Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

NUTRSCI 332 > EXAM3 > Flashcards

EXAM3 Flashcards

1
Q

One difference between water-soluble vitamins and fat-soluble vitamins is that ____.

A

in large amounts, fat-soluble vitamins can be more toxic than water-soluble vitamins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

B vitamins have a major role in _______.

A

energy metabolism

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What disease can result from prolonged thiamin deficiency?

A

Beriberi

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Of the following foods, which is the best source of riboflavin?

A

Liver

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Which of the following regarding niacin are correct?

A
  • Niacin deficiency can lead to dermatitis.
  • Niacin flush is a parmacological side-effect that occur from taking large dosese of supplemental niacin to improve plasma lipid profile.
  • The RDA for niacin is expressed in milligrams of niacin equivalents.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Which of the followings are correct?

A
  • Vitamin B6 is stored in muscle tissue.
  • Vitamin B6 helps with carbohydrate, fatty acid, and amino acid metabolism.
  • Alcohol contributes to the destruction of vitamin B6 in the body.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Which of the following nutrient deficiencies can lead to megaloblastic anemia.

A

Vitamin B12
Folate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

High intakes of folate can mask a deficiency of which nutrient?

A

Vitamin B12

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Fortification of grain products with folate has helped reduce the prevalence rate of neural tube defects, as well as the prevalence of _______.

A

macrocytic anemia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Which group is at a higher risk of developing vitamin B12 deficiency?

A

Older adults

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Which of the following accurately describes fat-soluble vitamins?

A

Deficiency symptoms sometimes take a long period of time to develop after insufficient dietary intake.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Night Blindness is ______.

A
  • the first sign of vitamin A deficiency
  • the inability to seeing in dim light or darkness
  • due to low levels of retinal in the eyes
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Which food is a rich source of retinoids (e.g. retinol and retinyl ester)?

A

Beef liver

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What happens to an animal raised on retinoic acid as its only source of vitamin A?

A

It becomes blind.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

For a vegan, which of the following represent from dietary intake to storage the forms of vitamin A?

A

provitamin A carotenoids – retinal – retinol –retinyl ester

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

The final step of vitamin D activation – the synthesis of 1,25(OH)2D3 – occurs in the ______.

A

kidney

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Vitamin D deficiency leads to ______ in children and ______ in adults.

A

Rickets, osteomalacia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Vitamin D is critical for bone health, because it promotes ______.

A

calcium and phosphorus absorption

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Which of the following is a naturally occurring food source of vitamin D?

A

Beef
Salmon

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Which of the following features are shared by Vitamin A and D?

A
  • Both can cause toxicity.
  • Both require dietary fat for their absorption.
  • Both can function like a hormone – transformed in the cells into molecules that bind to and activate specific nuclear receptors, exhibit their function, and are subsequently inactivated.
  • Both regulate the expression of genes
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Which of the following are true regarding body electrolytes?

A
  • Sodium is the main extracellular cation
  • Sodium is typically paired with chloride in extracellular fluid
  • Excessive movement of water out of cells causes dehydration
  • Na+/K+ ATPase pumps potassium INTO the cell and sodium OUT to create a gradient.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Fluid movement out of and into capillaries

A
  • Fluid is absorbed into the capillaries on the venous side
  • Is controlled in part by the albumin concentration (large plasma proteins)
  • Fluid filters out of capillaries on the arterial side
  • K+ and Na+ and filtered to maintain osmotic equilibrium
  • Protein pumps requiring energy move ions across membranes to create gradients so that the equilibrium is different in vs out of the cell.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Regarding water consumption

A
  • Increases during prolonged heavy exercise
  • Consume 1 ml of water for every Kcal burned per day
  • Overconsumption may be lethal: Often occurs by eating low fat solid foods
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

During prolonged heavy exercise

A
  • Water is lost mainly through sweat and breathing
  • ADH release is increased
  • Kidneys INCREASE water reabsorption because you need more water. That is also why urine output DECREASES.
  • Transcellular water loss INCREASES because you breathe more and produce more respiration.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Andrea takes a large multivitamin containing 5000 mg of vitamin C. Later in the day, she starts to feel abdominal cramps and is worried that the excess vitamin C is the cause. You tell her that this is blank1 (likely/unlikely) because *blank2 (digestion/excretion/absorption/processing) of vitamin C plateaus after about 500 mg daily intake.

