Nutrition: Fat Solubles, Vitamins, Minerals & Electrolytes - Skildum Flashcards
Which cofactors are used by pyruvate dehydrogenase?
TPP
NAD
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.
RDA: Recommended Daily Allowance.
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.
EAR: Estimated Average Requirement.
What vitamins are fat soluble?
ADEK
The biologically active form of Vitamin A is what?
all-trans-retinol.
The main dietary forms of Vitamin A are [ ] and [ ].
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.
What vitamin A derivative is soluble enough to be transported in the blood associated with albumin? Which is transported in chylomicrons.
Retinoic acid is soluble enough to be transported in the blood associated with albumin. Retinyl-fatty acid esters are transported in chylomicrons.
Stellate cells in the liver serve as the reservoir for what?
Stellate cells in the liver serve as the reservoir for Vitamin A storage.
How does retinyl esters go in and out of hepatocytes?
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)
What are substrates and products of light with respect to vitamin A?
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.
(T/F) Retinoic acid does not act as a transcriptional regulator.
False. It does act as a transcriptional regulator.
What are the transcriptional effects of retinoic acid?
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
Patient presents with alopecia, night blindness and anorexia, what are some other expected symptoms?
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
You treat a patient deficient in vitamin A, but give too much. What would you see?
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
A patient is deficiency in vitamin E. What would you tell them to eat?
Vitamin E is abundant in plant oils, e.g. palm oil, sunflower oil, canola oil, wheat germ.
How are tocopherols and tocotrienol-acyl esters metaboliszed? (Vitamin E)(
Cute by pancreatic lipase, moved to intestinal epithelial cell –> chylomicrons –> liver –> VLDL
It parallels fat dige
(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.
True
What is Vitamin E’s connection to vitamin C and K?
Vitamin E, when oxidized, can be regenerated by ascorbate (vitamin C).
Vitamin E inhibits Vitamin K absorption and metabolism.
Patient presents with myopathy, hemolytic anemia, peripheral neuropathy, ataxia, and loss of vibratory sense. What vitamin deficiency do they have?
Vitamin E
What foods contain vitamin D?
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.
Vitamin D can be synthesized de novo from what?
Vitamin D can be synthesized de novo from cholesterol. To make the active Vitamin D3, metabolism of skin, liver, and kidney is required.
PTH 1 - alpha-hydroxylase acts on this form of vitamind D, the most abundant form in the blood.
25-hydroxycholecalciferol (25-OH D3)
Dietary sources of calcium?
Dietary sources: Dairy, seafood, turnip, broccoli, kale, dietary supplements
What are four effects of the calcium calmodulin
- Activates calcineurin which blocks Ca channels
- Activates MLCK which contracts muscles
- Activates calmodulin kinase which blocks glyogen synth.
- Activates phosphorylase kinase –> phosphorylase
Does calcium block phosphate uptake?
Does it block iron uptake?
What are its effects on bile salts?
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
How is Mg(2+) transported across the basolateral border?
Basolateral transport:
2Na+/Mg2+ antiporter
2K+/3Na+/ATPase
With respect to bicarb, when and where does Cl enter and leave the RBC?
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.
Phosphorous absorption is inhibited by:
Magnesium ( Mg3(PO4)2 is un-absorbable.)
Aluminum
Calcium
(Found in antacids)
Role in phosphorous and bone?
Calcitonin
Calcitriol
Calcitonin: phosphorous deposition in bone
Calcitriol: phosphorous desorption from bone
