Vitamins Flashcards
fat soluble
A (retinol, beta carotene)
D (cholecalciferol, ergocalciferol)
E (tocopherol)
K (naphthoquinone)
water soluble
C (ascorbic acid) B Group: B1 (thiamine) B2 (riboflavin) B6 (pyrodoxine) B12 (cobalamin) folic acid niacin
forms of vitamin A
retinol (pure vit A)
-animal sources
eg fish, fish oils, butter
beta carotene
-brightly coloured fruit and veg
eg carrots, apricots, tomatoes
functions of vit A
- produces rhodopsin to aid night vision
- essential for lining membranes
- aids growth and repair of cells
- healthy hair and skin (antioxidant)
effects of vit A deficiency
- night blindness
- xerophthalmia (dry eyes)
- stunted growth in children
- dry mucous membranes - rough and dry skin
vit A RDA
children - 400-500mcg
adolescents - 600-700mcg
adults - 600-700mcg
pregnancy/lactation - 950mcg
properties of vitamin A
retinol
- yellow fat soluble alcohol
- insoluble in water
- heat stable
- reduced by dehydration
beta carotene
- bright orange or yellow oil
- insoluble in water
- heat stable
- sensitive to dehyration
hypervitaminosis - excess vit A
causes- dry skin enlarged liver fatigue hair loss risk of birth defects and miscarriage death
types of vitamin D
cholecalciferol
from sunlight or food eg oily fish
-sunlight converts 7 dehydrocholesterol in the skin to cholecalciferol
ergocalciferol
from fungi or yeast
-action of the sun converts ergosterol to ergocalciferol
functions of vitamin D
strong bones and teeth
aids absorption of calcium and phosphorous
prevents rickets and osteoporosis
regulates blood calcium levels
effects of vit D deficiency
rickets in children
osteomalacia
osteoporosis
dental decay
vit D RDA
children - 10mcg
adolescents - 15 mcg
adults - 10 mcg
pregnancy/lactation - 10 mcg
properties of vit D
white crystalline solid fat soluble insoluble in water stable to heat stable to acids, alkalis and oxygen
hypervitaminosis - excess vit D
more common among young children than adults due to high concentration of calcium in the blood
symptoms- nausea mental confusion vomiting and thirst loss of bone mass
vit E sources and deficiency
margarine, egg yolk, spinach, pulses
rare for the majority of the population
functions of vit E
- acts as an antioxidant
- destroys free radicals -reduces effects of aging
- protects healthy blood cells from damage
- strengthens immune system
- helps ease pre-menstrual tension
properties of vit E
fat soluble antioxidant insoluble in water delays rancidity and oxidation damaged by alkalis, oxygen and light heat stable, stable in acids
vit K sources
plant: green veg, cereals
animal: meat, liver, eggs
body: made by bacteria in the gut
functions of vit K
- for synthesis of prothrombin, essential for clotting blood
- regulates calcium balance in bones
effects of deficiency in vit K
delayed clotting of blood
vit C functions
antioxidant, prevents CHD and some cancer
helps white cells fight infections - strong immune system
essential for collagen formation
strong bones and teeth
essential for absorption of non haem iron
effects of a deficiency in vit C
scurvy in severe cases
anemia
slower healing of cuts and wounds
bruising and bleeding due to weaker blood vessels and tissues
RDA of vit C
children: 45mg
adolescents:60mg
adults:60mg
pregnancy/lactation:80mg
properties of vit C
white crystalline acid with sharp flavour
destroyed by alkalis, dry/moist heat and enzymes
acts as an antioxidant
affected by metals eg copper, iron
