMost foods contain minerals– Animal foods generally contain higher Animal foods generally contain higher

amounts of minerals than plant foods.amounts of minerals than plant foods.– Processing often reduces mineral contents of Processing often reduces mineral contents of

foods.foods.

BioavailabilityBioavailability of minerals varies of minerals varies– In general, minerals in animal foods are more In general, minerals in animal foods are more

easily absorbed than minerals in plant foods.easily absorbed than minerals in plant foods.

Other Sources of Minerals Other Sources of Minerals

Tap waterTap water• ““Hard” water contains a variety of minerals, Hard” water contains a variety of minerals,

including calcium, sulfur, copper, iron, and zinc.including calcium, sulfur, copper, iron, and zinc.• Most public water supplies provide optimal Most public water supplies provide optimal

fluoride levels, because the mineral has been fluoride levels, because the mineral has been added to the water.added to the water.

Dietary supplementsDietary supplements– A daily multiple vitamin and mineral supplement is A daily multiple vitamin and mineral supplement is

generally safe for healthy people. generally safe for healthy people. – Supplements of single minerals may be toxic, if taken Supplements of single minerals may be toxic, if taken

in excess.in excess.

Mineral IntakesMineral Intakes

Many minerals haveMany minerals have

a a narrow rangenarrow range of safe of safe

intake. As a result, it isintake. As a result, it is

relatively easy to relatively easy to

consume a toxicconsume a toxic

amount, especially byamount, especially by

taking supplementstaking supplements

that only contain athat only contain a

particular mineral.particular mineral.

• Insert Figure 9.9

Major Minerals: CalciumMajor Minerals: Calcium

• The most plentiful mineral in human bodyThe most plentiful mineral in human body– > 99% is in bones and teeth> 99% is in bones and teeth– ~ 1% is in extracellular fluid~ 1% is in extracellular fluid

• Healthy adults absorb ~25% of calcium.Healthy adults absorb ~25% of calcium.– Absorption Absorption increasesincreases during growth. during growth.– Absorption Absorption decreasesdecreases with advanced age, with advanced age,

vitamin D deficiency, diarrhea, and high vitamin D deficiency, diarrhea, and high intakes of phosphorus, oxalic acid, and intakes of phosphorus, oxalic acid, and phytic acid.phytic acid.

Why Is Calcium Necessary?Why Is Calcium Necessary?

Functions of calcium include:Functions of calcium include:

• Bone formation and maintenanceBone formation and maintenance• Structural component of teethStructural component of teeth• Muscle contractionMuscle contraction• Blood clot formationBlood clot formation• Nerve impulse transmissionNerve impulse transmission• Cell metabolismCell metabolism

May help control blood pressure and immune May help control blood pressure and immune functioningfunctioning

Bone Development and MaintenanceBone Development and Maintenance

Bones are constantly remodeled in Bones are constantly remodeled in response to physical stress.response to physical stress.• Remodeling involves two types of cells:Remodeling involves two types of cells:

OsteoclastsOsteoclasts — tear down bone tissue where — tear down bone tissue where it is not neededit is not needed

OsteoblastsOsteoblasts — add bone to where it is — add bone to where it is neededneeded

Thyroid and Parathyroid Glands Thyroid and Parathyroid Glands

• Insert Figure 9.11

Thyroid gland: Thyroid gland: Secretes Secretes calcitonincalcitonin when blood calcium is too high when blood calcium is too high

• StimulatesStimulates osteoblastsosteoblasts

Parathyroid glands:Parathyroid glands:Secrete Secrete parathyroid hormone (PTH)parathyroid hormone (PTH) when blood when blood calcium is too lowcalcium is too low

• StimulatesStimulates osteoclastsosteoclasts

Role of Thyroid and Parathyroid Glands

Calcium Content of Selected FoodsCalcium Content of Selected Foods

• Insert Table 9.4

Good Food Sources of Calcium Good Food Sources of Calcium

• Insert figure 9.13

What is Osteoporosis?What is Osteoporosis?

• A chronic disease characterized A chronic disease characterized by by low bone masslow bone mass and and reduced reduced bone structurebone structure leading to leading to increased risk of bone fracturesincreased risk of bone fractures– Among people over age 50, Among people over age 50,

~10 million have osteoporosis and ~10 million have osteoporosis and

34 million are at risk.34 million are at risk.– An estimated 1.5 million Americans An estimated 1.5 million Americans

have an osteoporosis-related have an osteoporosis-related fracture each year.fracture each year.

