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Nutritional Aspects of Health > Exam 4 - Nutrition > Flashcards

Exam 4 - Nutrition Flashcards

1
Q

essential organic compounds needed in small amount

A
  • not synthesized by body
  • measurable decline in health if missing from diet
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2
Q

13 total vitamins

A
  • Fat soluble: A, D, E, K
  • Water soluble: B and C
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3
Q

Vitamins needed for

A
  • energy metabolism
  • growth
  • development
  • maintenance
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4
Q

Fat-soluble vitamins are absorbed with:

A
  • dietary fats
  • adequate absorption depends on bile and pancreatic lipase
  • 40-90% absorbed under optimal conditions
  • diseases and drugs such as orlistat can impair absorption
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5
Q

water soluble vitamins absorption

A

not dependent on dietary fats: 90-100% absorption rate

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6
Q

all vitamins

A
  • digestive process in the stomach begin the release of vitamins from food
  • digestive enzymes produced by the pancreas aid in the release of vitamins from food
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7
Q

Fat-soluble vitamins only

A
  • bile produced in the liver and stored in the gallbladder aids in fat-soluble vitamin absorption
  • fat-soluble vitamins are absorbed in the small intestine, along with dietary fat, and carried by chylomicrons into the lymphatic system
  • absorbed in the small intestine and released directly into the blood
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8
Q

vitamin K only

A

small amounts of vitamin K are made by bacteria in the ileum of the small intestine and in the large intestine

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9
Q

Storage of fat-soluble vitamins

A
  • stored in the liver and adipose tissue
  • less storage of vitamin K
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10
Q

Storage of water-soluble vitamins

A
  • some storage of B-6 and B-12
  • other excreted rapidly
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11
Q

Storage of vitamins in the body

A
  • best to meet DRIs daily, but for most vitamins it takes weeks of low intake before symptoms of deficiency develop
  • toxicity possible if too much is consumed
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12
Q

Vitamin A - retinoids

A
  • preformed vitamin - biologically active
  • mostly animal source
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13
Q

Vitamin A - carotenoids

A
  • provitamin A
  • need to be activate in body
  • mostly plant source
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14
Q

Vitamin A in foods

A
  • retinoids are found in liver, fish, fish oils, fortified milk, and eggs
  • Carotenoids are found in dark-green and yellow-orange vegetables and fruits: beta-carotene has greatest amount of provitamin A activity
  • 70% of vitamin A in North American diets comes from animal sources
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15
Q

Absorption, transport, storage, and excretion of Vitamin A

A
  • 90% of vitamin A is found in liver, which stores enough retinyl ester to last several months
  • it is released into bloodstream from the liver as a retinoid bound to retinol-binding protein (RBP) and transthyretin
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16
Q

Functions of vitamin A retinoid

A
  • growth
  • development
  • cell differentiation
  • vision
  • immune function
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17
Q

Vision

A
  • retinal is needed in the retina, as it turns visual light into nerve signals to the brain
  • rods and cones are sensory elements on retina: rods are responsible for translating objects into black-and-white images and detecting motion; cones are responsible for translating objects into color images
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18
Q

Vitamin D

A
  • conditional vitamin
  • prohormone
  • vitamin: precursor from sunlight or diet
  • hormone: activated 1, 25-(OH)2D2 is produced in the body
  • in the gut, activated D switches on genes for proteins that enable calcium absorption
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19
Q

Vitamin A Deficiency Disease

A
  • least common vitamin deficiency along with vitamin E
  • major public health problem in developing countries (leading cause of non-accidental blindess)
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20
Q

Vitamin D3

A
  • produced naturally in skin
  • form of most supplements
  • FYI vitamin D2: derived from ergosterol; plant origin
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21
Q

25-hydroxyvitamin D3

A
  • calcifediol
  • 25-OH added in liver
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22
Q

1, 25-dihydroxyvitamin D3

A
  • calcitriol
  • fully activated form
  • 1-OH added in kidney under control of PTH
  • sometimes abbreviated 1, 25-(OH)2D
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23
Q
A
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24
Q

