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Unit 6 Bone, Blood, and Immunity Health
Bone Health
Bones
Bones are living _____________ that contain
Bone tissue
_______________
______________
_________________ tissue
Blood vessels supply ___________________ to bone to support its activities
Bone provides strength and flexibility
Contains about ____% minerals, providing the hardness of bone
Contains ____% organic structures for strength, durability, and flexibility
__________________: fibrous protein in bone tissue
________________________: mineral crystals around collagen designed to bear weight
Bone Health
Two types of bone tissue:
________________ bone (____________________ bone)
Very _________ tissue
Outer surface of bone
80% of the skeleton.
____________________ bone (_________________ bone)
“___________________” on the inside of bones
Supports cortical bone
20% of the skeleton.
Faster turnover rate (sensitive to hormonal changes and nutritional deficiencies)
Bones develop through three processes:
Bone _______________ - increase in bone size
Completed by age 14 in girls and age 17 in boys
Bone _______________ - shaping of bone
Completed by early adulthood
Exercise and overweight increase bone thickness
Bone ______________________ - recycling of bone tissue
Bone remodeling involves:
______________________ – surface of bones is broken down by ______________________,
cells that erode the surface of bones
Formation of new bone matrix by ____________________, cells that produce the collagencontaining component of bone that is then mineralized
Bone density (compactness of bones)
Peak bone density is reached before the age of _____
when bones are ___________
Remodeling maintains bone density during early adulthood
Density begins to __________________ after age 40 because __________________ exceeds new bone
formation
Factors associated with a lower peak bone density:
Late pubertal age in boys
Late onset of menstruation in girls
Inadequate calcium intake
Low body weight
Physical inactivity during the pubertal years
What are the methods of measuring bone density?
Dual energy X-ray absorptiometry (_______)
Measures bone density with very low level X-ray energy
Scans the full body, or hips and spine
Is a non-invasive procedure
Results are compared with average peak bone density of 30-year old healthy adult
____-score is used to assess a person’s risk for fracture and diagnose osteoporosis
Recommended for postmenopausal women
Quantitative ______________________ technique
Uses sound waves to measure density in the heel, shin and kneecap
_____________________ dual energy x-ray absorptiometry
Similar to DXA but only measures wrist, heel or finger
Nutrients Involved in Bone Health
Calcium is the most recognized nutrient associated with bone health
Also essential for bone health:
Calcium (____)
Calcium is the most ________________ major mineral in the body
Calcium absorption
Is enhanced in an _____________ environment
Requires 1,25-dihydroxyvitamin D
Functions of calcium
Provides ________________ for bones and teeth
Assists with acid−base ___________________
Transmission of nerve impulses
Assists in ________________ contraction
Maintains healthy blood pressure
Initiates blood clotting
Regulates hormones and enzymes
Recommended dietary intake
Adequate Intake (AI) vary with age and gender from 1,000 mg to 1,300 mg per day
Upper Limit (UL): 2,500 mg
________________________ – the body’s ability to absorb and utilize calcium depends on
The individual’s age and need for calcium
The amount of dietary calcium and vitamin D
Binding factors (phytates, oxalates) in foods
Excellent sources include milk products
skim milk, low-fat cheese, nonfat yogurt
Other good sources include
__________________ foods (cottage cheese, orange juice)
Green leafy vegetables (kale, collard greens, broccoli, and cabbage are low in oxalates)
Fish with edible bones (sardines, salmon)
What if you consume too much calcium?
Excess dietary calcium is __________________________ in feces
Mineral imbalances from supplements
____________________________ (high blood calcium) can be caused by cancer or PTH
overproduction
Symptoms: fatigue, appetite loss, constipation, mental confusion, calcium deposits in soft tissues
What if you don’t consume enough calcium?
