Biochemistry- Nutrition Flashcards
Vitamins: fat soluble
A, D, E, K. Absorption dependent on gut and
pancreas.
B-complex deficiencies often result in…
dermatitis, glossitis, and diarrhea.
Wich Vitamins: water soluble wash out easily from body
All except B12 and B9 (folate). B12 stored in liver for ~ 3–4 years. B9 stored in liver for ~ 3–4 months
Vitamins: water
soluble
B1 (thiamine: TPP) B2 (riboflavin: FAD, FMN) B3 (niacin: NAD+) B5 (pantothenic acid: CoA) B6 (pyridoxine: PLP) B7 (biotin) B9 (folate) B12 (cobalamin) C (ascorbic acid)
Vitamin A (retinol) FUNCTION
- constituent of visual pigments
- essential for normal differentiation of epithelial cells into specialized tissue.
- prevents squamous metaplasia.
- Used to treat measles and acute promyelocytic leukemia (APL).
Use oral isotretinoin to treat..
Use all-trans retinoic acid …
- severe cystic acne.
2. to treat acute promyelocytic leukemia
Vitamin A (retinol) DEFICIENCY
(nyctalopia) ; (xerosis cutis); corneal degeneration
(keratomalacia) ; Bitot spots on conjunctiva; immunosuppression
Vitamin A (retinol) EXCESS
Acute toxicity—nausea, vomiting, vertigo, and blurred vision.
Chronic toxicity—alopecia, dry skin (eg, scaliness), hepatic toxicity and enlargement, arthralgias, and pseudotumor cerebri.
Isotretinoin is teratogenic.
Vitamin B1 (thiamine)FUNCTION
Think ATP: α-ketoglutarate dehydrogenase,
Transketolase, and Pyruvate dehydrogenase.
Vitamin B1 (thiamine) DEFICIENCY
Spell beriberi as Ber1Ber1 to remember
vitamin B1
Wernicke-Korsakoff syndrome—confusion,
ophthalmoplegia, ataxia (classic triad)
Dry beriberi—polyneuritis, symmetrical muscle
wasting.
Wet beriberi—high-output cardiac failure
(dilated cardiomyopathy), edema.
Vitamin B2 (riboflavin) FUNCTION
FAD and FMN are derived from riboFlavin
(B2 ≈ 2 ATP).
Component of flavins FAD and FMN, used as
cofactors in redox reactions.
Vitamin B2 (riboflavin) DEFICIENCY
The 2 C’s of B2.
Cheilosis (inflammation of lips, scaling and
fissures at the corners of the mouth), Corneal
vascularization.
Vitamin B3 (niacin) FUNCTION
NAD derived from Niacin (B3 ≈ 3 ATP).
Derived from tryptophan. Synthesis requires vitamins B2 and B6. Used to treat dyslipidemia.
Vitamin B3 (niacin) DEFICIENCY
The 3 D’s of B3.
Symptoms of pellagra: Diarrhea, Dementia , Dermatitis (C3/C4 dermatome circumferential “broad collar” rash).
Can be caused by Hartnup disease, malignant carcinoid syndrome ( tryptophan metabolism), and isoniazid ( vitamin B6).
Vitamin B3 (niacin)
Facial flushing, hyperglycemia, hyperuricemia.
Hartnup disease
disease—autosomal recessive. Deficiency of neutral amino acid (eg, tryptophan).
Pellagra-like symptoms. Treat with highprotein diet and nicotinic acid.
Vitamin B5 (pantothenic acid)FUNCTION
B5 is “pento”thenic acid.
Essential component of coenzyme A (CoA, a cofactor for acyl transfers) and fatty acid synthase.
Vitamin B5 (pantothenic acid) DEFICIENCY
Dermatitis, enteritis, alopecia, adrenal
insufficiency.
Vitamin B6 (pyridoxine) FUNCTION
Cofactor used in transamination (eg, ALT and AST),
decarboxylation reactions, glycogen phosphorylase.
Synthesis of cystathionine, heme, niacin, histamine, and neurotransmitters including serotonin, epinephrine, norepinephrine (NE), dopamine, and GABA.
Vitamin B6 (pyridoxine) DEFICIENCY
Convulsions, hyperirritability, peripheral neuropathy (deficiency inducible by isoniazid and oral contraceptives), sideroblastic anemias due to impaired hemoglobin synthesis and iron excess.