Functions of Vitamin D

A
  • calcium absorption and maintenance of levels
  • vitamin D may also help regulate immune function, the function of other hormones, cell cycle, cardiovascular and nervous system function
  • this does not mean that supplementation will help any health conditions related to these symptoms
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25
Q

Vitamin D needs

A
  • RDA for most adults is 15 micrograms/600 IU
  • for age 70+ 20 microgram/800 IU
  • breastfed babies should be given vitamin D supplement
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26
Q

Vitamin D deficiency diseases: Rickets

A
  • rickets: abnormal mineralization of bones in children
  • signs include enlarged head, joints, and rib cage, deformed pelvis, bowed legs
  • cab be associated with fat malabsorption, cystic fibrosis, dark skin, low milk intake, minimal sun exposure
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27
Q

Vitamin D deficiency diseases: Osteomalacia

A
  • poor calcification of newly synthesized bone in adults
  • leads to fractures
  • can be seen in adults with: impaired fat absorption, dark skin, limited UV exposure
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28
Q

Vitamin D toxicity

A
  • generally, only seen with excess supplementation
  • upper level is set at 100mg/4000 IU day for 9 and older
  • above this can cause: excess blood calcium, bone loss, calcification in kidneys, heart, and lungs
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29
Q

Should I take vitamin D and/or have my level checked?

A

Routine vitamin D supplementation does not prolong life, decrease the
incidence of cancer or cardiovascular disease, or decrease fracture rates.
Screening asymptomatic individuals for vitamin D deficiency and treating
those considered to be deficient do not reduce the risk of cancer, type 2
diabetes mellitus, or death in community-dwelling adults, or fractures in
persons not at high risk of fractures. Randomized controlled trials of vitamin
D supplementation in the treatment of depression, fatigue, osteoarthritis,
and chronic pain show no benefit, even in persons with low levels at
baseline.” (Am Fam Physician. 2018;97(4):254-260.)

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30
Q

Vitamin E

A
  • family of 8 naturally occurring compounds:
  • tocopherols: alpha, beta, gamma, delta
  • tocotrienols: alpha, beta, gamma, delta
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31
Q

Vitamin E: alpha-tocopherol

A
  • main functions: boosts antioxidant defense, protects cell membranes, enhances immune function
  • daily recommendation: 15 mg
  • good sources: vegetable oil, nuts, avocado
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32
Q

Vitamin E needs

A
  • RDA is set at 15 mg/day alpha-tocopherol: based off prevention of hemolysis during in vitro studies, not based on long term health and disease risk, RDA is based on prevention of deficiency - might be too low
  • average adult consumes 7-8 mg/day (marginal deficiency, symptoms rare)
  • daily value is 30 IU: this system accounts for activity of different forms
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33
Q

Absorption, transport, storage, and excretion of Vitamin E

A
  • absorption by passive diffusion
  • variable: 20-70%
  • travels to liver in chylomicrons
  • liver repackages vitamin E into other lipoproteins for delivery
  • does no accumulate in the liver; 90% is localized to adipose tissue
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34
Q

Functions of vitamin E

A
  • antioxidants, especially in lipid-rich areas
  • research on supplementation has been mixed: overall, supplementation of E beyond the RDA is not recommended, may be harmful in certain situations: increased cancer and bleeding risk
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35
Q

Vitamin E deficiency

A
  • rare but possible in: those with fat malabsorption conditions, smokers, preterm infants
  • characterized by: premature breakdown of red blood cells, which leads to development of hemolytic anemia, impaired immune function, neurological changes in spinal cord and peripheral nervous system
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36
Q

Vitamin K

A
  • assists in blood clotting
  • promotes bone calcification
  • prevents blood vessel calcification
  • Phylloquinones (vitamin K1): from plants, the main biologically active form
  • menaquinones (vitamin K2): fermented foods, bacteria in large intestine
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37
Q