Insert figure 9.14

Risk Factors for OsteoporosisRisk Factors for Osteoporosis

Insert Table 9.5

Calcium ToxicityCalcium Toxicity

Upper Level (UL) is 2500 mg/dUpper Level (UL) is 2500 mg/d– Excess calcium can result inExcess calcium can result in

hypercalcemiahypercalcemia– Signs/symptoms:Signs/symptoms:

» Kidney stones, bone pain, muscle Kidney stones, bone pain, muscle weakness, fatigue, and weakness, fatigue, and hypertensionhypertension

Sodium (Na)Sodium (Na)

• Table saltTable salt = sodium + chloride = sodium + chloride– 1 tsp salt supplies 2325 mg sodium1 tsp salt supplies 2325 mg sodium

• Why is Why is SodiumSodium Necessary? Necessary?– Major positively charged ion in Major positively charged ion in

extracellular fluidextracellular fluid– Conducts nerve impulsesConducts nerve impulses– Involved in transporting glucose and Involved in transporting glucose and

amino acids into cellsamino acids into cells

Sodium Content of Selected Sodium Content of Selected Foods/Food AdditiveFoods/Food Additive

Insert Table 9.7

Dietary Adequacy for SodiumDietary Adequacy for Sodium

• Only ~ 180 mg sodium Only ~ 180 mg sodium requiredrequired per dayper day– AI = 1500 mg/dAI = 1500 mg/d

• Those who perspire heavily lose Those who perspire heavily lose sodium in sweat and need moresodium in sweat and need more

Sodium Deficiency and ToxicitySodium Deficiency and Toxicity

• DeficiencyDeficiency– May occur when > 2 to 3% of body weight May occur when > 2 to 3% of body weight

is lost through sweatingis lost through sweating

• ToxicityToxicity– UL = 2300 mg/dUL = 2300 mg/d

• Average American consumes >2500 Average American consumes >2500 mg/dmg/d

– High sodium intakes associated with High sodium intakes associated with increased risk of hypertensionincreased risk of hypertension

Sodium and Hypertension Sodium and Hypertension

• HypertensionHypertension — condition — condition characterized by persistently elevated characterized by persistently elevated blood pressureblood pressure– Estimated 27% of American adults have Estimated 27% of American adults have

the conditionthe condition– Hypertension increases risk of: Hypertension increases risk of:

• Heart diseaseHeart disease• StrokeStroke• Kidney failureKidney failure

Blood PressureBlood Pressure

• Systolic pressure Systolic pressure — maximum blood — maximum blood pressure within arteries when ventricles pressure within arteries when ventricles of the heart contractof the heart contract

• Diastolic pressure Diastolic pressure — pressure when — pressure when ventricles relax between contractionsventricles relax between contractions

Systolic value is always higher than Systolic value is always higher than diastolic valuediastolic value

Categories of Blood Pressure Categories of Blood Pressure Levels in Adults Levels in Adults

• Insert table 9.18

Insert Table 9.9

Many risk factors for hypertension can be controlled

by following a healthy lifestyle.

• Insert Table 9.10Practical Steps to Reduce Risk of Hypertension

Potassium (K)Potassium (K)

Why is Why is PotassiumPotassium Necessary? Necessary? • Major positively charged ion in intracellular Major positively charged ion in intracellular

fluidfluid– Needed for nerve impulses, contracting muscles, Needed for nerve impulses, contracting muscles,

and kidney functionand kidney function– Potassium-rich diets may reduce blood pressurePotassium-rich diets may reduce blood pressure

Dietary AdequacyDietary Adequacy– AI = 4700 mg/dAI = 4700 mg/d

• Most Americans consume ~2700 mg/d Most Americans consume ~2700 mg/d

Good Food Sources of PotassiumGood Food Sources of Potassium

Insert Figure 9.15

Potassium Content of Selected FoodsPotassium Content of Selected Foods

Insert Table 9.11

Magnesium (Mg)Magnesium (Mg)

• Participates in >300 chemical reactionsParticipates in >300 chemical reactions

• Roles the body include:Roles the body include:– Regulation of muscle and nerve functionRegulation of muscle and nerve function– Maintenance of strong bones Maintenance of strong bones – Strengthening the immune systemStrengthening the immune system

• Dietary AdequacyDietary Adequacy– Adult RDA = 310 to 420 mg/dAdult RDA = 310 to 420 mg/d