A

blank1: unlikely
blank2: absorption

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Wernicke-Korsakoff Syndrome often manifests in alcoholics because those individuals have (select all that apply):

A

Increased thiamin excretion
Lower intake of vitamin B-1
Lower absorption of thiamin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

The measurement of riboflavin sufficiency status is based on:

A

Reduction of oxidized glutathione
The fact that glutathione reductase uses a bound FAD coenzyme

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

You can synthesize niacin from blank1, although this is much less than 100% efficient and depends on blank2 intake.

A

blank1: tryptophan
blank2: protein

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

Match the vitamin with the best description/feature

A

B1 – transketolase activity
B2 – fluorescent yellow
B3 – Niacin
C – most animals can synthesize but not apes
B5 – Component of acetyl-CoA
B6 – PLP
B7 – induced by egg whites (should read “deficiency induced by egg whites)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

Identify which of the following is true about vitamin B-9:

A

Lowers homocysteine levels
Supplementation can mask other vitamin deficiencies
The polyglutamate form is not what we absorb

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

Megaloblastic anemia can result from blank1 or cobalamin deficiency. In the case of cobalamin deficiency, supplementation with blank2, while curing the anemia, can mask the neurological issues such as blank damage that also result from blank4.

A

blank1: folate, b9, or b-9
blank2: folate, b9, or b-9
blank3: myelin or myelin sheath
blank4: cobalamin, b-12, or b12

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

Select all that are true about fat soluble vitamins.

A

Absorbed with fat
Significant toxicity with high doses

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

Which of these represents the correct pathway from the storage form of Vitamin A to the active form of Vitamin A?

A

B. Retinyl esters > retinol > retinal > 9-cis retinoic acid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

A 40-year-old male came into the ER with a broken hip. Testing shows abnormally low serum calcium but his dietary history indicates adequate dietary calcium intake. As a future RD, how would you treat this patient?

A

Recommend a diet rich in fatty fish, irradiated milk, and fortified cereal
Recommend the patient increase his sun exposure
Prescribe a vitamin D supplement

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

Match the features of vitamin K in numbers 1-3 to the correct explanation in A-G.
1. RDA
2. Drug interaction
3. Storage

A
  1. RDA: Not established. AI value for vitamin K is 120 μg/day
  2. Drug interaction: Anticoagulants
  3. Storage: Minimal
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

Match the terms in numbers 1-4 to the best/correct explanation in A-G.
1. Isotonic saline
2. ECF
3. Interstitial fluid
4. Adipose tissue

A
  1. Isotonic saline: 150 mM NaCl
  2. ECF: 20% of body weight
  3. Interstitial fluid: 25% of body water
  4. Adipose tissue: 20% water
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

Water function

A
  • Polar solvent
  • Carrier
  • Maintains molecular structure
  • Participant in hydrolysis and condensation chemical reactions
  • Solvent
  • Lubricant and cushion
  • Thermoregulation
  • Blood volume maintenance
38
Q

Water intake

A
  • 1 mL water/kcal expended (2000 kcal activity = 2 L water or ~7 cups)
  • Must excrete at least 500 mL of urine to eliminate waste products.
  • Consistently concentrated urine is a risk for kidney stones
39
Q

Osmotic particles

A

solutes: salts, sugars, proteins that cannot cross the membrane

40
Q

Osmotic pressure

A

Pressure necessary to stop the movement of water across semipermeable membrane separating two solutions that differ in their concentrations of osmotic particles