_____________________ from long-term calcium deficiency
______________________ (low blood calcium) can be caused by kidney disease, vitamin D
deficiency, or low
PTH production
Symptoms: muscle spasms and convulsions
Osteoporosis is a disease characterized by
low bone mass
deterioration of bone tissue
fragile bones leading to bone-fracture risk
bone compaction: decreased height
shortening and hunching of the spine: kyphosis (dowager's hump)
Factors influencing the risk of osteoporosis include:
____________
Bone mass decreases with age
Age-related hormonal changes influence bone density
Decreased vitamin D metabolism with age
Factors influencing the risk of osteoporosis include:
_______________
80% of Americans with osteoporosis are women
Women have lower bone density than men
Low estrogen production increases bone loss: post-menopausal women and adolescent girls
engaged in extreme dieting
At risk: Caucasian women of low body weight with first-degree relative (mother or sister) with
osteoporosis
______________ and poor __________________ increase osteoporosis risk
Cigarette smoking effects hormones that influence bone formation and resorption
Alcoholism is associated with fractures
Caffeine may increase urinary calcium loss
Dietary protein and calcium interaction
Low calcium and vitamin D intakes result in low bone density
_________________________________
Regular exercise stresses bone tissues, stimulates increases in bone density
Weight-bearing activities (walking, jogging) are especially helpful in increasing bone mass
Improved muscle strength and physical stability reduces the risk of falling and bone fractures
Nutrition and Osteoporosis
Fruit and vegetable consumption associated with improved bone health
good sources of vitamins C and K, and magnesium
Protein: effect on bone health is controversial
high intake may increase calcium loss
low-protein intake also associated with bone risks
Calcium & vitamin D are important throughout the life span
Sodium: high intakes appear to have a negative impact, but studies are inconclusive
Osteoporosis
There is ______________________ for osteoporosis.
The progression of osteoporosis may be _____________________ by
Adequate calcium and vitamin D intake
Regular (weight-bearing) exercise
Resistance training
Anti-resorptive medications (may have side affects)
Vitamin D
_____________-soluble vitamin
Excess is stored in liver and adipose tissue
Can be synthesized by the body by exposure to ______ light from the sun
Considered a _________________: synthesized in one location and regulates activities in other parts of
the body
Functions of vitamin D
Regulates blood calcium levels (regulates calcium and phosphorus absorption from the small
intestine)
Stimulates ______________________ when calcium is needed elsewhere in the body
Required for bone _________________________
Recommended intake
AI: assume sun exposure is inadequate
Inadequate sun in the winter (latitude of more than 40°N or more than 40°S)
Darker skin (more melanin pigment) reduces the penetration of sunlight
People >65 years: decreased capacity to synthesize vitamin D from the sun
Obesity: lower circulating vitamin D levels
RDA: 600 IU for men/women ages 19 to 70; 800 IU for adults over age 70
UL: 4,000 IU for everyone over 9 years of age
Controversy: recent evidence suggests that the current RDA is not sufficient to maintain optimal
bone health and reduce the risks for diseases such as cancer
Sources of vitamin D
Ergocalciferol (D2)—plants, supplements
Cholecalciferol (D3)—animal foods, sun
Most foods naturally contain little vitamin D
Mostly obtained from fortified foods (e.g., milk)
High amounts: cod liver oil, fatty fish (salmon, mackerel, and sardines)
Vegetarians not consuming milk products receive vitamin D from the sun, fortified soy or cereal
products, or supplements
What if you consume too much vit D?
Can occur from vitamin supplements
Results in ___________________ (high blood calcium)
What if you don’t consume enough vit D?
Can occur with diseases that reduce intestinal absorption of fat
__________________ – occurs in children
__________________ – occurs in adults
Medications alter vitamin D metabolism and activity: glucocorticoids, phenobarbital
Vitamin K
Fat-soluble vitamin stored in the liver
________________ – plant form of vitamin K
___________________ – form of vitamin K produced by bacteria in the large intestine
Functions of vitamin K
Blood ________________________
______________ metabolism
"Gla" protein production
Osteocalcin: secreted by osteoblasts (bone remodeling)
Matrix Gla protein: in protein matrix of bone, cartilage, blood vessel walls, soft tissues
Recommended intake
There is ___ RDA for vitamin K
AI values are 120 mg/day for men and 90 mg/day for women
Sources of vitamin K
Synthesized by bacteria in the large intestine
Green leafy vegetables, vegetable oils
What if you consume too much vit K?
No known side effects from large quantities
What if you don’t consume enough vit K?
_______________ blood clotting, excessive bleeding
Fat malabsorption (celiac disease, Crohn's disease, and cystic fibrosis)
Long-term use of _________________ can lead to deficiency
Injection of vitamin K at birth for newborns
Phosphorus (___)
Phosphorus (as phosphate) is the major intracellular negatively charged ___________________
An essential component of all cells, found in both plants and animals
Functions of phosphorus
Critical to mineral composition of __________________
Required for proper fluid balance
Component of ATP, DNA, membranes
Recommended intake
RDA for phosphorus is 700 mg/day
Sources of phosphorus
High in ________________-containing foods such as milk, meats, eggs
In processed foods as a food additive: smoothness, binding, and moisture retention
In soft drinks as phosphoric acid (milk-displacement effect)
What if you consume too much phosphorus?
