Nutrition Test 6

• n Bone
• structure

• q Provides
• strength to support the body

• q Allows
• for flexibility

• q Contains
• about 65% minerals providing the hardness of bone

• q Contains
• 35% organic structures for strength, durability, flexibility

• q Collagen:
• fibrous protein in bone tissue

• n Two
• types of bone tissue:

• q Cortical
• bone (compact bone)

• § Very
• dense tissue

• § Outer
• surface of bone

• § 80%
• of the skeleton.

• q Trabecular
• bone (spongy bone)

• § “Scaffolding”
• on the inside of bones

• § Supports
• cortical bone

• § 20%
• of the skeleton.

• n Bones
• develop through three processes:

• q Bone
• growth - increase in bone size

• § Completed
• by age 14 in girls and age 17 in boys

• q Bone
• modeling - shaping of bone

• § Completed
• by early adulthood

• § Exercise
• and overweight increase bone thickness

• q Bone
• remodeling - recycling of bone tissue

• n Bone
• remodeling involves:

• q Resorption
• – surface of bones is broken down by osteoclasts, cells that erode the
• surface of bones

• q Formation
• of new bone matrix by osteoblasts, cells that produce the
• collagen-containing component of bone that is then mineralized

• n Bone
• density (when bones strongest d/t density)

• q Peak
• bone density is reached before the age
• of 30

• q Remodeling
• maintains bone density during early adulthood

• q Density
• begins to decrease after age 40 because resorption exceeds new bone formation

n Dual energy X-ray absorptiometry (DEXA)

q Measures density with very low level x-ray

q Scans full body, or hips & spine

n Quantitative ultrasound

• q Uses sound waves to measure bone in heel, shin, and
• kneecap

n Peripheral DEXA (pDXA)

q Measures periphery – wrist, heel or fingers

n Single energy x-ray absorptiometry

q Measures wrist or heel

• n Calcium
• is the most abundant major mineral in the body

• n Bioavailability
• – the body’s ability to absorb & utilize calcium depends on:

• q Age
• & need for calcium

• q Amount
• of dietary calcium & vitamin D

• q Binding
• factors (phytates, oxalates) in food

Calcium absorption

• q Requires
• vitamin D

• q Is
• enhanced in an acid environment

• n Functions of
• calcium

q Form and maintain bones and teeth

q Assists with acid-base balance

q Transmission of nerve impulses

q Assist in muscle contraction

• q Maintain blood pressure, initiate blood clotting, and
• regulating various hormones and enzymes

• n Excellent
• sources include milk products

• q skim
• milk, low-fat cheese, nonfat yogurt

• n Other
• good sources include

• q Fortified
• foods (cottage cheese, orange juice)

• q Green
• leafy vegetables (kale, collard greens, broccoli, and cabbage are low in
• oxalates)

• q Fish
• with edible bones (sardines, salmon)

n Excess excreted form body

n Supplements can lead to mineral imbalances

• n Hypercalcemia (high blood calcium) can be caused by
• cancer or PTH overproduction; may lead to calcium deposits in soft tissues

n Osteopenia

n Osteoporosis

• n Hypocalcemia (low blood calcium) can be caused by
• kidney disease, vitamin D deficiency, or low PTH production

• n Vitamin
• D

• q Fat-soluble
• vitamin & a hormone

• q Excess
• is stored in liver and adipose tissue

• q Can
• be made by the body when skin is exposed to UV light

• q Considered
• a hormone since it is made in one location and acts in another location; made
• active in the liver & kidneys

• Vitamin D:
• Functions

• n Functions
• of vitamin D

• q Required
• for calcium and phosphorus absorption from the small intestine

• q Regulates
• blood calcium levels

• q
• Works with PTH to stimulate osteoclasts

• q Necessary
• for bone calcification

• n Food:
• Few food naturally contain high levels of vitamin D

• q Fatty
• Fish (salmon, tuna, herring, shark

• q Fortified
• milk (most reliable source)

• q Some
• fortified cereals & soy products

• n Sunlight:
• If optimum conditions

• q Exposure
• of unprotected hands, face & arms 20-30 min. two – three times/ week

• Vitamin D:
• Toxicity/Deficiency

n Results from supplements (5-10 X AI)

• n Hypercalcemia (hi blood Ca) S/S: weakness, loss of
• appetite, mental confusion; calcium deposits in soft tissues; increased bone
• loss

n ↓ bone mass & demineralization of bone

n Rickets – Vit D deficiency disease in children

n Osteomalacia – Vit D deficiency disease in adults

n Osteoporosis – can result from Vit D deficiency



n Causes: diseases that cause malabsorption of fat

• n Vitamin
• K

• q Fat-soluble
• vitamin stored in the liver

• q Part
• of family compounds known as quinones; comes from plants & produced by
• healthy bacteria in the large intestine