Magnesium Content of Selected FoodsMagnesium Content of Selected Foods

Insert Table 9.12

Good Food Sources of MagnesiumGood Food Sources of Magnesium

Insert Figure 9.16

Magnesium Deficiency and Magnesium Deficiency and Toxicity Toxicity

• DeficiencyDeficiency• Rare among healthy AmericansRare among healthy Americans• Most likely in girls between 14-18 yrs of Most likely in girls between 14-18 yrs of

ageage

• ToxicityToxicity• Results from ingesting excessive Results from ingesting excessive

laxatives, antacids, or dietary laxatives, antacids, or dietary supplementssupplements

Summary of Trace MineralsSummary of Trace Minerals

• Insert Table 9.13

Iron (Fe)Iron (Fe)

Why is Why is IronIron Necessary? Necessary?• Iron is a component of Iron is a component of hemoglobinhemoglobin and and

myoglobin.myoglobin.• Hemoglobin Hemoglobin — iron containing protein in RBC — iron containing protein in RBC

that transports oxygen to tissues and some that transports oxygen to tissues and some COCO22 away from tissues away from tissues

• Myoglobin Myoglobin — iron-containing protein in muscle — iron-containing protein in muscle cells that controls oxygen uptake from RBCcells that controls oxygen uptake from RBC

• Iron is involved in energy generation and Iron is involved in energy generation and immune function.immune function.

Iron Content of Selected FoodsIron Content of Selected Foods

Insert Table 9.14

Good Food Sources of IronGood Food Sources of Iron

Insert Figure 9.17

Iron: Dietary Adequacy Iron: Dietary Adequacy

• RDARDA• Women = 18 mg/d Women = 18 mg/d

• Most females from ages 14 to 50 Most females from ages 14 to 50 yrs have low intakes.yrs have low intakes.

• Men = 8 mg/dMen = 8 mg/d

• Most males >age 9 yrs have Most males >age 9 yrs have adequate intakes.adequate intakes.

Iron Deficiency-Related DisordersIron Deficiency-Related Disorders

Anemia Anemia impairs oxygen transport in blood.impairs oxygen transport in blood.

Insert figure 9.18

Normal RBC Hypochromic, microcytic RBC

Signs and Symptoms of Iron Signs and Symptoms of Iron Deficiency AnemiaDeficiency Anemia

Insert Table 9.15

Iron Toxicity Iron Toxicity

• Upper Limit (UL) = 45 mg/dUpper Limit (UL) = 45 mg/d• May occur in children <6 yrs due to May occur in children <6 yrs due to

supplement overdosesupplement overdose• Signs include vomiting and diarrhea, Signs include vomiting and diarrhea,

progressing to coma and deathprogressing to coma and death

• Hereditary HemochromatosisHereditary Hemochromatosis• Common hereditary disorder resulting in Common hereditary disorder resulting in

excess iron absorptionexcess iron absorption

Zinc (Zn)Zinc (Zn)

Why is Why is ZincZinc Necessary? Necessary?

• It’s a component of hundreds of It’s a component of hundreds of enzymes and other proteins.enzymes and other proteins.

• It is needed for:It is needed for:• Wound healingWound healing• Normal of taste and smellNormal of taste and smell• DNA synthesisDNA synthesis• Immune functionImmune function

Zinc DeficiencyZinc Deficiency

– Zinc deficiency often occurs in people with chronic digestive tract problems and exclusively breastfed infants.

– Associated with delayed sexual maturation and growth retardation

Zinc Content of Selected FoodsZinc Content of Selected Foods

Insert Table 9.16

Good Food Sources of ZincGood Food Sources of Zinc

Insert Figure 9.20

Zinc: Dietary Adequacy and Zinc: Dietary Adequacy and ToxicityToxicity

• AdequacyAdequacy• Adult RDA ranges from 8 to 13 mg/dAdult RDA ranges from 8 to 13 mg/d• Children between 6 to 11 yrs at risk of Children between 6 to 11 yrs at risk of

deficiencydeficiency

• ToxicityToxicity• Upper Limit (UL) = 40 mg/dUpper Limit (UL) = 40 mg/d• May reduce HDL cholesterol levelMay reduce HDL cholesterol level• >100 mg/d results in diarrhea, cramps, >100 mg/d results in diarrhea, cramps,

vomiting, and depressed immune systemvomiting, and depressed immune system

Iodide (I)Iodide (I)

Why is Why is IodideIodide Necessary? Necessary?

• Required for normal thyroid Required for normal thyroid function and production of the function and production of the thyroid hormone.thyroid hormone.

• The hormone controls the rateThe hormone controls the rate

of metabolism.of metabolism.