Excessive vitamin D supplements or phosphorus-containing antacids can cause high phosphorus
levels, muscle spasms, and convulsions
What if you don’t consume enough phosphorus?
Deficiencies are rare in healthy adults
Can occur in alcohol abuse, premature infants, and elderly people with poor diets
Magnesium (_____)
About ____________% of the body’s magnesium is found in the bones
Functions of magnesium
A mineral found in bone structure
Cofactor for over _______ enzyme systems
Required for ATP, DNA, and proteins
Supports vitamin D metabolism, muscle contraction, and blood clotting
Required for ________ activation
Recommended intake
RDA varies based on age and gender
UL (pharmacological): 350 mg/day
Sources of magnesium
Green leafy vegetables, whole grains, seeds, nuts, seafood, beans, some dairy products
Dietary protein enhances absorption and retention
What if you consume too much magnesium?
Excess supplements cause diarrhea, nausea, cramps, dehydration, acid–base imbalances
________________ occurs in individuals with impaired kidney function (antacid)
What if you don’t consume enough magnesium?
__________________: results in hypocalcemia; associated with osteoporosis, heart disease, high
blood pressure, type 2 diabetes
Fluoride (___)
Fluoride is a ____________ mineral.
About 99% of the body’s fluoride is stored in teeth and bones
Functions of fluoride
Development and ____________________ of teeth and bones
Combines with calcium and phosphorus to protect teeth from bacteria
Recommended intake
AI varies by gender and increases with age, ranging from 1-4 mg/day
Sources of fluoride
Fluoridated _______________________
Fluoridated ____________
What if you consume too much fluoride?
__________________ (excess fluoride) creates porous tooth enamel; teeth become stained and pitted
What if you don’t consume enough fluoride?
Dental caries (cavities)
Blood Health
Blood
Blood is the only ________________ tissue in the body
Functions
________________ of oxygen and nutrients to cells
Removal of ______________ products from tissues due to metabolic reactions
Components of blood
__________________—red blood cells transport oxygen through the body
__________________—white blood cells are key to our immune system
__________________—cell fragments assist in blood clotting
__________________—fluid portion of the blood maintains adequate blood volume
Nutrients Involved in Blood Health and Immunity
Iron (____)
Iron is a _______________ mineral
Functions of iron
Component of oxygen-carrying ________________ and ___________________ (muscle)
Component of _________________, electron carriers within the metabolic pathways for energy
production from carbohydrates, fats, and protein
Maintaining Iron Homeostasis
Regulation of iron digestion, absorption, transport, storage, and excretion
Factors that alter iron digestion and absorption
Individual's iron status
Level of dietary iron consumption
Type of iron in foods
Amount of stomach acid for digestion
Dietary factors enhance or inhibit absorption
Two types of iron in foods
___________ iron—found only in animal-based foods and more absorbable
_______________ iron—not as easily absorbed
Factors that promote iron absorption
____________ factor
Stomach _____________
Vitamin C
Factors that impair iron absorption
Phytate (legumes, rice, and whole grains)
Polyphenols (oregano, red wine, tea, coffee)
Vegetable proteins
Bioavailability of iron from vegan diet is approx. 1-10%, vs. typical Western diet's absorption of 14−18%
Iron transport
__________________: iron-transport protein in blood
Receptors on cells transport iron into cells
Iron storage
______________ and hemosiderin help meet iron needs
Liver, bone marrow, and spleen
Regulation of total-body iron:
Iron ____________________
Iron losses
Storage and recycling of iron
Recommended intake
RDA varies based on age and gender
__ mg/day for adult men
____ mg/day for pregnant women
Sources of iron
Meat, poultry, fish, clams, oysters, enriched or fortified cereals and breads
Supplements
What if you consume too much iron?
Accidental iron overdose is the most common cause of poisoning deaths in children
_________________________:
Overabsorb iron→Deposition in tissues
Consequences of toxicity
Stomach irritation
Increased formation of free radicals
________________ due to respiratory collapse (shock)
Treatment: reduce dietary iron, avoid high vitamin C intake, blood removal
What if you don’t consume enough iron?