41
Q

Particle concentration

A

Isotonic: [particle]out = [particle]in
* Isotonic – cells remain

Hypotonic: [particle]out < [particle]in
* Hypotonic – cells expand

Hypertonic: [particle]out > [particle]in
* Hypertonic – cells shrink

Raisins in water plump as water moves to higher conc. sugar inside

42
Q

Total number of positive and negative charges in each compartment is the same

A

Sodium and chloride are predominate EC electrolytes
Potassium and phosphate are predominate IC electrolytes

43
Q

Fluid pH buffers

A

Bicarbonate and some proteins are buffers
Affected by:
* Respiration in the lungs (exhalation of CO2)
* Excretion in kidneys (remove or reabsorb bicarbonate)

44
Q

Plasma oncotic pressure

A

based on albumin

45
Q

movement of fluid

A

Arterial side filtration: hydrostatic pressure > oncotic pressure
Venous side reabsorption: hydrostatic pressure < oncotic pressure

46
Q

Insensible water loss

A
  • Skin (not sweating)
  • Respiration
  • Only the kidneys can compensate for these losses
47
Q

GI tract

A
  • Saliva, gastric secretions, bile, pancreatic juices, and intestinal secretions contribute another 7000 mL
  • You reabsorb most of this, roughly 8900 mL
  • 100 mL is excreted in feces
48
Q

Dehydration

A
  • Sensation of thirst: excessive loss of body water leads to increase in ECF osmolality (hyperosmolality).
  • Increases as small as 2-3% will activate neural centers in the hypothalamus to produce a strong desire to drink
  • Some individuals are impaired in this response (infants, elderly, some disease states, vigorous exercise)
49
Q

Hypo-osmolarity: Water intoxication

A
  • Occurs following a rapid fall in osmolarity. Water from ECF moves into cells
  • Brain cells swell causing nausea, malaise, headache, confusion, seizures, and coma
50
Q

Kidney functions

A
  • Regulate body fluid osmolarity and volume
  • Regulate electrolyte balance
  • Regulate acid/base balance
  • Excrete metabolic waste products
  • Produce and secrete hormones
51
Q

Nephron

A

Functional unit of the kidney
Tubular system involved in urine production

52
Q

Glomerulus

A

Part of the nephron
Rich in capillaries
Site of plasma filtration into the renal tubes

53
Q

Tubules

A

Site of processing of the plasma filtrate to create urine

54
Q

Filtration

A

Initial removal of water and solutes from the blood. Does NOT include large proteins or blood cells. Solutes in the filtrate include some vitamins, minerals, nutrients

55
Q

Reabsorption

A

Selective removal of water and solutes from the glomerular filtrate back into the blood
Often regulated by hormones (Ca2+ and PTH)

56
Q

PTH and calcium

A

Discussed previously with regards to vitamin D
PTH induces the kidney to activate more vitamin D
Also increases calcium reabsorption and lowers calcium excretion

57
Q

Secretion

A

Selective removal of certain solutes from the plasma into the tubules. Occurs after the blood has passed through the glomerulus

58
Q

Extracellular fluid (ECF)

A

Outside of cells
Intravascular fluid (blood plasma)
Interstitial fluid (around cells)

59
Q

Water percentages

A

Total water is roughly 60% of body weight for lean individuals: 42 L/70 kg body weight
ECF – 20% (14 L)
Interstitial is 75% of ECF (10.5 L)
Plasma is 25% of ECF (3.5 L)
ICF – 40% (28 L)
Adipose: 20%
Skeletal muscle: 70%

60
Q

Sodium (Na+) Function

Major ECF cation

A
  • Critically important for regulating body water and electrolyte balance.
  • Aids in nutrient absorption
  • Very important for neural and muscular function
  • Efficiently absorbed throughout the entire small intestine and colon
  • Plasma Na+ levels are closely regulated by the kidney (intake = output).
  • Excess amounts filtered and excreted.
  • Tubules regulate reabsorption to precisely maintain 145 mEq/L
61
Q

