57.vitamins and minerals Flashcards
What are vitamins
organic substances, that are not produced in body ( insiffienct amount ) so need to be taken in by diet
most act like catalysts for chemical reactions in human body
What is main source of vitamins
food - for vitamins we cant produce ourselves
(getting from food more advantagous than getting fro complex biosynthesis)
what is hypovitaminoses
- avitaminoses
reduced vit intake causes development of metabolic disorders.
- complete abscence of vitamins, severe symptoms and fatal outcomes
some vit act as antioxidants - what does this mean
they neutrakize free radicals( made by oxidation in cells that cause damage)
what are the fat soluble vitamins
A D E K - they not excreted in urine much
how do u get hypervitaminoses
increased dietry intake, delayed excretion of vit therefore accumulates a lot - toxic damage to body
where are lipid soluble vits absorbed and stored
absorbed in SI with lipids and stored in liver and adipose tissue
Vitamin A - forms
animal origin: retinol (alcohol), retinal (aldehyde), retinoic acid (acid) - RETINOIDS
plant origin (vit A precursors) :carotene (pigment for photosynthesis) beta caroten has highest activity (converted to retinal with B carotene diocygenase. (all carotenes can be converted to retinoids)
where is vit A stored
liver
vitamin A function
–they are ligand to retinoid receptors.
. Transcriptional activator regulating gene expression during embryonic development and cell diff in postnatal period
. for normal growth of cells and normal functioning of visual, reproductive and immune systems
vitamin A deficiencies
. stunted growth adolesecents.
. Atrophy of testicular germinal epithelium and interuppted menstrual cycle
. Night blindess (less photosensitive pigments) less vision at night
Vitamin A sources and intakes
retinoids: butter, cheese, egg, liver
carotenes: carrots, sweet potato, spinach
900 microgram adult, 700 children
Vitamin D - forms
plant origin = ergocalciferol
animal origin = cholecalciferol
they only differ by side chains
vitamin D synthesis
synthesis requires UV
on surface epidermis epithelium
. 7-dihydrocholesterol coverted to cholecalciferol with UV
Vit D sources
FISH - they obtain it by ingesting algae that get uv
UV
Vitamin D function
they bind to specific receptors in nuclei of target cells . this activates transcriptional factors and reg gene expression of transports proteins
** they steroid + thyroid hormone receptors
. expressed in brain, heart, skin, gonads..
** maintaince of calcium and phosphorus levels
Vitamin D deficiencys
bone + muscle pain, weakness
. RICKETS (children) - softening and deform of bones/ teeth
hypervitaminosies = calcification of soft tissue and kidney stone formation due to increase calcium plasma levels
vitamin D intake
5 microigram adults
10 micrograms children
vitamin E forms
8 compounds - 4 tocopherols and 4 tocotrienols.
only alpha tocophenol has vit E activity
vitamin E function and found
accumulates in adipose tissues. found in muscle tiss and cell membr
. its an antioxidant ( enhanced by vit C)
vit E hypovitaminosis
anemia - reduced erythro membrane resistance and CNS disorders
vit E sources and intake
vegetable fats, leafy greens, nuts
8 miligrams adult, 7 children
vitamin k function
for formation of blood clotting factors
. carboxylation of glutamate residues of prothrombin and clotting factors 7,9,10.
. activation of calcium binding proteins (prevents bone fractures)
vit k deficiencies
*** primary def rare bc bacteria and diet we obtain it
. secondary can develop after antibiotic treaatment which destroys inestinal flora
. hypovitaminoses in newborns - high cos their sterile digestive T theres no bacteria to synthesise it + breast milk is low in it
hypervitaminosis rare cos body excretes it faster than other vitamins
vit K sources and intakes
leafy greens + liver
. 65 micrograms adults
30 micrograms children
what are watersoluble vitamins
readily dissolved in aqeous medium and excess easily controlled in renal excretion
. hypervitaminosis is therfore rare here
what are the water soluble vitamins
vit C
vit B1,B2, B3,B5, B6,B7, B9,B12
> B grops are components of coenzymes that are activarted after prior modifications in body
vitamin C forms
ascorbic acid (reduced) + dehydroascorbi-ascorbate (oxidised)
. ascorbic acid/ascorbate is an antioxidant