Vitamin B7 (biotin)FUNCTION
Cofactor for carboxylation enzymes:
Pyruvate carboxylase
Acetyl-CoA carboxylase
Propionyl-CoA carboxylase
Vitamin B7 (biotin) DEFICIENCY
Rare. Dermatitis, alopecia, enteritis. Caused by antibiotic use
Vitamin B9 (folate) FUNCTION
Important for the synthesis of nitrogenous bases
in DNA and RNA.
Absorbed in jejunum.
Vitamin B9 (folate)DEFICIENCY
- Macrocytic, megaloblastic anemia; hypersegmented
(PMNs); glossitis; no neurologic symptoms (as opposed to vitamin B12 deficiency). - Labs: homocysteine, normal methylmalonic acid
levels. - Seen in alcoholism and pregnancy.
Vitamin B12 (cobalamin) FUNCTION
Cofactor for methionine synthase and methylmalonyl-CoA mutase. Important for DNA synthesis.
Vitamin B12 (cobalamin) DEFICIENCY
Macrocytic, megaloblastic anemia; hypersegmented PMNs; paresthesias and subacute combined degeneration due to abnormal myelin.
Vitamin C (ascorbic acid) FUNCTION
Antioxidant; facilitates iron absorption by reducing it to Fe2+ state. Hydroxylation of proline and lysine in collagen synthesis. Necessary for dopamine β-hydroxylase, which converts dopamine to NE.
Ancillary treatment for methemoglobinemia by
reducing Fe3+ to Fe2+.
Vitamin C (ascorbic acid) DEFICIENCY
Vitamin C deficiency causes sCurvy due to a
Collagen synthesis defect.
Vitamin C (ascorbic acid) EXCESS
Nausea, vomiting, diarrhea, fatigue, calcium oxalate nephrolithiasis.
Scurvy
Swollen gums, bruising, petechiae, hemarthrosis, anemia, poor wound healing, perifollicular and subperiosteal hemorrhages, “corkscrew” hair.
Vitamin D FUNCTION
intestinal absorption of calcium and phosphate, bone mineralization at low levels, bone resorption at higher levels.
Vitamin D DEFICIENCY
Rickets in children, osteomalacia in adults, hypocalcemic tetany.
Vitamin D EXCESS
Hypercalcemia, hypercalciuria, loss of appetite, stupor. Seen in granulomatous disease
Vitamin E (tocopherol/tocotrienol) FUNCTION
Antioxidant. High-dose supplementation may alter
metabolism of vitamin K enhanced anticoagulant effects of warfarin.
Vitamin E (tocopherol/tocotrienol) DEFICIENCY
Hemolytic anemia, acanthocytosis, muscle weakness, posterior column and spinocerebellar tract
demyelination.
Aumented serum methylmalonic acid levels.
Vitamin K (phytomenadione, phylloquinone, phytonadione) FUNCTION
cofactor for the γ-carboxylation of glutamic acid residues. Maturation of clotting factors II, VII, IX,
X, and proteins C and S.
Vitamin K (phytomenadione, phylloquinone, phytonadione) DEFICIENCY
Neonatal hemorrhage with PT and aPTT but normal bleeding time.
Zinc FUNCTION
Mineral essential for the activity of 100+ enzymes. Important in the formation of zinc fingers
Zinc DEFICIENCY
Delayed wound healing, hypogonadism, adult hair (axillary, facial, pubic), dysgeusia, anosmia, acrodermatitis enteropathica.
Protein-energy malnutrition
Protein malnutrition
Kwashiorkor
Protein malnutrition
MEALS: Malnutrition Edema Anemia Liver (fatty) Skin lesions (hyperkeratosis/ hyperpigmentation)
Marasmus
Malnutrition not causing edema. Diet is deficient in calories but no nutrients are entirely absent.
Fomepizole
FOMEpizole—inhibits alcohol dehydrogenase and is an antidote For Overdoses of Methanol or Ethylene glycol.
Disulfiram
inhibits acetaldehyde dehydrogenase (acetaldehyde accumulates, contributing to hangover symptoms), discouraging drinking.
Ethanol metabolism increase NADH/NAD+ ratio in
liver, causing:
- Pyruvate to lactate (lactic acidosis)
- Oxaloacetate to malate (prevents gluconeogenesis fasting hypoglycemia).
- Dihydroxyacetone phosphate to glycerol- 3-phosphate (combines with fatty acids to make triglycerides hepatosteatosis).
- NADH leads to aumented utilization of acetyl-CoA for ketogenesis ( ketoacidosis) and lipogenesis ( hepatosteatosis)..