Vitamin K sources

A
  • 10% absorbed daily comes from bacterial synthesis in colon
  • remainder comes from food
  • heat stable
  • most people meet AI
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38
Q

Absorption, transport, storage, and excretion of vitamin K

A
  • 80% if dietary vitamin K is absorbed and incorporated into chylomicrons
  • menaquinones synthesized by bacteria are absorbed by passive diffusion in the large intestine
  • incorporated into lipoproteins for transportation
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39
Q

Functions of Vitamin K

A
  • used for posttranslational modification of proteins: coenzyme for synthesis of Gla domains
  • Key proteins with Gla” prothrombin and other coagulation factors, osteocalcin
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40
Q

Warfarin

A
  • patients should maintain steady intake of Vitamin K
  • Vitamin K can be used to reduce warfarin effects
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41
Q

Vitamin K Deficiency

A
  • can occur in newborns: stores are low and bacteria not yet present in colon, standard practice to give vitamin K injection at birth
  • otherwise rare, but can occur in: prolonged antibiotic used, impaired fat absorption
  • mega-dosesof vitamin A and E negatively affect either absorption or action of vitamin K
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42
Q

Water soluble vitamin overview

A
  • only small amounts are stored in the body: risk of toxicity is low for most, readily removed by the kidneys and excreted in urine
  • most easily destroyed by cooking compared to fat-soluble vitamins: can leech into cooking water, retention is greatest when steaming, stir-frying, and microwaving, thereby limiting exposure to heat and water
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43
Q

B-vitamins function as coenzymes

A
  • small, organic molecules that combine with inactive enzymes to form active enzymes
  • in foods, B-vitamins are present as individual molecules, in coenzyme form, or complexed with proteins
  • digestion frees vitamin molecules from complexes
  • most B-vitamins are contained in the germ and bran of wheat
  • in the US white flour is enriched with 4 B-vitamins and iron: thiamin, riboflavin, niacin, folic acid
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44
Q

Thiamin (vitamin B-1)

A
  • found in small amounts in a wide variety of foods
  • some foods contain antinutrients that lower the bioavailability of thiamin
  • antinutrients are controversial: not linked to deficiency, and may have beneficial effects
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45
Q

Thiamin Needs and Upper level

A
  • most people get enough between natural sources and fortified foods
  • no upper level has been set
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46
Q

Functions of Thiamin

A
  • thiamin pyrophosphate (TPP) is a cofactor in certain decarboxylation reactions
  • pentose phosphate pathway: coenzyme for transketolase
  • needed for normal function of nervous system
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47
Q

Thiamin deficiency Beriberi

A

historically seen in populations where diet consisted primarily of white rice

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48
Q

Dry beriberi

A
  • peripheral neuropathy and weakness
  • muscle pain and tenderness
  • Wernicke-Korsakoff syndrome is a form of dry beriberi associated with alcoholism (psychosis and memory impairment
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49
Q

Wet beriberI

A
  • affects cardiovascular system
  • congestive heart failure
  • edema
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50
Q

Riboflavin (vitamin B-2)

A
  • small amount from a variety of foods, including enriched flour
  • most people get enough
  • no upper level
  • excess goes into urine; causes bright yellow color that glows under black light
51
Q

Functions of Riboflavin

A
  • component of 2 coenzymes of energy metabolism: Flavin mononucleotide (FMN) and Flavin adenine dinucleotide (FAD)
  • formation of other B-vitamins: Niacin from tryptophan and active form of vitamin B-6
  • antioxidant function: required for synthesis of glutathione
52
Q

Riboflavin Deficiency

A
  • ariboflavinosis primarily affects the mouth, skin, and red blood cells
  • symptoms include: inflammation of throat, stomatitis, glossitis, angular cheilitis, seborrheic dermatitis
  • often occurs with deficiency of other B-vitamins
53
Q

Niacin (Vitamin B-3)

