Vitamins Flashcards
List the fat soluble vitamins
DAKE
List the water soluble vitamins
B(1, 2, 3, 5, 6, 7, 9, 12), C
Vitamin A Function
AKA retinol; antioxidant, visual pigment component, needed for epithelial cell differentiation into specialized tissue, used as tx is all trans retinoic acid for for AML subtype (promyelocytic)
Vitamin A found in which food
Leafy vegetables
Vitamin A toxicity
Teratogenic (causes cleft palate, cardiac abnormalities; must do pregnancy test!);
acute=blurred vision, nausea, vomiting, vertigo;
chronic=dry skin, alopecia, hepatic toxicity, arthralgias, pseudotumor cerebri
Vitamin B1 name
Thiamine
Vitamin B1 function
Think ATP to remember which enzymes TPP is a cofactor for
Part of TPP, which is an enzyme cofactor for: pyruvate dehydrogenase (glycolysis-TCA cycle link),
alphaketogluterate dehydrog (TCA cycle),
transkelotase (HMP shunt, which is an NADPH source important in RBCs for glutathione),
and branched chain ketoacid dehydrogenase
Vitamin B1 deficiency
In malnutrition and alcoholism
Impaired glucose breakdown–>ATP depletion, which is worsened by glucose infusion (remember, don’t give someone with Wernicke encephelopathy just glucose!)
Very aerobic tissues are affected first (brain, heart)
Wernicke-Korsakoff: confusion, opthalmoplegia, ataxia is classic triad; personality change, memory loss (mammillary body damage)
Wet beriberi=dilated cardiomyopathy, edema
Dry beriberi=polyneuritis, symmetrical muscle wasting
Diagnosis: increase in RBC transkelotase activity after B1 replacement
Vitamin B2 name
Riboflavin
Vitamin B2 function
Think riboFlavin in Fad and FMN (TCA cycle cofactors); B2–>2 ATP
Vitamin B2 deficiency
2 C’s: cheilosis (inflammation of lips, scaling at the corners of the mouth), corneal vascularization
Vitamin B3 name
Niacin
Vitamin B3 synthesis
Derived from tryptophan
Requires B2 and B6 for synthesis
Vitamin B3 function
Niacin for NAD (B3–>3ATP); NAD is used in redox rxns
Vitamin B3 as treatment for
Dyslipidemia; lowers VLDL, raises LDL
NIACIN FLUSH* is a common side effect
Vitamin B3 deficiency symptoms
3Ds: diarrhea, dementia (+ hallucinations), dermatitis (Cassals “necklace” rash)
Hyperpigmentation of syn exposed limbs
Glossitis
Pellagra
Causes for Vitamin B3 deficiency
Hartnup disease: deficiency of tryptophan transporters in proximal renal tubular cells AND on enterocytes–>aminoaciduria, low tryptophan absorp from gut–>low tryptophan causes low niacin–>pellagra
Malignant carcinoid syndrome: increased tryptophan metabolism into serotonin pathway; diarrhea
Isoniazid: decreases vitamin B6 (pyridoxine), which is needed for B3 synthesis
Vitamin B5 name
Pantothenic acid (think 5=pento)
Vitamin B5 function
Component of CoA and fatty acid synthase
Vitamin B5 deficiency
Dermatitis, enteritis, alopecia, adrenal insufficiency
Vitamin B6 name
Pyridoxine
Vitamin B6 function
Cofactor used in transamination, decarboxylation rxns, glycogen phosphorylase
Used for synthesis of heme, niacin, histamine, neurotrans (serotonin, epineph, norepi, dopamine, GABA)
Vitamin B6 deficiency
Can be caused by isoniazid and OCPs
Convulsions, irritability, peripheral neuropathy, sideroblastic anemias (part of porph synthesis, ALAS enzyme, which is Hb component; microcytic anemia)
Vitamin B7 name
Biotin
Vitamin B7 fn
Cofactor for carboxylation enzymes that add 1-C group
Examples
pyruvate–>oxaloacetate
Acetyl CoA–>malonyl CoA
Propionyl CoA–>methylmalonyl CoA
Vitamin B7 deficiency
Caused by: antibiotics, excessive raw egg white ingestion
Avidin in egg whites avidly binds biotin
Dermatitis, alopecia, enteritis
Vitamin B9 name + food it is found in