Sodium requirements

A
  • No RDA or RDI
  • Minimum: 500 mg/day adults
  • Depending on physical activity and climate, it is suggested to consume ~3,000 mg/day
  • DRV is < 2,400 mg
  • Average intake in US = 3,000-6,000 mg/day

Processed food contains high amount

62
Q

Sodium sensitivity

A
  • Associated with chronic renal disease, diabetes, hypertension
  • African Americans over 50 years old are prone
  • Individuals with hypertension can lower their blood pressure with restricted sodium intake
63
Q

Sodium deficiency

A

May occur with vomiting, diarrhea, or heavy sweating.
Also muscle cramps, mental apathy, loss of appetite

64
Q

Sodium toxicity

A

Acute toxicity causes edema and hypertension

65
Q

Potassium (K+) Function

Principle cation inside cells

A
  • Plays major role in fluid and electrolyte balance
  • Extremely important in nerve and muscle function, as well as fundamental cell processes and growth
  • Efficiently absorbed (> 90%) in small and large intestine
  • Renal excretion is closely matched to intake
  • Hormonal regulation
66
Q

Potassium dietary requirements

A

No RDA or RDI
Estimated minimum requirement in adults = 2000 mg/day
DRV = 3500 mg/day

67
Q

Potassium deficiency

A
  • Low blood K+ is termed Hypokalemia (< 3.5 mEq/L). Mostly occurs b/c of diarrhea, vomiting, and severe dehydration.
  • Also associated with use of certain diuretics, steroids, or abuse of laxatives
  • Causes muscle weakness, paralysis, and confusion, cardiac arrhythmias
  • Low K+ diets may also cause hypertension
68
Q

Potassium toxicity

A
  • Hyperkalemia (≥ 5 mEq/L)
  • Mostly from overuse of potassium supplements
  • Hard to induce from diet as kidney will accelerate excretion of excess from dietary intake
  • Results in muscle weakness, vomiting, and heart failure in severe cases
69
Q

Antidiuretic hormone (ADH)

A
  • Arginine vasopressin
  • Released by pituitary in response to increases in ECF osmolarity or decreased blood volume
  • Predominantly acts on kidneys to increase water reabsorption
  • Alcohol inhibits ADH secession and causes dehydration
70
Q

Renin

A
  • Enzyme released from kidneys in response to decreased blood pressure.
  • Acts in blood on angiotensinogen to produce angiotensin I
  • Angiotensinogen is made in liver
71
Q

Angiotensin I

A

Is converted to angiotensin II in the lungs

72
Q

Angiotensin II

A
  • Most powerful vasoconstrictor in the body.
  • Constricts blood vessels to increase blood pressure.
  • Increases vasopressin production
  • Also causes release of the hormone aldosterone from adrenal glands
73
Q

Aldosterone

A
  • Acts on renal tubules to increase Na+ reabsorption and K+ excretion.
  • Water follows the Na+ and blood volume is increased.
  • Net effect is increase in blood pressure and conservation of water
74
Q

ACE inhibitors

A
  • Angiotensin-converting-enzyme inhibitors
  • Treat high blood pressure
  • Inhibit ACE enzymes that convert Angiotensin I to Angiotensin II
  • Also inhibit the hydrolysis of bradykinin, which is a vasodilator
  • Net effect: lower blood pressure
  • Side effects: cough and angioedema
75
Q

Ascorbic Acid: Vit C

A
  • Antioxidant
  • Collagen (hydroxy amino acid) and NT (carnitine, serotonin, and norepinephrine) syntheis
  • Active transport via SVCT1 and SVCT2
  • Brush border enzymes
  • Water soluble so travels directly into blood
  • Filtered by kidneys and removed in urin
  • Blood vessel integrity and internal bleeding
  • Scurvy Symptoms: pinpoint hemorrhages, joint pain, poor wound healing, inflamed gums
  • Citrus, potato, tomato
  • Minimum: 10 mg
  • Men:90 mg/day
  • Women: 75 mg/day
  • Smokers: +35 mg/day
  • UL: 2000 mg/day
  • Absorption plateau after 500 mg so no abdominal cramp, nausea, and diarrhea symptoms unless chronically exceeded
76
Q