A
  • exists in 2 forms: Nicotinic acid and Nicotinamide
  • both forms are used to synthesize niacin coenzymes: Nicotinamide adenine dinucleotide (NAD+) and Nicotinamide adenine dinucleotide phosphate (NADP+)
54
Q

Niacin in foods

A
  • preformed in poultry, meat, fish, enriched bread, mushrooms, and peanuts
  • can be synthesized from tryptophan: Trp makes up about 1% of protein, divide grams protein by 6 to get approximate niacin equivalent
55
Q

Niacin Needs and upper level

A
  • average intake is greater than the RDA
  • upper level about 2x the RDA however, only applies to supplements and fortified foods
56
Q

Absorption, transport, storage, and excretion of Niacin

A
  • free Niacin is readily absorbed from stomach and small intestine by active transport and passive diffusion
  • bioavailability is low in some grans, especially corn (bound to protein)
  • Niacin can be released by soaking in calcium hydroxide (lime water)
57
Q

Functions of Niacin

A
  • coenzymes participate in oxidation-reduction reactions
  • required for metabolism of all energy-yielding nutrients
  • at least 200 different reactions
58
Q

Niacin Deficiency

A
  • the only nutritional deficiency to read epidemic proportions in the US
  • pellagra: symptoms include dermatitis, rough red rash around body, diarrhea, dementia
  • death can occur if untreated
59
Q

Pantothenic Acid (vitamin B-5)

A
  • part of coenzyme A: used throughout the body energy metabolism
  • found in many foods; higher levels in unprocessed
  • isolated deficiency rare to non-existent
  • no observed toxicity
60
Q

Biotin (vitamin B-7)

A
  • coenzyme for several carboxylase enzymes
  • specific example: carboxylation of pyruvate to form oxaloacetate
  • small amounts in a wide variety of foods
61
Q

biotin deficiency

A
  • deficiency extremely rare
  • biotinidase deficiency: genetic mutation with non-functional enzyme and cannot release biotin from food
  • raw egg diet: avidin
62
Q

Vitamin B-6

A
  • family of 3 compounds: pyridoxal, pyridoxine, pyridoxamine
  • primary vitamin B-6 coenzyme is pyridoxal phosphate (PLP)
63
Q

Vitamin B-6 in foods

A
  • sources: meat, fish, poultry, whole grains, some fruits/veg
  • most people are close to the RDA
  • UL is about 50x the RDA: tingling, numbness, higher doses: permanent nerve damage
64
Q

Functions of Vitamin B-6

A
  • coenzyme for 100+ reactions
  • specific examples: amino acid synthesis, glycogen breakdown, hemoglobin synthesis
65
Q

Vitamin B-6 Deficiency

A
  • severe deficiency is rare
  • certain medications can cause low blood levels of B-6: Levodopa and Isoniazid
  • deficiency causes microcytic hypochromic anemia
66
Q

Folate (vitamin B-9)

A
  • folate is a generic term for several naturally occurring derivatives
  • folic acid is a specific form in supplements and fortified foods
67
Q

Folate in food

A
  • major sources: leafy green vegetables and fortified foods
  • mandatory enrichment of grains began in 1998
  • food processing and preparation destroys 50-90%
68
Q

Folate needs

A
  • most people meet RDA
  • however, about 20% of women of childbearing age do not get enough
  • upper level is 2-3x RDA; greater intake masks B-12 deficiency
69
Q

Functions of folate

A
  • coenzyme form is tetrahydrofolic acid
  • functions in reactions where a single carbon is transferred
  • most significant function is in nucleotide synthesis
70
Q

Neural tube defects

A
  • linked to deficiency of folate and enzyme mutations in the folate pathway
  • spina bifida: paralysis, hydrocephalus, learning disabilities
  • anencephaly: lack of brain formation, fatal shortly after birth
71
Q