Most common nutrient _______________ in the world
High risk: infants, young children, adolescent girls, premenopausal and pregnant women
Poor dietary intakes
Iron losses in blood and sweat
Diets high in fiber or phytates that bind iron
Low stomach acid
Poor iron absorption (poor gut health or dietary supplements with high mineral levels, e.g., calcium)
Stages of Iron Deficiency
1. ________________ is caused by a decrease in iron stores
2. Iron-deficiency __________________ occurs with decreased iron transport
3. Iron-deficiency ____________ results in reduced normal, healthy red blood cell production,
decreased size, inadequate hemoglobin
Zinc (____)
Zinc is a _______________ mineral.
Functions of zinc
Component of enzymes (______________ synthesis)
Maintain _______________ integrity and shape of proteins
Assist in regulating gene ___________________
Recommended intake
RDA is 8 mg/day for women, 11 mg/day for men
Absorption increases with need: growth, sexual development, pregnancy
Dietary factors inhibit zinc absorption
_______________ non-heme iron intake
_______________ and fiber (whole grains, beans)
Dietary factor enhances zinc absorption
Animal-based ________________
Sources of zinc
Red meats, some seafood, whole grains, enriched grains and cereals
What if you consume too much zinc?
Toxicity can occur from supplements
Symptoms: intestinal pain, cramps, nausea, vomiting
Depressed ________________ function
________________ high-density lipoprotein concentrations
Interference with copper and iron absorption
What if you don’t consume enough zinc?
Deficiencies are uncommon in the United States
Symptoms: growth retardation, diarrhea, delayed sexual maturation, hair loss, impaired appetite,
infections
Lack of good assessment parameters for zinc
Copper (____)
Copper is a ___________ mineral
Functions of copper
Required for __________ transport
__________________ in energy metabolism and for connective tissue production
Part of _______________________ antioxidant enzyme system
Regulates ________________________ (serotonin)
Factors that promote copper absorption
More copper is absorbed with low-copper diet
Factors that impair copper absorption
High _________ intakes
High _________ intakes
Recommended intake
RDA for adults is 900 µg/day
Sources of copper
Organ meats, seafood, nuts, seeds, whole grain foods
What if you consume too much copper?
Toxicity is not well studied in humans
Symptoms: abdominal pain, nausea, diarrhea, vomiting, liver damage (Wilson disease)
What if you don’t consume enough copper?
Copper deficiency is __________
Symptoms: anemia, reduced white blood cells, osteoporosis (children—bone demineralization)
Vitamin K
Vitamin K is a fat-soluble vitamin important for both bone and blood health
Function of vitamin K
Coenzyme assists in synthesizing blood _______________ proteins: prothrombin and
procoagulants, factors VII, IX, and X
Factors that promote vitamin K absorption
Gastrointestinal _____________ produce vitamin K
Dietary need depends on _____________ health
Factors that impair vitamin K absorption
Impaired dietary _________ absorption
Recommended intake
AI for adults is 90-120 µg/day
No established UL at this time
Sources of vitamin K
Green leafy vegetables, such as collard greens, kale, spinach, cabbage
Soybean and canola oils
What if you consume too much vitamin K?
No known side effects
What if you don’t consume enough vitamin K?
Deficiency is rare
Blood fails to ___________, bleeding, _______________________
Fat ______________________
Newborns lack intestinal bacteria to produce vitamin K (injection at birth)
Folate
Folate is a _____________-soluble vitamin
Functions of folate
__________ synthesis, amino acid metabolism
Cellular _________________ and ________________
Functions with B12 and B6 metabolism
Factors that alter folate digestion, absorption, and balance
Bioavailability depends on its source: better from supplements than from food
Alterations in folate status mimic those of iron
Four states of folate deficiency:
1) Negative folate balance (stage I)
2) Folate depletion (stage II)
3) Folate deficiency erythropoiesis (stage III)
4) Folate deficiency anemia (stage IV)
Recommended intake
RDA for adults is 400 µg/day, 600 µg/day during pregnancy
Sources of folate
Fortification to minimize birth defects: enriched breads, flours, pasta, grain products
Liver, spinach, lentils, oatmeal, asparagus
Heat-sensitive, can be leached out in cooking liquid
What if you consume too much folate?
Toxicity can result from supplements
Toxicity can ___________ vitamin B12 deficiency
Symptoms: intestinal pain, nausea, vomiting
What if you don’t consume enough folate?
_______________ anemia
Elevated ___________________
______________ tube defect
Folate's role in neural tube defects (NTDs)
Need for folate increases during _________________
NTDs = most common malformations of the CNS during embryonic and fetal development
Most common NTD is _______________________
Biggest challenge: NTDs occur early in pregnancy, sometimes before the pregnancy is known
Why?
