vitamins

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  • Created by: eviebrad
  • Created on: 11-01-23 18:40
vitamins key points
essential for life, needed in small amounts, do not provide energy, supplied by food
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structure of vitamins
organic compounds required for maintenance of normal health, individual units not linked together
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functions of vitamins
essential for many processes in the body, play a role in digestion and utilisation of CHO, proteins, fats, they do not yield energy, assist enzymes, and other biological factors that release energy from CHO, proteins and fats= coenzymes
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classification of vitamins
according to solubility which determines site in body which they function
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fluids outside / inside body cells
water based
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cell membranes layers / nerve tissues
fatty substances
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vitamins in watery areas
water soluble vitamins
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vitamins in fatty tissues
fat soluble vitamins
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fat soluble vitamins
A,K,D,E
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water soluble vitamins
vitamin C, B1, B2, B3 pantothenic acid, biotin, vitamin b6, folic acid, vitamin b12
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absorption of fat soluble vitamins
lymph then blood/carrier protein
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absorption of water soluble vitamins
directly into blood
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storage of fat soluble vitamins
long-term - liver and adipose tissue
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storage of water soluble vitamins
short-term not easily stored
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excretion of fat soluble vitamins
less readily excreted- remain in fat storage sites
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excretion of water soluble vitamins
kidneys detect and remove in urine
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vitamin A
retinol
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most important carotene
beta carotene
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for absorption retinol needs
bile salts, vitamin E, adequate protein
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absorption of carotene
not efficient, 9-17%, needs bile salts, fat and protein
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storage of retinol
liver, kidney and pigment layer of dye
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transport of retinol
bound to retinol binding protein and pre-albumin
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functions of retinol vitamin A
versatile, vision in dim light, bone growth, reproduction, epithelial growth and differentiation, overall growth, anti-infection
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vitamin A major constituent in vision
retina of eye, cones and rods, rods=dim light, cone=bright coloured light
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major protein in rods
rhodopsin - light sensitive, breaks down on exposure to light
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dark adaption time
speed at which eyes adjust from bright light to dim light due to vitamin A
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rhodopsin
resynthesised in the dark and broken down on exposure to light
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vitamin A deficiency
takes a long time to recover enough rhodopsin to be able to see in dim light
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night blindness
vitamin A deficiency
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vitamin A
controls differentiation of cells by inhibiting the keratinising tendency - the more vitamin A enters the cell, the greater mucus secreting nature
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deficiency of vitamin A
cells become harder and dryer, increased number of infections, specific and non-specific protective mechanisms are impaired
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immune response
enhanced by vitamin A supplementation
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factors affecting vitamin A deficiency
deficiency in low income countries, dietary inadequacy, lower liver reserves at birth, low levels in breast milk, frequent infections
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dietary sources of vitamin A
meat, liver, fats, milk, dairy, vegetables, carrots
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too much vitamin A
highly toxic, can accumulate in liver, can result in birth defects, permanent damage in the liver and eyes, reduced bone density, overdose from supplements not food
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EAR vitamin A recommendations
500ug men 400ug women 250ug children
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1 ug retinol same as what beta-carotene
6ug beta carotene same as 1 ug retinol
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vitamin D
body can synthesise with help of sunlight, given enough sunlight do not need vitamin D from food
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vitamin D aka
calciferol
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vitamin D function
bone making and maintenance, assists in absorption of dietary calcium, helps to make calcium and phosphorus available in blood
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vitamin D sources
produced in skin by UV radiation of 7-dehydreocholesterol
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7-dehydreocholesterol
vitamin D precursor that is synthesised by liver
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dietary sources of vitamin D
fish liver oil, flesh of oily fish, egg yolk, liver
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vitamin D absorbed
in the small intestine
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activation of vitamin D
starts in liver cells, hydroxylated at c25 to 25-hydroxycholecalciferol, then further hydroxylated in the kidney, to 1,25-dihydroxycholecalciferol
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dihydroxycholecalciferol
metabolically active form of vitamin D
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parathyroid hormone
essential for the hydroxylation step in the kidneys
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disease effecting liver or kidney
may impair transformation process so produce symptoms of vitamin D deficiency
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vitamin D acts on 4 sites
gut, kidney, bone, parathyroid gland
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vitamin D on the gut
calcium absorption
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vitamin D on kidney
calcium excretion
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vitamin D on bone
calcium storage and bone formation
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vitamin D on parathyroid gland
inhibits parathyroid hormone release
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low calcium
parathyroid hormone release, 1,25-dihydroxycholecalciferol synthesised, more calcium absorbed via gut, less calcium lost in urine, calcium removed from bone, increase calcium
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vitamin D deficiency
rickets- bow legs poor growth dental eruption fractures, osteomalacia- bones stopped growing, difficult to diagnose, muscle weakness, skeletal pain
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new vitamin D recommendations
RNI of 10 mg
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vitamin D toxicity
intake exceeds 10x recommendation, increase calcium absorption, calcium deposits in soft tissue, prolonged exposure to sunlight can cause cancer
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vitamin E
fat soluble antioxidant, protects other substances from being oxidised by being oxidised itself, naturally occurring tocopherol
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alpha-tocopherol
more active and abundant one
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vitamin E as an antioxidant
prevents oxidation of polyunsaturated fatty acids, protects lipids from oxidation by oxygen and free radicals
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vitamin E in the lungs
antioxidant effect where cells exposed to high oxygen concentration
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vitamin E helps prevent heart disease
protects low density lipoproteins from oxidation so prevents development of atherosclerosis
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vitamin E deficiency
rare but can occur in people who cannot absorb fats, diseases of liver, gall bladder and pancreas
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vitamin E requirements
no set DRV but intakes of 4mg men and 3mg women
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sources of vitamin E
olive oil, sunflower oil, corn oil, rapeseed oil and fatty parts of animal foods
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vitamin K
blood clotting, synthesis of proteins involved in clotting, coagulation, bone health, works with vitamin D regulate calcium
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vitamin K essential for formation of
prothrombin, factor VII, factor IX, factor X
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deficiency of vitamin K
rare- as widely distributed in food can be synthesised by gut bacteria
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groups at risk of vitamin K deficiency
new born infants, patients with defective absorption, antibiotic use
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haemorrhage disease
new born, given vitamin K injection after birth
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antibiotic use causing vitamin K deficiency
destroys gut flora
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measure diagnosis of deficiency of vitamin K
prothrombin time, time taken for blood to clot
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infant recommendation vitamin K
10ug/day
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adults DRV vitamin K
1ug/kg/day
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dietary sources vitamin K
green beans, cauliflower, sprouts, broccoli, spinach, cabbage, lettuce
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Other cards in this set

Card 2

Front

structure of vitamins

Back

organic compounds required for maintenance of normal health, individual units not linked together

Card 3

Front

functions of vitamins

Back

Preview of the front of card 3

Card 4

Front

classification of vitamins

Back

Preview of the front of card 4

Card 5

Front

fluids outside / inside body cells

Back

Preview of the front of card 5
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