Thiamin: B-1

A
  • TPP (hydroxyl phosphorylated)
  • TPP coenzyme in decarboxylation
  • Pyruvate dehydrogenase
  • Secarboxylation of alpha-keto acids
  • Transketolase activity- testing
  • NT synthesis
  • Storage in liver
  • Active with specific transporters or simple sometimes
  • Through blood bound to alvumin
  • Excreted in urine
  • Infucient food intake or empty calories
  • Malnourished and homeless susceptible
  • Beriberi
  • Wet- cardiovascular
  • Dry- NS
  • Wenicke-Korsakoff in alcoholics
  • Ataxia and nystagmus
  • Pork, wheat
  • Men: 1.2 mg/day
  • Women: 1.1 mg/day
  • No UL
77
Q

Riboflavin: B-2

A
  • Component of FMN (ETC) and FAD (FA beta-oxidation, tryptophan to niacin) coenzymes
  • Between oxidized and reduced
  • Sufficiency based on” Oxidized glutathion reduction
  • Glutathione reductase uses bound FAD
  • In small intestine with active and passive
  • Circulation in blood
  • Storage in riboflavin converted to FMN/FAD
  • Excess excreted via kidnet/ urine
  • B vitamins can turn urine bright yellow
  • Ariboflavinosis symptoms: glossitis, stomatitis, cheilosis
  • Interaction with phenobarbital
  • Dairy products, animal liver, fortified foods
  • Sensitive to UV
  • Men: 1.3 mg/day
  • Women: 1.1 mg/day
  • Pregnant: +0.5 mg/day
  • No UL established
78
Q

Niacin: B-3

A
  • NAD, NADP
  • Facilitated or passive
  • Synthesize from tryptophan
  • Liver convert excess plasma nicotinamide to NAD storage
  • Excreted in urine
  • Pellagra
  • 4Ds: dementia, diarrhea, dermatitis, death
  • Meat, high protein, fortified foods
  • Men: 16 NE/day or 1.2 mg/day
  • Women: 14 NE/day or 1.1 mg/day
  • 25 mg/day
  • Niacin flush, Cholesterol effects, Liver damage
79
Q

Pantothenic Acid: B-5

A
  • ACP, Acetyl-CoA, 4’phosphopantatheine
  • In small intestine
  • Circulation in blood
  • Most pantothenic acid in CoA form
  • Excess via kidneys/ urine
  • Very rare
  • General system failure
  • Burning feet, BC increase requirement
  • AI adults: 5 mg/day
  • No UL established
  • Possible diarrhea from 10-20 g/day of calcium D-pantothenate
80
Q

Pyridoxine: B-6

A
  • PLP for hemoglobin & AA biosynthesis
  • SI passive diffusion, dephosphorylated for absorption
  • Liver processes vitamin to PLP. sent via blood from liver bound to albumin
  • Liver storage (limited by protein binding) and muscle
  • Excreted via kidneys/urine as 4-pyridoxic acid
  • Uncommmon except in alcoholics
  • Microcytic hypochromic anemia,
  • Drug interaction: L-DOPA (Parkinson’s) and Isoniazid (tuberculosis)
  • Meat, fish, potatoes, veggies (less bioavailable), heat labile
  • Adults: 1.3 mg/day
  • Over 50 men:1.7 mg/day
  • Over 50 women: 1.5 mg/day
  • 100 mg/day
  • Toxicity causes peripheral neuropathy with >2 g/day for 2 months
81
Q