• Iodide is added to regular table Iodide is added to regular table salt to prevent deficiency.salt to prevent deficiency.

Iodide Content of Selected FoodsIodide Content of Selected Foods

Insert Table 9.17

Iodide: Dietary Adequacy and Iodide: Dietary Adequacy and Toxicity Toxicity

• AdequacyAdequacy• Adult RDA = 150 mcg/dAdult RDA = 150 mcg/d

• ToxicityToxicity• UL = 1.1 mg/d UL = 1.1 mg/d

• May result in enlargement of May result in enlargement of thyroid glandthyroid gland

Dietary Deficiency of IodideDietary Deficiency of Iodide

GoiterGoiter• Characterized by enlarged Characterized by enlarged

thyroid glandthyroid gland• Common before advent of Common before advent of

iodized salt in areas where iodine iodized salt in areas where iodine content of soil was poorcontent of soil was poor

CretinismCretinism• Condition affecting infants born to Condition affecting infants born to

women who were iodide deficient women who were iodide deficient during pregnancyduring pregnancy

Selenium (Se)Selenium (Se)

Why is Why is SeleniumSelenium Necessary? Necessary?

• Part of a group of proteins called Part of a group of proteins called selenoproteinsselenoproteins • Many selenoproteins are antioxidants.Many selenoproteins are antioxidants.

• May reduce risk of certain cancersMay reduce risk of certain cancers

Selenium Content of Selected FoodsSelenium Content of Selected Foods

Insert Table 9.18

Dietary Adequacy, Deficiency, Dietary Adequacy, Deficiency, and Toxicity of Seleniumand Toxicity of Selenium

• AdequacyAdequacy• Adult RDA = 200 mcg/dAdult RDA = 200 mcg/d• Most Americans meet the RDAMost Americans meet the RDA

• DeficiencyDeficiency• May occur with severe digestive tract May occur with severe digestive tract

conditionsconditions

• ToxicityToxicity• Upper Limit (UL) = 400 mcg/dUpper Limit (UL) = 400 mcg/d• Known as Known as selenosisselenosis

Chromium (Cr)Chromium (Cr)

Why is Why is ChromiumChromium Necessary? Necessary?• May enhance insulin’s action on cell May enhance insulin’s action on cell

membranesmembranes• ““Holds the door open” for glucose entry into Holds the door open” for glucose entry into

cellscells

Sources of ChromiumSources of Chromium• Widely distributed in foodsWidely distributed in foods

Dietary Adequacy Dietary Adequacy — most diets are adequate— most diets are adequateDeficiency Deficiency — causes impaired glucose tolerance— causes impaired glucose toleranceToxicity Toxicity — not known— not known

Chromium Content of Selected FoodsChromium Content of Selected Foods

Insert Table 9.16

Summary of Ultratrace MineralsSummary of Ultratrace Minerals

Insert Table 9.19

Chapter 9 HighlightBottled Water versus Tap Water

According to results of surveys, Americans drink bottled According to results of surveys, Americans drink bottled water:water:

Taste preferencesTaste preferences

ConvenienceConvenience

Drinking bottled water is expensive and Drinking bottled water is expensive and unnecessary, unless public water supply unnecessary, unless public water supply is disrupted. is disrupted.

What is Bottled Water?

FDA Definition:FDA Definition:

Water intended for human consumption Water intended for human consumption that is sealed in containers and has no that is sealed in containers and has no added ingredients other than a added ingredients other than a substance that prevents growth of substance that prevents growth of microbes, such as bacteria.microbes, such as bacteria.

Is Bottled Water Safe to Drink?

FDA regulates:FDA regulates:– Levels of contaminants in water such as Levels of contaminants in water such as

microbes, chemicals, and mineralsmicrobes, chemicals, and minerals– Requires water be sampled, analyzed, and Requires water be sampled, analyzed, and

found to be safe and clean before bottlingfound to be safe and clean before bottling

Is Tap Water Safe to Drink?

• TheThe Safe Drinking Water Act Safe Drinking Water Act requires water to requires water to undergo a thorough purification process and undergo a thorough purification process and be tested for safety constantly. be tested for safety constantly.

• If testing indicates water may pose a threat to If testing indicates water may pose a threat to public health, consumers are warned through public health, consumers are warned through media, and a “boil order” may be issued.media, and a “boil order” may be issued.• ““Boil order” Boil order” = boiling water for 10 minutes to kill = boiling water for 10 minutes to kill

harmful microorganismsharmful microorganisms

FDA Definitions for Classifying Some Types of Water

Insert Table Insert Table 9.A9.A