Biochemistry: Nutrition Flashcards
1
Q
Fat Soluble Vitamins
A
A, D, E, K
Absorption dependant on gut and pancreas.
- Malabosorption syndromes (steatorrhea) such as cystic fibrosis and sprue or mineral oil intake can cause fat-souble vitamin deficiency
- Toxicity is more common than in water soluble vitamins
2
Q
Water soluble vitamins
A
B1,B2,B3, B5,B6,B7,B9,B12
Vitamin C
- All wash out easily from body except B12 and folate (stored in liver)
- Deficiencies result in dermatitis, glossitis, diarrhea
3
Q
Vitamin A
A
- Anti-oxidant
- constituent of visual pigments (retinal)
- Prevents squamous metaplasia
- Used to treat measles, AML and subtype M3
- Found in liver and leafy vegetables
- Deficiency
- Night blindness
- dry, scaly skin, alopecia
- corenal degeneration
- immune suppression
- Toxicity
- Arthralgia
- Skin changes, alopecia
- cerebral edema
- pseudotumor cerebi
- osteoporosis
- hepatic abnormalities
- Teratogenic (cleft palate)
4
Q
Vitamin B1
A
Thiamine
- Thiamine pyrophosphate (TPP) is a co-factor for dehydrogenases
- Pyruvate dehydrogenase
- Alpha ketoglutarate dehydrogenase (TCA)
- Transketolase (HMP shunt)
- Branched chain ketoacid dehydrogenase
- Deficiency
- impaired glucose breakdown–> ATP depletion
- highly aerobic tissues are affected first
- Wernicke-Korsakhoff: confusion, opthalmoplegia, ataxia, personality change, memory loss
- Dry Beriberi: polyneuritis, symmetrical muscle wasting
- Wet Beriberi: high-output cardiac failure (dilated cardiomyopathy), edema
5
Q
Vitamin B2
A
Riboflavin
- FAD & FMN
- used as co-factors in redox reactions
- succinate dehydrogenase in TCA
- Deficiency
- Cheilosis
- Corneal vascularization
6
Q
Vitamin B3
A
Niacin
- NAD, NADP
- Used in redox reactions
- derived from tryptophan
- Used to treat dyslipidemia ( lowers VLDL and raises HDL)
- Deficiency
- Glossitis
- Pellagra ( Diarrhea, Dementia, Dermatitis)
- Excess
- Facial flushing (induced by prostaglandins), hyperglycemia, hyperuricemia
7
Q
Vitamin B5
A
Pantothenate Acid
- Component of CoA
- co-factor for acyl transfers and fatty acid synthase
- Deficiency
- Dermatitis, enteritis, alopecia, adrenal insufficiency
8
Q
Vitamin B6
A
Pyridoxine
- Pyridoxal Phosphate (PLP)
- transamination reactions (ALT & AST)
- decarboxylation reactions
- glycogen phosphorylase
- Synthesis of cystathionine, heme, niacin, histamine, neurotransmitters (epinephrine, noreepinephrine, dopamine, GABA)
- Deficiency
- Convulsions, hyperirritabiity, peripheral neuropathy, sideroblatic anemia due to impaired hemoglobin synthesis and iron excess
- Deficiency inducible by isoniazid and oral contraceptives
9
Q
Vitamin B7
A
Biotin
- Cofactor for carboxylation enzymes ( add 1 carbon group)
- Pyruvate carboxylase
- acetyl-coA carboxylase
- propionyl-coA carboxylase
- Deficiency rare
- dermatitis, alopecia, enteritis
- caused by antibiotic use or excessive ingestion of raw egg whites
10
Q
Vitamin B9
A
Folic Acid
- Converted to tetrahydrofolate (THF)
- co-factor for 1 carbon transfer/methylation reactions
- important for synthesis of nitrogenous bases in DNA and RNA
- Found in leafy green vegetables
- absorbed in jejunum
- small reserve pool stored in liver
11
Q
Vitamin B12
A
Cobalamin
- Cofactor for homocysteine methyltransferase and methylmalonyl Co-A
- Found in animal products
- Very large reserve pool stored in liver
- Deficiency caused by insufficient intake (vegan, malabsorption, lack of intrinsic factor, gastric bypass or absence of terminal ileum)
- Deficiency
- macrocytic, megaloblastic anemia
- Hypersegmented PMN
- paresthesia and subacute combined degeneration due to abnormal myelin
- associated with increased in serum homocysteine and methylmalonic acid levels
12
Q
Vitamin C
A
- Anti-oxidant
- facilitate iron absorption by reducing it to Fe2+ state
- Necessary for hydroxylation of proline & lysine in collagen synthesis
- necessary for dopamine B-hydroxylase ( Dopamine–> NE)
- Found in fruits and vegetables
- Ancillary treatment for methemoglobinemia by reducing Fe3+ to Fe2+
- Deficiency
- Scurvy: swollen gums, Brusing, hemarthrosis, anemia, poor would healing, perifollicular and subperiosteal hemorrhages, corkscrew hair
- Weakened immune response
13
Q
Vitamin D
A
D2: Ergocalciferol (plants)
D3: cholecalciferol (milk)
- formed in sun exposed skin
- 25 OH D3= storage
- 1,25 OH D3: active form
- Function:
- increase intestinal absorption of calcium and phosphate
- Increase bone mineralization
- Deficiency
- Rickets (child) bone pain and deforminity
- Osteomalacia in adults
- Breast fed children should receive oral vitamin D
- Excess
- Hypercalcemia
- Hypercalciuria
- loss of appetite, stupor
- seen in sarcoidosis (increase in activation of vitamin D by epithelioid macrophages)
14
Q
Vitamin E
A
Tocopherol
- Antioxidant
- protects erythrocytes and membranes from free radical damage
- can enhace anti-coagulant effect of warfarin
- Deficiency
- Hemolytic anemia
- acanthocytosis
- muscle weakness
- posterior column and spinocerebellar tract demyelination
15
Q
Vitamin K
A
- Co-factor for gamm-carboxylation of glutamic acid on proteins required for clotting
- Factors II, VII, IX, X
- Protein C & S
- Wafarin: vitamin K antagonist
- Deficiency
- Neonatal hemorrage with increase PT and PTT
- Can occur after prolonged use of antibiotics
- Not in breast milk ( neonates are given vitamin K injection at birth)