Biotin: B-7

A
  • Acetyl-coA, Cofactor in metabolic rxns and utilization of fats, carbs, or AA. Avidin from egg protein binds to biotin
  • Facilitated transport
  • Must be released from peptides by brush border biotinidase
  • LA may synthesize
  • Travels through blood
  • Storage in liver
  • Excreted in urine
  • Neurological, hair loss, skin rash
  • From diet of raw egg whites
  • Genetic biotinidase deficiency is recessive
  • Many foods, produced by gut bacteria
  • AI adults: 30 µg/day
  • No UL established & toxicity rare
82
Q

Folate: B-9

A
  • THFA
  • Move single carbons in DNA synthesis and repair
  • Useful for methotrexate chemo agent (folate antagonist)
  • Lower homocysteine levels to prevent cardio disease
  • SI absorption of monoglutamate form
  • Active and passive (at high conc.)
  • Needs transport across membranes
  • Enterohypatic circulation
  • Liver processes monoglutamate to polyglutamate
  • Some storage in liver
  • Excrete small amount via urine
  • Alcoholic, pregnancy, B-12 deficiency, diarrhea cause megaloblastic (macrocytic) anemia
  • Decreased DNA synthesis in bone marrow progenitor cells
  • Neural tube defects in fetus days 21-28, anencephaly, hydrocephalus
  • Green leafy veggies, Heat, light, and air sensitive
  • Adults: 400 µg/day
  • 1 mg/day
  • Masks B-12 deficiency
83
Q

Cobalamins: B-12

A
  • Coenzyme for methionine synthase, interaction with folate, myelin sheath
  • R-protein (Haprocorrin) from salivary glands protects from stomach acid.
  • Stomach acid releases proteins bound to B-12.
  • Intrinsic factor from stomach.
  • R-protein degraded in SI. Intrinsic factor then binds to B-12.
  • Absorbed in ileum.
  • Transcobalamin II is epithelial protein that binds to B-12
  • Travels to liver, bone marrow, RBCs
  • Enterohepatic circulation. Excreted by bile.
  • Some liver storage
  • Typically from impaired absorption. R-protein or intrinsic factor defects. Heartburn/ GERD/ ulcer/ GI sx treatment
  • Pernicious megaloblastic anemia.
  • Neuro symptoms: ataxia cognition impaired/ peripheral neuropathy, myelin problems
  • Meat, dairy, fortified food
  • Made by bacteria and archaea
  • 2.4 µg/day
  • No UL established
84
Q

Retinoids: Vitamin A

A
  • Light absorbing pigment in eye (rhodopsin= 11-cis retinal + opsin)
  • Rod cell low light.
  • Visual cycle:
  • Photobleaching results in opsin (vision) and all-trans retinal (for regeneration).
  • Retinoic acid: Nuclear receptor to regulate gene expression via RAR and RXR (form dimers with eachother or Vit D receptor). Made where its used
  • Carotenoids (pro vit. A):
  • BCO1 enzyme for conversion of beta-carotene to retinol. Less likely for toxicity because inefficient.
  • Retinyl esters: SI with bile acids. Desterified like TGs
  • Retinol and beta-carotene metabolized in enterocytes before entering blood. Reesterified and packed in chylomicrons to transport to liver. Retinol binding protein (from liver) carries retinol in blood plasma (holo-RBP)
  • Retinyl esters (from chylomicron remnants) stored in hepatic stellate cells
  • Retinal to retinoic acid is irreversible
  • Excretion via bile and feces
  • Developing countries. Night blindness: can’t regenerate rhodopson and xerothalmia which can cause blindness
  • Animal products (retinyl esters), polar bear liver, dairy, egg, fish, fortified food (margarine, cereal).
  • Pro-vitamin:Caretenoids
  • Beta-caratine (sweet potato, carrot)
  • Men: 900 µg/day RAE
  • Women: 700 µg/day
  • Pregnant: 770 µg/day
  • Lactating 1300 µg/day
  • 3000 µg/day RAE
  • Acute:nausea, vomiting, headache, double vision
  • Chronic: acutane birth defects, anorexia, hair loss, bone fractures, liver damage
85
Q