Folate; leafy greens (folate from foliage)
B9 absorbed in
Jejunum; small storage site in liver
B9 function
Made into THF, which is part of nitrogenous base synthesis (pyramidine) for DNA and RNA
B9 deficiency cause
Drugs: methotrexate, phenytoin, sulfonamides
B12 deficiency causes folate “trap”
Small bowel disease or after resection
B9 deficiency signs/symptoms/labs
Macrocytic, megaloblastic anemia with hypersegmented neutrophils
Glossitis
NO neuro symptoms! (vs B12)
Labs: high homocysteine, nml methylmalonic acid
Most common deficiency in US; esp in alcoholism and pregnancy
Supplement in pregnant women to decrease risk of neural tube defects
B12 name and found in what food
Cobalamin; in animal products; large storage reserves in liver
B12 function
Cofactor for methionine synthase (needed for THF) and for methylmalonyl CoA mutase (needed for converting methylmalonyl CoA–>succinyl CoA)
B12 deficiency signs/symptoms/labs
Macrocytic, megaloblastic anemia with hypersegmented neutrophils
Paresthesias, subacute combined degeneration (degen of dorsal columns , lateral CST, spinocerebellar tracts), due to abnml myelin
Labs: increased homocysteine AND methylmalonic acid levels
B12 deficiency caused by
Malabsorption,
lack of intrinsic factor (pernicious anemia dx with anti-IF Abs, gastric bypass surg),
absence of terminal ileum (surg resection)
insufficient intake (vegans)
B12 site of absorption
Terminal ileum; needs intrinsic fator
Vitamin C name, which foods
Ascorbic acid; fruits and veggies
Vitamin C fn
Antiox
facilitates iron absorp,
Needed for collagen synthesis (proline and lysine hydroxylation)
Needed for dopamine–>NE rxn
Used as ancillary tx for methemoglobinemia
Vit C Deficiency
Scurvy due to collagen synthesis defect: swollen gums, bruising, petichiae, anemia, poor wound healing, perifollicular hemorrhages, corkscrew hair
Weakened immune response
Vitamin C excess
Nausea, vomiting, diarrhea, nephrolithiasis (calcium oxalate)
Can increase risk of iron toxicity in predisposed individuals
Vitamin D forms
D2=plants
D3=milk, sun exposed skin
25-OH D3=storage form
1,25OH D3 (calcitriol)=active form (made in kidney)
Vitamin D fn
Increase intestinal absorp of calcium and phosphate
Increase bone mineralization at low levels, bone resorption at high levels
Vit D deficiency
Rickets in children (bone pain & deformity)
Osteomalacia in adults (bone pain, musc weakness)
Vit D excess
Hypercalcemia, hypercalciuria, loss of appetite
Seen in granulomatous disease bc increased activation of vit D by epithelioid macrophages
Vitamin E fn
Antiox (protects from free radical damage)
Enhances anticoag effects of warfarin bc high vitamin E dose alters metabolism of vitamin K
Vitamin E deficiency
Hemolytic anemia,
acanthocytosis,
musc weakness,
posterior column and spinocerebellar tract demyelination
Presents similar to B12 deficiency (ie neuro) but without peripheral smear findings or high methylmal acid levels)
Vitamin K fn
Coagulation (factors 2, 7, 9, 10, C, S)
Warfarin=vit K antag
Synthesized by intestinal flora
Vitamin K deficiency
Neonatal hemorrhage
Increased PT and PTT (coag factor determined)
Nml bleeding time (platelet determined)
Neonates cannot synthesize vit K (injection at birth; not in breast milk)
Zinc fn
Essential mineral for activity of a lot of enzymes
Important for zinc finger (transcription factor motif)
Zinc deficiency
Delayed wound healing
Hypogonadism
Decreased adult hair (axillary, facial, pubic)
(Remember androgens are steroid hormones that bind intranuclear TFs)
Anosmia
Acrodermatitis enteropathica (enormous dark rash on skin)
May predispose to alcoholic cirrhosis
