Nutrition: Fat Solubles, Vitamins, Minerals & Electrolytes - Skildum

Question 1

Which cofactors are used by pyruvate dehydrogenase?

Answer 1

TPP

NAD

Question 2

The term for average daily dietary nutrient intake level sufficient to meet the nutritional requirements of nearly all (97-98%) healthy persons in a particular life stage and gender group.

Answer 2

RDA: Recommended Daily Allowance.

Question 3

The term for average daily nutrient intake level estimated to meet the requirements of half of the healthy members of a particular life stage and gender group.

Answer 3

EAR: Estimated Average Requirement.

Question 4

What vitamins are fat soluble?

Answer 4

ADEK

Question 5

The biologically active form of Vitamin A is what?

Answer 5

all-trans-retinol.

Question 6

The main dietary forms of Vitamin A are [ ] and [ ].

Answer 6

The main dietary forms of Vitamin A are retinyl-acyl esters and carotenes. They all can be converted to all-trans-retinol.

Associated with orange and red color found in fruits and veggies.

Question 7

What vitamin A derivative is soluble enough to be transported in the blood associated with albumin? Which is transported in chylomicrons.

Answer 7

Retinoic acid is soluble enough to be transported in the blood associated with albumin. Retinyl-fatty acid esters are transported in chylomicrons.

Question 8

Stellate cells in the liver serve as the reservoir for what?

Answer 8

Stellate cells in the liver serve as the reservoir for Vitamin A storage.

Question 9

How does retinyl esters go in and out of hepatocytes?

Answer 9

Hepatocytes mediate retinol homeostasis in the body.
Retinyl esters go in. Sources:
Dietary: Chylomicrons
Stored: Stellate cells

Retinyl esters go out to. . .
Stellate cells (storage)
VLDL (to tissues)

Question 10

What are substrates and products of light with respect to vitamin A?

Answer 10

Cis-retinal bound to the protein opsin is the photoreceptor rhodopsin. Light causes conversion to trans-retinal. Rhodopsin bound to trans-retinal activates a heterotrimeric G protein, closure of a Na+ channel, hyperpolarization of the rod cell, and signaling to the neuron.

Question 11

(T/F) Retinoic acid does not act as a transcriptional regulator.

Answer 11

False. It does act as a transcriptional regulator.

Question 12

What are the transcriptional effects of retinoic acid?

Answer 12

Ligand for RAR and PPAR receptors.
Differentiation of goblet cells
Downregulates keratinization
Apoptosis of cancer cells
Maturation of dendritic cells (better immune antigen presentation)
Recruitment of Ab secreting cells to small

Question 13

Patient presents with alopecia, night blindness and anorexia, what are some other expected symptoms?

Answer 13

The patient has vitamin A deficiency, you'd see:
anorexia
retarded growth
increased susceptibility to infections
alopecia
keratinization of epithelial cells
eyes:  
night blindness
xeropthalmia (dry eye due to keratinization) 
Bitot’s spots

Question 14

You treat a patient deficient in vitamin A, but give too much. What would you see?

Answer 14

Doses in vast excess of this can cause. . .
nausea/vomiting
blurred vision, headache
desquamation of skin
alopecia
ataxia
liver damage (from excess stellate cell growth and proliferation)
conjunctivitis, eye pain

Vitamin A can be a teratogen in very high doses.
Acne medication Accutane

Question 15

A patient is deficiency in vitamin E. What would you tell them to eat?

Answer 15

Vitamin E is abundant in plant oils, e.g. palm oil, sunflower oil, canola oil, wheat germ.

Question 16

How are tocopherols and tocotrienol-acyl esters metaboliszed? (Vitamin E)(

Answer 16

Cute by pancreatic lipase, moved to intestinal epithelial cell –> chylomicrons –> liver –> VLDL

It parallels fat dige

Question 17

(T/F) Vitamin E functions in lipid bilayers in intracellular and plasma membranes. The phenolic hydroxyl can distribute and stabilize singlet oxygen and free radicals as part of cellular oxidative stress defense.

Answer 17

True

Question 18

What is Vitamin E’s connection to vitamin C and K?

Answer 18

Vitamin E, when oxidized, can be regenerated by ascorbate (vitamin C).

Vitamin E inhibits Vitamin K absorption and metabolism.

Question 19

Patient presents with myopathy, hemolytic anemia, peripheral neuropathy, ataxia, and loss of vibratory sense. What vitamin deficiency do they have?

Answer 19

Vitamin E

Question 20

What foods contain vitamin D?

Answer 20

Vitamin D is found primarily in food of animal origin such as liver, eggs, fatty fish. It is also present in shitake mushrooms, and is fortified in many dairy products.

Question 21

Vitamin D can be synthesized de novo from what?

Answer 21

Vitamin D can be synthesized de novo from cholesterol. To make the active Vitamin D3, metabolism of skin, liver, and kidney is required.

Question 22

PTH 1 - alpha-hydroxylase acts on this form of vitamind D, the most abundant form in the blood.

Answer 22

25-hydroxycholecalciferol (25-OH D3)

Question 23

Dietary sources of calcium?

Answer 23

Dietary sources: Dairy, seafood, turnip, broccoli, kale, dietary supplements

Question 24

What are four effects of the calcium calmodulin

Answer 24

1. Activates calcineurin which blocks Ca channels
2. Activates MLCK which contracts muscles
3. Activates calmodulin kinase which blocks glyogen synth.
4. Activates phosphorylase kinase –> phosphorylase

Question 25

Does calcium block phosphate uptake?

Does it block iron uptake?

What are its effects on bile salts?

Answer 25

Calcium blocks phosphorous uptake
High doses of Ca2+ used to treat hyperphosphatemia secondary to kidney failure.

Calcium transiently blocks iron uptake

Calcium can trap fatty acids and bile salts in ‘soaps’ that are not digestable.
Bile salts are not recycycled
Cholesterol is diverted to bile acid synthesis
decreased chenodeoxycholate in bile
LDL decreases

Question 26

How is Mg(2+) transported across the basolateral border?

Answer 26

Basolateral transport:
2Na+/Mg2+ antiporter
2K+/3Na+/ATPase

Question 27

With respect to bicarb, when and where does Cl enter and leave the RBC?

Answer 27

Chloride enters red blood cells in exchange for bicarbonate when cells deliver oxygen to tissues.

Chloride leaves red blood cells in exchange for bicarbonate when cells take in oxygen from lungs.

Question 28

Phosphorous absorption is inhibited by:

Answer 28

Magnesium ( Mg3(PO4)2 is un-absorbable.)

Aluminum

Calcium

(Found in antacids)

Question 29

Role in phosphorous and bone?
Calcitonin
Calcitriol

Answer 29

Calcitonin: phosphorous deposition in bone
Calcitriol: phosphorous desorption from bone