Alpha-tocopherol: Vitamin E

A
  • Antioxidant
  • Emulsification with bile acids
  • Incorporated into chylomicrons for circulation
  • Processed in liver with alpha-tocopherol transfer protein
  • Excretion via bile and feces
  • Insufficient fat absorption cause. Membrane integrity challenged.
  • Symptoms: retinopathy, peripheral neuropathy, ataxia, lower immunity
  • Vegetable oils
  • Destroyed by heat and oxidation
  • 15 mg/day
  • Alpha-tocopherol form only
  • 1000 mg/day
86
Q

Quinone derivative: Vitamin K

A
  • Blood clotting, activate clotting proteins, bone calcification. Gamma-carboxylation: Thrombin clotting requires
  • SI with fatt/ bile and pancreatic factors
  • Supplements more bioavailable than foods
  • Transport in chylomicrons
  • Limited storage
  • Reducing power of NAD(P)H to recycle vit K
  • Urine or stool
  • Drug interaction with Warfarin blood thinner: drug interferes with vit K recycling, decreasing availability and gamma-carboxylation of clotting factors.
  • Secondary deficiencies from malabsorption or anticoagulant drugs. Nowborns get vit K shot against hemmorages
  • Gut bacteria synthesize,
  • Green leafy vegetables. Vit K is e- acceptor in photosynthesis
  • AI: 120 µg/day men, 90 µg/day
  • For women
  • UL not established
87
Q

Calciferol: Vitamin D

A
  • Serum calcium and phosphorus.
  • Low Ca: PTH released from parathyroid gland which activates kidney enzymes to convert inactive form to active calcitriol which increases Ca absorption from intestine and rebsoption from kidneys
  • High Ca: Calcitonin released from thyroid to stimulate Ca and phosphorus to build (mineralize) bone
  • Bone health: calcitriol facilitates gut absorption. Increases calbindin expression and Ca channels. Similar effects on renal tubules to increase Ca reabsoption from urine.
  • Regulates gene expression by binding VDR and interaction with nuclear receptor and dimerization
  • Immune: cathelicidin anti-microbial peptide
  • Skin synthesis
  • Distal ileum of SI
  • Requires bile acids/fat
  • Incorporated into mixed micelles
  • Packed into chylomicrons for
  • Later circulates bound to vit D binding protein
  • Sun Cholecalciferol (D-3 not active) enters blood bound to vit D binding protein
  • Active form calcitriol from CYP2R1 in liver and CYP27B1 in kidney. Negative feedback
  • Bile to feces, very little in urine
  • Osteomalacia (soft bones) from metabolism diseases
  • Rickets: bow legs, enlarged head and rib cage, deformed pelvis
  • Sun exposure, liver, beef, veal, eggs, saltwater fish, fortified milk/oj
  • 600 IU/day (15 µg)
  • Same for pregnant and lactating women
  • Prevent deficiency (<20 ng.mL 25-OH,D)
  • Elderly: 800 IU/day (20 µg)
  • 4000 IU/day
  • Toxicity from supplementation:
  • Hypercalcemia, kidney dysfunction, GI distress, loss of appetite
88
Q

Criteria for essentiality

A
  1. Deficiency
  2. Specific function
  3. Component of another compound essential in the diet (niacin)
89
Q

Vitamin characterization

A
  • Structure/function
  • Absorption
  • Transport
  • Storage
  • Excretion
  • Dietary recommendations
  • Deficiencies
  • Food sources
90
Q

B vitamins

A
  • Participate in energy metabolism
  • Like vitamin C, water soluble
  • Transport, storage and excretion will be similar
  • Absorbed in the small intestine
  • Sometimes passive, but most often facilitated or active transport
91
Q

lipid-soluble vitamins

A
  • Lipid soluble
  • Absorbed in the presence of fat
  • Absorption/transport is similar to that of fat
  • Can be stored (liver, adipose mostly)
  • Can be toxic in high doses

NUTRSCI 332 (4 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions