Vitamins Flashcards
which vit can be synthesised by the body
Vit D via sun/UV
B and K from gut bacteria
vitamins are
chemically dispartate
functions of Vit
co enzymes hormones cell signalling antioxidant regulators of growth and differentaiton
lack of absorption of vitamin may depend on
- reduced absorption can lead to deficiency
- properties of the food
- pre existing disease (impaired fat absorption, low acid in stomach can also affect, B12 cannot be absorpted unless in low acid)
- drugs may compete for absorption, kill bacteria
foetus is senstive to
high amounts of Vitamin A
Recommended daily allowance
intake that is adequate to ensure all requirements of all healthy people are met
fat soluble vitamins
- A
- D
- E
- K
water soluble vitamins
B
C
which type of vitamins can we store
fat soluble
cannot store water
Vitamin A
retinoids (Active form(
carotenoid pigments in plants cleaved to yield retenoids
functions of Vitamin A
- binds to proteins (opsin) in the cells of the retina to form visual pigments
- nuclear modulator of gene expression
- lipid souble factor that can pass through cell membrane as it is hydrophobic
- can then bind to an intracellular receptor
- then translocated to nucleus
- associated with an area of the DNA to influence transcription/translation
Through this mechanism vit a can influence
- cell proliferation
- differentiation (especially epithelia)
- development
vit A deficiency
blindness
impaired resistance to infection (lymphocytes and neutrophils affected)
Metaplasia and keratinisation of the conjunctiva epithelial cells
Vit D active formes
- Vitamin D3 Calciol/cholecalciferol
- Vitamin D2 ercalciol/ergocalciferol
hormone precusor
functions of vit D
- maintenance of plasma calcium concentration (along with parathyroid hormone and calcitonin
- Steroid hormone activating nuclear receptors and influencing over 50 genes
bone metabolisms
Vit D stimulated phosphate and calcium absorption in gut
renal absorption of Ca
-osteobalst have receptors for calcitriol
osteoclast activity/num increased
promotes formation and mineralisation of bone
vit D deficiency
rickets and osteomalacia
failure of bone mineralisation
impaired immune system
vit E
lipid soluble
free radical trapping
Vit K
- Coenzyme in posttranslational carboxylation (adding another carboxyl group) of glutamate to Y carboxyl glutamate (gla) (modification of proteins)
- allows it to coordinate with calcium
- allows binding of proteins to membrane phospholipids
- clotting
Vit K and clotting
involved in blood coagulation
- thrombin factor 7 and 10 protein C S Z required vitamin K for funciton
where does clotting occur
phospholipid surfaces
Vit B
allco enzymes
bind to protein/enszymes
requires proteins for biological activity
types of Vitamin B
vit B12 and b9
niacin (b3)
riboflavin (b2)
Thiamin B1
Thiamin
co enzyme in central energy yielding pathways (pyruvate and kept glutamate
these produce ATP
co enzyme in pentose phosphate pathway (synthesis for nucleotides)
what is acetyl Co A used to make
myelin and acetyl choline
neurotransmitters, myelin
Riboflavin B2
electron carriers in metabolism reactions (mitochondrial electron transport chain)
bound to enzyme
niacin b3
precursor of co enzymes NAD and NADP
electron carries in metabolic redox reactions
what is niacin b3 synthesised from
dietary trytophan
vit B6
pyridoxal phosphate
co factor in transamination reaction in aa metabolisms
vit B12 and b9
co enymes
involved in DNA and myelin synthesis
vit b12 and 9 defificney
anaemia and neurological damage
vit C
reducing sugar and antioxidant
role of Fit C
role in enzyme classes
- dopamine B hydroxylase: synthesis of adrenaline and noradrenaline (Cu+ dependant, vit keeps copper + not 2+)
- Lysine and proline hydrolases: maturation of connective tissue (collagen)
Involved in Iron uptake
- keeps iron as Fe2+ (not 3+)by chelating it and reducing it which increases absorption
vitamins are involved in and relate to dentistry by
wound heeling
bleeding
resistance to infection
bone/tooth Ca2+