• n Functions
• of vitamin K: serves as coenzyme in production of specific proteins

• q Blood
• coagulation

• q Bone
• turnover

• Vitamin K:
• Sources

• n Good
• Food Sources: green leafy veggies, veggie oils such as soybean &
• canola

• n Healthy
• bacteria in large intestine produce small amounts of vitamin K

• Vitamin K:
• Toxicity/Deficiency

n No know side effects of consuming excessive Vit K

n Reduced blood clotting, excessive bleeding

• n May be caused by: long term antibiotic use; fat
• malabsorption diseases

• n Newborns – given vit K at birth d/t lack of bacteria
• in GI tract

• n Phosphorus
• (as phosphate) is the major intracellular negatively charged electrolyte

• n Functions
• of phosphorus

• q Part
• of mineral complex of bone

• q Required
• for proper fluid balance

• q Component
• of ATP, DNA, cell membranes & lipoproteins

• Phosphorus:
• Sources

• n Widespread
• in many foods

• q High
• in protein-containing foods such as milk, meats, eggs

• q In
• processed foods as a food additive

• q In
• soft drinks as phosphoric acid

• Phosphorus:
• Toxicity/Deficiency

• Excessive Vit D supplements or
• phosphorus-containing antacids can cause high phosphorus levels, muscle spasms
• and convulsions

• The effect on bone loss is not conclusive –
• additional research needed

n Rare

• n About 50 – 60% of the body’s magnesium is found in the
• bones

n Major mineral

• n
• Functions of magnesium

q A mineral found in bone structure

q Cofactor for over 300 enzyme systems

q Required for ATP, DNA, and proteins

• q Supports vitamin D metabolism, muscle contraction, and
• blood clotting

• Magnesium:
• Sources

Seafood & green leafy veggies

Whole grains, seeds & nuts

• High fiber & plant phytates
• inhibit absorption

• High protein rich diets enhance
• absorption

Magnesium: Toxicity/Deficiency

n No toxicity from magnesium in food

• q Excess magnesium supplements can cause diarrhea,
• nausea, cramps, dehydration

n Poor intake can contribute to:

q Low blood calcium

q Muscle cramps & seizures

q Long term associated with osteoporosis

• n Fluoride
• is a trace mineral.

• q Ionic
• form of fluorine

• q About
• 99% of the body’s fluoride is stored in teeth and bones

• n Functions
• of fluoride

• q Development
• and maintenance of teeth and bones

• q Combines
• with calcium and phosphorus to protect teeth from bacteria

Fluoride: Sources

Sources of fluoride

• q Fluoridated
• dental products

• q Fluoridated
• water

• Fluoride:
• Toxicity/Deficiency

• q Fluorosis (excess
• fluoride) creates porous tooth enamel; teeth become stained and pitted

Deficiency results in dental caries

• n Decreased
• bone mass where no obvious disease can be found -

• n Osteoporosis
• is a disease characterized by

• q Low
• bone mass

• q Deterioration
• of bone tissue

• q Fragile
• bones leading to bone fractures

• q Compaction
• of bone; decreased height

• q Shortening
• and hunching of the spine

Osteoporosis: Risk Factors

• n Factors
• influencing the risk of osteoporosis include:

q Age

q Gender

q Genetics

q Nutrition

• q Physical
• activity

Osteoporosis: Risk Factors

• n Age is a
• risk factor for osteoporosis

q Bone mass decreases with age

q Age-related hormonal changes influence bone density

q Older adults are less able to absorb vitamin D

• n Gender
• is a risk factor for osteoporosis.

q 80% of Americans with osteoporosis are women

q Women have lower bond density than men

• q Low estrogen production increases bone loss:
• post-menopausal women and adolescent girls engaged in extreme dieting

Osteoporosis: Risk Factors

n Smoking and poor nutrition increase osteoporosis risk

• q Cigarette smoking effects hormones that influence bone
• formation & resorption

q Alcoholism is associated with fractures

q Caffeine may increase urinary calcium loss

n Physical activity

• q Regular exercise stresses bone tissues, stimulates
• increases in bone density

• q Weight-bearing activities (walking, jogging) are
• especially helpful in increasing bone mass

• q Improved muscle strength & physical stability
• reduces the risk of falling & bone fractures

Osteoporosis

• n Female
• athlete triad is a condition characterized by:

• q Eating
• disorder

q Amenorrhea

q Osteoporosis

Osteoporosis

• n There
• is no cure for osteoporosis.