Vitamin B-12

A
  • cobalamin (most supplements contain cyanocobalamin)
  • only vitamin that contains cobalt, and most chemically complex overall
  • comes from only animal sources
  • stored in large quantities
  • complicated absorption
  • cyanocobalamin form of vitamin B-12 forms 2 active coenzymes: Methylcobalamin and 5-deoxyadenosylcobalamin
72
Q

Vitamin B-12 needs and upper level

A
  • most North Americans eat plenty of animal products and exceed RDA
  • vegans need to supplement
  • body can store 2-3 year supply
  • no upper level is set
73
Q

functions of vitamin B-12

A
  • synthesis of methionine from homocysteine (also regenerates active folate)
  • metabolism of odd-numbered fatty acids
74
Q

Vitamin B-12 deficiency

A
  • inflammation/autoimmune conditions in stomach: Pernicious anemia: anti-intrinsic factor antibodies. H. pylori infection
  • problems with absorption: Crohn’s
  • symptoms: macrocytic anemia, neurological changes and nerve degeneration, elevated plasma homocysteine concentrations, which may increase risk for heart attack and stroke
75
Q

Vitamin C

A
  • ascorbic acid
  • donates electrons in oxidation-reduction reactions
76
Q

Vitamin C in foods

A
  • richest sources are: citrus fruits, peppers, green vegetables
  • 5 servings/day of fruits and vegetables provide enough vitamin C
  • least stable vitamin and easily lost in storage, processing, and cooking
77
Q

Vitamin C needs

A
  • most people get enough but deficiency does exist
  • about 6% have blood levels indicating deficiency
  • smokers need about 33% more vitamin C
  • 200-400 mg/day maximizes plasma level: with greater intake, absorption decreases and excretion increases
78
Q

Upper level and tissue storage

A
  • upper level is 2000 mg/day (compare to RDA of 90 mg)
  • based on adverse gastrointestinal effects: bloating, stomach inflammation, diarrhea
  • high concentrations are stored in: pituitary and adrenal glands, white blood cells, eyes, brain
79
Q

Functions of vitamin C

A
  • antioxidant defense functions
  • regenerates oxidized vitamin E
  • may have a role in aqueous environment similar to vitamin E’s role in lipid rich areas
  • cofactor for several metalloenzymes
  • examples of substances synthesized by vitamin C dependent metalloenzymes: collagen, tyrosine, thyroid hormone, neurotransmitters
  • iron absorption: facilitates absorption of non-heme iron
  • immune functions: white blood cells contain high levels of both reactive oxygen species and vitamin C
  • may protect against self-inflicted damage
80
Q

Vitamin C deficiency

A
  • early symptoms appear after 20-40 days on a vitamin C free diet
  • many symptoms are related to weak collagen: petechiae (pinpoint hemorrhages), bleeding gums, impaired wound healing, bone pain, fractures
  • psychological symptoms
81
Q

Vitamin C, Cancer, and Heart Disease

A
  • no conclusive evidence regarding cancer and heart disease prevention
  • increasing vitamin C intake has small benefit in some studies, no effect in others
  • some studies have shown benefits of vitamin C from dietary sources but not from supplements
82
Q

Vitamin C and colds

A
  • many trials conducted with supplements ranging from 250-2000 mg/day
83
Q

Will supplementation prevent you from getting a cold?

A
  • general population: NO
  • people under intense physical stress (marathon runners and soldiers): Yes, 50% reduction in incidence
84
Q

Will suplementation reduce the duration of a cold

A
  • if started before getting sick, duration is about 1 day shorter
  • if started after getting sick, no effect
85
Q

water

A
  • maintaining the right amount of water in the body is essential to life
  • adults can survive several weeks without food, but only days without water
  • there are no reserves for water in the body, like for the other macronutrients
86
Q

Functions of water

A
  • solvent for all body fluids such as blood saliva, amniotic fluid
  • transports nutrients, oxygen, wastes
  • participates in hydrolysis reactions
  • temperature regulation
87
Q

water needs

A
  • needs vary with body size, physical activity, environmental conditions and dietary intake
  • adequte intake: 15 cups for men (120 oz), 11 cups for women (88 oz)
  • the AI includes water intake from food and metabolism, so you don’t need to drink this much
88
Q

Water input

A
  • fluids (8 cups)
  • water contained in food (2 cups)
  • water produced from metabolism (1.25 cups)
89
Q

Insensible losses

A
  • skin perspiration (3 cups)
  • lung respiration (1.25 cups)
  • feces (0.4 cups)
  • sensible losses: urine (6.75 cups)
90
Q

Notes about fluid intake

A
  • don’t need to worry too much about dehydration with caffeinated beverages
  • alcoholic beverages increase urine output and may lead to dehydration
  • in the U.S. bottled water is no safer than municipal tap water. Some bottled water is simply municipal tap water that has gone through additional purification
91
Q

Dehydration

A
  • can be caused by: medical conditions where water is lost: diarrhea, vomiting, fever, diabetes, burns
  • heavy exercise
  • hot weather, dry environments, high altitudes
92
Q

Overview of minerals - essential, inorganic elements

A

needed in small amounts for function, growth, and maintenance of tissues

93
Q

major minerals

A

need 100 mg or more daily, found in larger quantities in the body

94
Q

trace minerals

A

needed/stored in smaller amounts

95
Q

food sources of minerals

A
  • found in both animal and plant food
  • bioavailability issues: large doses of one mineral may interfere with absorption of another, chemicals in food many decrease absorption
  • quantity of minerals is influenced by agricultural practices and food processing
96
Q

Absorption and bioavailability continued

A
  • regulated by physiological need
  • physiological factors: reduction of iron by HCl or vitamin C, vitamin D increases absorption of calcium, magnesium and phosaphate
  • plant compounds that bind minerals phytic acid, oxalic acid, polyphenols
97
Q

Phytic acid

A
  • wheat grain, legume fiber, and unleavened breads
98
Q

Oxalic acid

A

leafy green plants

99
Q

Polyphenols

A

tea, dark chocolate, and wine

100
Q

transport and storage of minerals

A
  • travel in blood in free form or bound to proteins
  • storage varies: calcium and phosphorus are stored in bones and teeth, iron stored in small amounts in liver and bone marrow, trace mineral storage is very small
101
Q

Sodium

A
  • there are many sources of sodium, even if you never touch a salt shaker
  • processed foods are largest source
  • table salt, NaCl, used for flavor
  • preservatives, leavening agents, anticaking agents are all sodium salts
102
Q

Absorption, transport, storage, and excretion of sodium

A
  • almost all sodium consumed is absorbed by active transport in small and large intestines. Energy for absorption is supplied by sodium-potassium pump
  • in the body, most sodium is dissolved in extracellular fluid
  • excretion: kidneys excrete excess, when Na+ levels and/or blood pressure are low, aldosterone causes sodium retention
103
Q

Functions of sodium

A
  • required for normal nerve and muscle function: establishes membrane potential, moves into excitable cells during action potential
  • helps absorb glucose and some amino acids in small intestine
  • aids in water balance and maintains blood pressure
104
Q

Sodium deficiency

A
  • extremely rare as a dietary deficiency (almost everyone consumes enough)
  • sweat seems salty but is actually hypotonic compared to blood, in other words, you lose water faster than salt when you are sweating
  • vomiting and diarrhea, especially in infants, can cause sodium depletion
  • more common cause of hypoatremia is excess water consumption
105
Q

Excess sodium and upper level

A
  • excess sodium generally gets excreted by the kidneys without serious acute effects: risk factor for cardiovascular disease, certain individuals may be more salt sensitive
  • greater than 2g/day leads to more calcium being excreted in urine, but so far has not been linked to osteoporosis
106
Q

Potassium

A
  • fruits, vegetables are best sources, but small amounts in many foods
  • also supplied by salt substitutes (potassium chloride)
  • potassium needs: adequate intake is 4700 mg/day
  • daily value is 3500mg
  • most people do not get enough
107
Q

Potassium functions

A
  • 95% is found inside cells-major intracellular cation
  • works in many of the same areas as sodium: membrane potential, nerve and muscle function
  • reduces calcium excretion
  • may blunt the effects of high salt intake and help keep blood pressure normal: suppresses renin-angiotensin system and promotes secretion of sodium and water
108
Q

Potassium deficiency

A
  • low blood levels (hypokalemia) can be immediately life-threatening due to arrhythmia
  • may occur with diuretic drugs or eating disorder
  • dietary deficiency generally does not cause hypokalemia but can increase chronic disease risk: stroke, osteoporosis, kidney stones
109
Q

Potassium excess

A
  • hyperkalemia can also cause fatal arrhythmia
  • not observed due to high dietary intake
  • kidney disease, supplement overdoes, potassium sparing diuretics
110
Q

Chloride

A
  • almost all comes from table salt (NaCl)
  • most is found in extracellular fluid
  • helps maintain membrane potentials
  • also component of HCl in stomach
111
Q

Hypertension and Nutrition

A
  • 1 in 3 adults has hypertension
  • most cases are primary (essential) hypertension: develops over several years as a response to changes in the arteries, kidneys, and sodium/potassium balance
112
Q

Calcium

A
  • many adults do not meet RDA
  • groups with higher requirements tend to have lowest intakes
  • bioavailability varies widely - RDA assumes mixed diet and is a target for total calcium, not bioavailable calcium
  • must consider source and overall amount
113
Q

What has more calcium than milk

A
  • Chinese cabbage, mustard greens, turnip greens, brussels sprouts, broccoli, kale, cabbage, cauliflower
114
Q

Calcium supplements

A
  • prefeered to obtain calcium from diet, better absorption, possible increased heart attack risk with supplements (artery calcification)
  • supplements have not been demonstrated to protect against fractures
  • US preventive services task force recommends against supplementation
115
Q

Functions of calcium

A
  • development and maintenance of bones and teeth
  • blood clotting
  • transmission of nerve impulses
  • muscle contraction
  • cell metabolism
  • the body maintains blood calcium concentration within a narrow range
  • when calcium in blood decreases, parathyroid hormone (PTH) is secreted
116
Q

PTH increases: (calcium)

A
  • absorption from gut
  • reabsorption from kidney
  • resorption from bone
117
Q

Bone development and maintenance

A
  • bone consists of protein, (mainly collagen) and minerals (especially calcium and phosphorus)
  • minerals form hydroxyapatite, which binds to collagen
  • enamel and dentin also contain hydroxyapatite
118
Q

osteoporosis prevention

A
  • diets including calcium, vitamin D, magnesium, phosphorus, potassium, vitamin K, and protein
  • weight-bearing activity
  • avoid smoking
119
Q

phosphorus

A
  • found in many foods and food additives
  • deficiency extremely rare
  • toxicity from nutrition extremely rare; hyperphosphatemia occurs due to kidney disease
  • absorption enhanced by vitamin D
  • most of body’s supply is in bone (hydroxyapatite)
120
Q

Phosphorus functions

A
  • phosphates are the main intracellular
  • components of: ATP, creatine phosphate, DNA and RNA, phospholipids, other enzymes and cellular messengers, regulation in ac0d-base balance
121
Q

Magnesium

A
  • leafy green vegetables are good sources since it is a component of chlorophyll
  • unrefined grains, nuts also good
  • average intakes are below RDA
  • about half of body’s supply is stored in bone
122
Q

Magnesium functions

A
  • stabilizes ATP
  • contributes to bone structure and mineralization
  • membrane potential
  • adequate intake may reduce risk of metabolic syndrome, hypertension, cardiovascular disease
123
Q

Sulfur

A
  • a major mineral, provided by sulfur-containing amino acids like methionine and cysteine
    -required for: stabilization of protein structure and detoxification (glutathione)

Nutritional Aspects of Health (4 decks)

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