MIdterm 2 Section 5 Flashcards

1
Q

teratogenic definition

A

toxic side effects

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2
Q

vitamin A deficiencies and toxicity side effects

A

deficiency can lead to blindness, susceptibility to measles
toxicity can cause birth defects

retinal deficiency: night blindness
retinoic acid deficiency: bitot’s spots, xerophthalmia, keratomalacia

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3
Q

vitamin A forms and functions

A

food sources: retinoids (animal) and carotenoids (plant)
converted in the body: retinol (from retinoids) –> retinal –> retinoic acid
supplement sources: retinyl ester

retinol - supports reproduction
retinal - participates in vision
retinoic acid - regulates growth

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4
Q

what role does vitamin A play in sight?

A

within the retinal cells (rods and cones) in the back of the eye
retinal sits in a cis configuration as part of rhodopsin, adjacent to the opsin protein
when a photon hits rhodopsin (low intensity light), retinal changes to trans configuration, sending an electrical impulse to the brain

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5
Q

bitot’s spots

A

lesions that appear in the white of the eye due to retinoic acid deficiency

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6
Q

xerophthalmia

A

dry eyes

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7
Q

keratomalacia

A

Changes structure of surface of eye, causes drying and clouding
Causes irreversible blindness
Due to retinoic acid deficiency

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8
Q

Cataracts

A

Lens becomes less flexible with age (difficulty seeing up close)
Cataracts - lens gets cloudy, surgery vibrate lens to break up lens and take it out, and then replace the lens

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9
Q

Vitamin A role in mucous membrane health

A

Necessary in mucous membrane of GI and lungs
Maintains differentiated goblet cells and columnar cells
Allows pathogens into the body more easily
GI and respiratory illness risk increases

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10
Q

Retinoic acid functions

A

1) cell differentiation: controls gene expression
- goblet/epithelial cells and embryonic growth (deficiency/toxicity)
- membrane integrity, taste, digestion, absorption, malformations in toxicity
2) Immunity: direct and indirect (epithelium)
3) Growth: cell division and bone remodeling

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11
Q

RDA and UL for vitamin A

A

in RE retinol equivalents
500mg RE RDA
15000mg RE UL

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12
Q

Good food sources of vitamin A or beta carotene

A

dark green and deep orange veggies
sweet potatoes, beef liver, dairy is fortified, carrots, broccoli

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13
Q

vitamin K forms and function

A

phylloquinone - plant form
menadione - vitamin form
functions:
- carboxylation of glutamic acid residues in proteins to enable Ca binding (ex. osteocalcin)
- blood clotting cascade

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14
Q

vitamin K deficiency occurs with

A

fat malabsorption, newborns, antibiotic use
contraindicated with anti-clotting drugs

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15
Q

vitamin K in the blood clotting cascade

A

vitamin K helps to form a prothrombin precursor
calcium and thromboplastin activate prothrombin to thrombin active enzyme
fibrinogen and thrombin form a mesh to trap RBC and clot

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16
Q

when taking Warfarin (coumadin)

A

sudden changes in vitamin K can affect medication from working (anti-clotting)
maintain dietary intake of vitamin K from liver, brassica veg and eggs

17
Q

Zinc functions

A

metalloenzyme cofactor: DNA/protein synthesis, release of vitamin A stores, taste perception, free radical protection, heme synthesis, immune function, wound healing, growth/development, pancreatic enzymes for digestion

18
Q

good food sources of zinc

A

oysters, dairy, beef, crab, sunflower butter

19
Q

why is zinc deficiency difficult to diagnose?

A

because the body will pull from stores to supply blood zinc values, so blood tests are not effective
easily misdiagnosed as PEU protein energy malnutrition

20
Q

RDA and UL for zinc

A

don’t supplement
women 8mg/day
men 11mg/day
UL 40mg/day

21
Q

Zinc enteropancreatic pathway

A

Zn2+ once absorbed in SI, Zn is bound to albumin and transferrin
and carried to the liver
bound to albumin Zn continues to pancreas to make digestive enzymes and other metalloenzymes, to be secreted into SI
recycled and cycled backed to intestinal cells
Zinc stored as metallothionein in intestinal cells and liver
Some losses in feces, shed intestinal cells, urine, skin, blood and semen

22
Q

Zinc absorption efficiency

A

33%, increases when deficient
Divalent metal transporter in jejunum same as Ca, Fe, Cu and Pb
absorption enhance and inhibited by same factors as Ca

23
Q

Zinc toxicity symptoms

A

nausea, vomiting, diarrhea
copper deficiency
increased intestinal metallothionein which binds copper and is shed in mucosal cells in feces
can contribute to iron deficiency (DMT competition)

24
Q

Thyroid hormones and functions

A

T3 - triiodothyronine
T4 - thyroxine
Both made from tyrosine amino acid
Functions: metabolic rate of cells, body temp, RBC synthesis, growth, reproduction, brain development

25
Q

Goiter is caused by

A

signaling thyroid to make more hormone but cannot due to iodine deficiency

26
Q

how much iodized salt to meet RDA?

A

2g (average intake is 8g)

27
Q

Normal thyroid pathway

A

Healthy: hypothalamus senses decreased T3/T4
signals pituitary to secrete TSH
TSH signals increased T3/T4 synthesis
levels increase

Deficient: same until TSH signals increased T3/T4 synthesis
no iodine available leads to continued signaling with no effect
leads to goiter

28
Q

Mineral interactions

A

Increased iron occupies transferrin binding sites and decreases Zn transport and absorption

Increased Zn/metallothionein causes Cu to be bound more tightly, and not released from mucosal cells

Decreased protein intake decreases albumin availability, decreased Zn released from mucosal cells (growth failure, immune deficiency)

29
Q

Vitamin C functions

A

Ascorbic acid - antioxidant/reducing agent
collagen synthesis
bone/teeth development
scar tissue, wound healing
hormone synthesis

30
Q

Vitamin C RDA and UL

A

10mg to prevent scurvy
75-90 RDA
2000 UL - mega doses produce Fe Fenton reaction

31
Q

Good sources of vitamin C

A

broccoli, orange, tomato, strawberries, red bell pepper, kiwi brussel sprouts

32
Q

Vitamin E functions and deficiency symptoms

A

Functions: antioxidant, protects PUFAs in membrane lipids, protects lungs, protects lipids in foods
Deficiency symptoms: RBC/WBCs break, cataracts, arthritis, cancer, fibrocystic breast disease, CVD (LDL oxidation)

33
Q

Types of vitamin E

A

Alpha-tocopherol is supplement form
Many isomers (8) of vitamin E tocopherols , Not sure all have the same effect

34
Q

Antioxidants to know

A

Food sources: vitamin C fruits and veg, vitamin E veggie oils, nuts, fruits and veg, B-carotene dark green or orange veg

Metalloenzymes: Se, Mn, Zn, Fe

Glutathione - tripeptide major intracellular antioxidant

Phytochemicals - polyphenols, resveritrol, lutein, zeaxanthin, carotenoids

35
Q

lutein and zeaxanthins

A

protect against cataracts and macular degeneration

36
Q

health effects of higher dose vitamin E, beta-carotene and vitamin A

A

increase risk of mortality

37
Q

Definition of functional foods

A

foods that contain physiologically active compounds that provide health beyond their nutrient contributions
ex. flax, dark chocolate, tomatoes, blueberries, salmon, soybeans