Hence, adequate folate intake is important for sexually active women of childbearing age
Folate's role in macrocytic anemia
_______________ anemias = larger than normal red blood cells that inhibit adequate oxygen
transport
Symptoms include fatigue, irritability, difficulty concentrating, headaches, shortness of breath,
reduced capacity for work
Similar symptoms can result from vitamin B12 deficiency, so it's important to distinguish the
cause
Vitamin B12
Vitamin B12 is a _____________ soluble vitamin
Functions of vitamin B12
_______________ for DNA synthesis
Maintains _______________ sheath of nerve fibers
_________________ of amino acid homocysteine
Factors that alter vitamin B12 digestion, absorption, and balance
Requires acidic environment (stomach) and protein _____________________ for absorption
Stored in the liver
Four levels of vitamin B12 deficiency
Recommended intake
RDA for adults is 2.4 µg/day
Sources of vitamin B12
Found primarily in dairy products, eggs, meats, poultry, fish, and shellfish (animal sources)
Vegan diet may obtain vitamin B12 from fortified foods, supplements, or injections
What if you consume too much vitamin B12?
No known adverse effects
What if you don’t consume enough vitamin B12?
Deficiency is rare, but associated with dietary insufficiency or reduced absorption
Gastrointestinal and neurologic effects
Pernicious anemia (lack intrinsic factor)
_____________ anemia
Vitamin B12 role in _____________________ anemia
Special form of anemia occurring after the ___________ of specific cells of the stomach
Primary cause of vitamin B12 deficiency is the ____________ of intrinsic factor
Also occurs in people who consume very little vitamin B12 in their diet
Symptoms are pale skin, reduced energy, fatigue, neurological symptoms
Vascular Disease
Folate and vitamin B12 are required for the breakdown of the amino acid _________________
Low folate and vitamin B12 intake may increase the level of homocysteine
High homocysteine levels are associated with greater ________________ and _____________________
disease risk
Immune System
What Is the Immune System?
A healthy immune system ...
Protects the body from _____________ diseases
Helps _____________ wounds
Guards against the development of _________________
How Does It Function?
_____________________ immune function
Body's primary defense against microbes, airborne particles, venom, ingested toxins
Also called ________________ immunity
Intact skin and healthy mucous membranes
Stomach acid destroys food-borne bacteria
Inflammatory response causes discomfort, loss of appetite, fatigue, and fever
A _____________________ is a type of nonspecific immune cell. The one shown here is about to
engulf an invading microbe.
_____________________ immune function
Directed against recognized ___________________
Induces antibodies to destroy invader
___________________ cells remain in circulation
Two main types of cells: _____ cells and _____ cells
Acquiring specific immunity
Have disease or vaccinations (________________________)
________________ antibodies
____________________ injection (snakebite)
Malfunction can cause chronic inflammation and infection
________________ reactions
________________ response
Common in malnourished
_____________________
How does nutrition affect the immune system?
A nourishing diet provides all the nutrients the immune system needs
Single-nutrient subclinical deficiencies can cause subtle abnormalities in immunity
Protein/energy malnutrition and severe deficiencies of several micronutrients result in functional
immunodeficiency
Protein/energy malnutrition impairs immune function
Malnutrition increases the risk for ________________
Infection depresses _________________ and often causes vomiting and diarrhea
Decreased appetite, vomiting, and diarrhea cause malnutrition, which increases vulnerability to infection
Decreased __________________________ is a sensitive indicator of reduced nutritional status
Overnutrition/Obesity increases incidence and severity of infections
Increases __________________ of infections
________________ wound healing
Poor _____________________ response to vaccination
Inflammatory state may increase asthma, hypertension, cardiovascular disease, and type 2 diabetes among
obese individuals
Essential fatty acids make signaling molecules for the immune system
Essential fatty acids are precursors for signaling molecules ___________________________
Omega-6 fatty acids promote inflammatory response to help contain infection
Omega-3 fatty acids diminish inflammation in blood vessels (prevent heart disease)
Certain vitamins and minerals are critical to a strong immune response
Vitamin ___ maintains mucosal surface
Vitamins ___ and ____ protect cell membrane from reactive _____________ species
Zinc assists immune cell gene ________________ and enzyme activation (B and T cell proliferation)
___________: growth factor for immune cells
___________ deficiency impairs immune function
_________________:
Coenzyme for glutathione peroxidase
Promotes B and T cell proliferation
Antibody production
Excessive amounts can impair immunity