• n The
• progression of osteoporosis may be slowed by

• q Adequate
• calcium and vitamin D intake

• q Regular
• exercise

• q Anti-resorptive
• medications

n Functions

• q Transport
• of oxygen and nutrients to cells

• q Removal
• of waste products from tissues

• Blood:
• composition

• n Components
• of blood

• q Erythrocytes
• – red blood cells for transporting oxygen through the body

• q Leukocytes
• – white blood cells of the immune system

• q Platelets
• – cell fragments that assist in blood clotting

• q Plasma
• – the fluid portion of the blood for maintaining adequate blood volume

Blood

• n Iron
• is a trace mineral – needed in very small amounts however: Iron deficiency
• anemia is most common nutrient deficiency in world

• n Functions
• of iron

• q A
• component of the protein hemoglobin which carries oxygen in erythrocytes

• q A
• component of myoglobin which carries oxygen in muscle cells

• q A
• coenzyme involved in energy metabolism of carbohydrates, fats, and proteins

Iron

• n Two
• types of iron are found in foods

• q Heme
• iron – found in animal based foods and more absorbable (meat, poultry,
• fish, clams, oysters)

• q Non-heme
• iron – not easily absorbed (fortified cereals & breads and animal
• products)

Iron

• n Factors
• that promote iron absorption

• q Meat
• factor

• q Stomach
• acids

• q Vitamin
• C

• n Factors
• that impair iron absorption

• q Phytates,
• polyphenols, vegetable proteins, fiber, and calcium

Iron

n How Is Iron Transported in the Body?

• q Transferrin is
• the primary iron-transport protein in the blood

• q Receptors on cell surface enable iron transport into
• the cell

n What Factors Regulate Total Body Iron?

q Iron absorbed

q Iron loss

q Storage and recycling of body iron

• Iron:
• Toxicity/Deficiency

• n Accidental iron overdose is the most common cause of
• poisoning deaths in children

• q Toxicity
• : S/S nausea, vomiting, diarrhea, dizziness, confusion

• q Delayed treatment: severe damage to the heart, central
• nervous system, liver, kidneys

q Hemochromatosis: excessive absorption of dietary iron and altered iron storage

n Most common nutrient deficiency in world

• n Hi risk people: infants, young children, preadolescent
• girls, premenopausal women, and pregnant women

• n Zinc
• is a trace mineral; <100mg/dy needed

• q Food
• sources: red meats, some seafood, whole grains, enriched grains and cereals

• n Functions
• of zinc

• q Coenzyme
• for hemoglobin production

• q Maintain
• protein structures: important in the development and function of immune system

• q Regulate
• gene expression

• Zinc:
• inhibit/enhance absorption

• n Dietary factors that inhibit zinc
• absorption

q High non-heme iron intake

q Phytates and fiber (whole grains, beans)

• n Dietary factors that enhance zinc
• absorption

q Animal based protein

• Zinc:
• Toxicity/Deficiency

• q Toxicity
• can occur from supplements

q Symptoms: intestinal pain, cramps, nausea, vomiting

q Depressed immune function

q Interference with copper and iron absorption.

q Deficiencies are uncommon in the US

• q S/S: growth retardation, diarrhea, delayed sexual
• maturation, infections

• n Copper
• is a trace mineral

• q Food
• sources: Organ meats, seafood, nuts, seeds, whole grain foods

• n Functions
• of copper

• q Coenzyme
• for energy metabolism, and for collagen production

• q Part
• of superoxide dismutase antioxidant enzyme system

• q Required
• for iron transport

Copper: Absorption

n Factors that promote copper absorption

q More copper is absorbed with a low-copper diet



n Factors that impair copper absorption

q High zinc intakes

q High iron intakes

Copper: Toxicity/Deficiency

Toxicity is not well studied in humans

• q S/S: intestinal pain, cramps, nausea, vomiting, liver
• damage

q Copper deficiency is rare

• q S/S: anemia,
• reduced white blood cells, osteoporosis in children

• n Vitamin
• K is a fat-soluble vitamin

• q Sources:
• Green leafy veggies, such as collard greens, kale, spinach, cabbage

• n Function
• of vitamin K

• q Coenzyme
• that assists in the synthesis of blood coagulating proteins, prothrombin and
• procoagulants, factors VII, IX, and X

• Vitamin K:
• Absorption

• n promote
• vitamin K absorption

q Gastrointestinal bacteria produce vitamin K

• q The amount of dietary vitamin K needed depends on
• intestinal health

• n Impair
• vitamin K absorption

q Impaired dietary fat absorption

• Vitamin K:
• Toxicity/Deficiency

• q No known side effects from consuming large amounts of
• vitamin K

q Blood fails to clot, bleeding, hemorrhaging

q Fat malabsorption reduces vitamin K absorption

q Newborns lack intestinal bacteria

• n Folate
• is a water-soluble vitamin

• n Bioavailability
• depends on source: better from supplements & fortification – less from food

