Vitamin Flashcards
What are the lipid soluble vitamins? Is toxicity or deficiency more of the problem?
A, D, E, K; toxicity more of a problem since they are more easily stored
What are the water soluble vitamins? Is toxicity or deficiency more of the problem?
B, C; deficiency since they are more easily excreted in urine
What functions is Vitamin A involved in?
Visual cycle with rhodopsin and cone opsins; synthesizing glycoproteins and mucosaccs; retinoic acid as a hormone; antioxidant
What are Vitamin A deficiencies?
Night blindness, xerophthalmia later; follicular hyperkeratosis (like goosebumps); anemia; poor growth in kids; increased vulternability to infection and cancer
Who is susceptible to Vit A deficiencies?
Poor, malnourished, premature babies
What is the order of retinoic acid formation from beta carotene?
Beta carotene –> all-trans retinol –> all trans retinal –> retinoic acid (hormone) –>gene transcription
What are the functions of Vit D?
Maintaining bone and calcium homeostasis; could have wide range of activity, but definitely acts as hormone
What are Vit D deficiencies?
Rickets in kids; osteomalacia in adults; increased vulnerability to cancers like breast, metabolic syndromes, infections
Who’s susceptible to Vit D?
Poor, elderly, alcholics; other groups with mild deficiencies
Although toxicity is rare, what does excess Vit D lead to?
High serum levels of calcium and bone loss
What is thought to contribute to correlation between Vit D levels and cancer risk?
The vitamin D receptor
What is the function of Vit K? What does it catalyze?
Localizing of the enzymes required for clotting; it catalyzes addition of gamma-carboxyglutamate to clotting enzymes
What are Vit K deficiency consequences?
Easy bruising, bleeding, hemorrhage
Who is susceptible to Vit K def?
Newborn infants (lacking klebsiella); long-term antibiotics and patients; elderly or those with defects in fat absorption
What structure does Vit K have?
Quinone ring
How does warfarin act as an anticoagulant?
It inhibits Vit K’s activities
What does Vit E do?
Serves as an ANTIOXIDANT to scavenge free rads; protect membranes from damage and prevent oxidation of LDL (foam cells potentially)
If you had a Vit E deficiency what would you see?
Cardiovascular disease, neurological symptoms (Vit E can be in the myelin sheath)
Who is susceptible to Vit E deficiency?
Patients with severe prolonged defects in absorption (e.g. celiac disease) or genetic defects
What is Vit C responsible for?
Cofactor for oxidases involved in collagen formation; needed for steroid synthesis in stress response; aids in iron absorption; antioxidant
What do you see with Vit C deficiencies (mild and severe)?
Bruising, immunocompromised; severe is scurvy (decreased wound healing, osteoporosis, hemorrhage, anemia, fatigue, corkscrew hairs, pinpoint hemorrhages);
Who is susceptible to Vit C deficiencies?
People with poor diet, smokers
What specific reactions is Vit C involved in?
Prolyl and lysyl hydroxylases for collagen biosynthesis; also epi synthesis
What are the B-complex vitamins?
Thiamine (B1), Riboflavin (B2), Niacin (B3), Biotin, Pantothenic acid (B5), Pyridoxine (B6); Folate (B9) and Cobalamin (B12)
What are common effects of deficiency of energy-releaseing B vits?
Dermatitis, glossitis, diarrhea; nervous system affected, peripheral neuropathy, depression/confusion, lack of coordination, malaise
What is the function of B1?
Required cofactor for several enzymes; critical in nervous system
Deficiencies of B1?
Mild: GI; depression, fatigue (poor, elderly); Moderate: Wernicke-Korsakoff syndrome (alcoholics); Severe: Beriberi (people dependent on polished rice, perhaps alcoholics)
What do you see in Wernicke-Korsakoff?
Mental disturbance, unsteady gait, uncoordinated eye movements; perhaps CHF
What is beriberi characterized by? What is the difference between dry and wet?
Extreme muscle weakness, poly-neuropathy, heart failure; in wet beriberi, we see edema
What is riboflavin a precursor to?
FAD and FMN
What does a B2 deficiency lead to?
Ariboflavinosis: rash around nose, inflammation of mouth and tongue, burning and itchy eyes, light sensitivity (uncommon)
Susceptible groups for B2 deficiency?
Alcoholics (deficiency uncommon)
What is niacin a precursor to? Who could you give it to?
NAD and NADP; hypercholesterolemia or hypertriglyceridemia patients
What can cause biotin deficiency?
Eating a lot of raw eggs
What is pantothenic acid (vit B5) required for?
CoA synthesis
What is pyridoxine a precursor to? What else is it required for?
PLP; required for glycogen breakdown and GABA and heme synthesis
What are deficiencies characterized by (mild and severe)
Mild: irritability, nervousness, depression; Severe: pripheral neuropathy, convulsions, decreased glucose tolerance, hyperhomocysteinemia, anemia
Who’s susceptible to deficiency?
Patients treated with certain drugs, like the TB drug isoniazid