• q Sources:
• breads, flours, pasta, grain products are fortified; liver, spinach, lentils,
• oatmeal, asparagus

• n Functions
• of folate

• q DNA
• synthesis, amino acid metabolism

• q Critical
• for cell division of very early embryos

• q Functions
• with B12 and B6 metabolism

• Folate:
• Toxicity/Deficiency

• q Toxicity
• can occur with supplements

q Toxicity can mask vitamin B12 deficiency

• q Symptoms are intestinal pain, cramps, nausea,
• vomiting, liver damage

q Severe deficiency :Macrocytic anemia

q Elevated homocysteine

• q Neural tube defect in developing embryo of pregnant
• woman

• n Vitamin
• B12 is a water soluble vitamin

• q Requires
• acidic environment (stomach) and protein intrinsic factor (IF) for absorption

• q Stored
• in the liver

• n Functions
• of vitamin B12

• q Coenzyme
• for DNA synthesis

• q Maintains
• myelin sheath of nerve fibers

• q Metabolism
• of amino acid homocysteine

Vitamin B12 : Sources

• n Sources
• of vitamin B12

• q Available
• exclusively from animal sources

• q Vegan
• diet may obtain vitamin B12 from fortified foods, supplements, or
• injections

Vitamin B12 : Toxicity/Deficiency

q No known adverse effects of excess

• q Deficiency
• is rare

q Gastrointestinal & neurologic effects

q Pernicious anemia

• n A woman’s need for folate
• dramatically increases during pregnancy.

• q Critical, very early in
• pregnancy

• n Folate is required for cell
• division and proper formation of the neural tube.

• n The neural tube develops
• into the brain and spinal cord.

• n All women capable of
• becoming pregnant should consume an additional 400 micrograms of folate daily

• n Folate and vitamin B12
• are required for the breakdown of the amino acid homocysteine

• n Low folate and vitamin B12
• intake may increase the level of homocysteine

• n High homocysteine levels are
• associated with greater cardiovascular and cerebrovascular disease risk

• n
• Iron-deficient
• Anemia

• q Results in small red blood cells that do not contain
• enough hemoglobin

• q S/S: fatigue, pale skin, impaired work performance,
• depressed immune function, impaired memory

• n
• Pernicious
• Anemia

q Occurring after the loss of specific cells of stomach

• q Primary cause of vita B12 deficiency is the
• lack of intrinsic factor (IF)

q Occurs d/t low B12 in diet

q S/S: pale skin, reduced energy, fatigue

• Anemia:
• continued

• n
• Macrocytic
• (megaloblastic) Anemia

q caused by severe folate deficiency

• q Results in enlarged red blood cells containing
• insufficient hemoglobin

• q S/S: common symptoms of anemia including: weakness,
• fatigue, difficulty concentrating, irritability, headache, shortness of breath

• n What
• Is the Immune System?

• q A
• healthy immune system protects the body from infectious diseases, helps heal
• wounds, and guards against the development of cancers

• n How
• Does It Function?

• q Nonspecific
• immune function

• q Specific
• immune function

Immune System

• n How
• does nutrition affect the immune system?

• q A
• nourishing diet provides all the nutrients the immune system needs

• q Single-nutrient
• subclinical deficiencies can cause subtle abnormalities in immunity

• q Protein/energy
• malnutrition and severe deficiencies of several micronutrients result in
• functional immunodeficiency

n Protein/energy malnutrition impairs immune function

q Malnutrition increases the risk for infection

• q Infection depresses appetite and often causes vomiting
• and diarrhea

• q Decreased appetite, vomiting, and/or diarrhea cause
• malnutrition which increases vulnerability to infection

• q Anergy is
• the diminished ability of the immune system to respond to antigens

• n Essential fatty acids are precursors for signaling
• molecules eicosanoids

q Omega 6 FA’s produce inflammatory mediators

q Omega 3 FA’s help relieve inflammation

• q Vitamin A
• protects the barrier function of the mucosa

• q
• Vitamin C and vitamin E protect phagocytes from reactive
• oxygen species

• q Zinc assists
• immune cell gene expression & protein synthesis

• q Copper
• deficiency reduces lymphocyte proliferation

• q Iron deficiency
• & iron overload both impair immune function

• q Selenium
• deficiency & toxicity impair immune function

• n Probiotics,
• food or supplements that contain live bacteria, are thought to protect against
• pathogens by:

• q Colonizing
• the gut

• q Inhibiting
• growth of pathogens

• q Stimulating
• immune response

• n Prebiotics
• are nondigestible fibers in foods that are fermented by beneficial bacteria and
• promote their multiplication (food for healthy bacteria)