Micronutrients Flashcards
what are vitamins?
group of chemically unrelated organic compounds
‘vital amines’
how many essential vitamins is there for regulation of body processes and normal metabolic function?
13
what does vitamin deficiencies result in?
multiple systemic complications and are linked to oral conditions
why are vitamins essential to humans?
we can’t make them
what are the exceptions to the fact we can’t make vitamins?
vitamin D = synthesised in the skin upon exposure to sun
vitamin K, some B vitamin = synthesised by gut flora
what vitamins occur in food as precursors?
- beta carotene converted to vitamin A
- tryptophan converted to niacin
what vitamins are fat soluble?
A
D
E
K
pantothenic acid B5
folate
what vitamins are water soluble?
C
& B vitamins:
thiamin
niacin
vit B6
vit B12
riboflavin
biotin
what are the features of fat soluble vitamins?
- found with fat in food
- absorbed in lymph, transported attached to protein, stored in liver or in fatty tissues
- excessive intake
what are the features of a water soluble vitamin?
absorbed directly into bloodstream, transported in free form, higher turnover in the body with little storage
- prone to leaching from food, more sensitive to heat
- generally not harmful in high doses can be harmful
what factors influence the utilisation of vitamins?
- availability
- antivitamins
- provitamins
- biosynthesis in gut by bacterial flora
- intestinal disease
how many essential minerals are there?
15 to 16
what are the main functions of essential minerals?
- constituents of bones and teeth
= calcium, phosphorus and magnesium - formation of soluble salts the help to control composition of bodily fluids
= sodium, potassium and chlorine - essential components of many enzymes and other proteins, necessary for release and utilisation
= iron and zinc
some minerals are soluble in water and others are insoluble. name 2 of each?
soluble = Na, K
insoluble = Fe, Zn
describe the bioavailability of minerals?
?????
what is the most common minerals that have deficiencies in the population?
iron and iodine
give examples of preformed vitamin A.
retinol
retinaldehyde
retinoid acid
give examples of provitamin A.
carotenoids
= beta-carotine
alpha-carotine
lutein
lycopene
beta-cryptoxanthin
what is the ratio of beta carotene to vitamin A?
1:6
where is provitamin A found?
pigments in plants (orange and yellow)
what is the most potent source of vitamin A?
beta-carotene
what are the functions of vitamin A?
growth and normal development
vision
regulation of gene expression
antioxidant
immunity
red blood cell production
cell differentiation
- tooth development, oral epithelial development
where is preformed vitamin a absorbed as retinol found in the diet?
liver
fatty fish
eggs
whole milk
cheese
butter
where ate carotenes (vitamin A) found?
dark green, leafy vegetables, red and orange fruit and vegetables eg carrots/ apricots
how does a deficiency in vitamin A effect the teeth?
decreases oral epithelial tissue development
impaired tooth formation
enamel hypoplasia
presence of periodontitis
how does a deficiency in vitamin A lead to increased susceptibility of infection?
- ↓ production of mucopolysaccharides & mucus, & ↑ tissue keratinization (e.g. xerophalmia)
- decreased anti-bacterial action of macrophages
- decreased production of lysozyme
- lymphocyte and antibody action also affected
how does a deficiency in vitamin A effect bone growth and development?
- Impaired embryological development (possible malformations)
- Impaired gene expression & cell differentiation (possible link with cancer)
- Impaired bone growth
- infertility in males, low rates of conception in females
what happens if over 200mg of vitamin A is ingested?
vomiting, headaches, blurred vision, vertigo, shedding skin, uncoordinated muscle movements
what would happen if an adult ingested 10mg of vitamin A per day for one month?
bone and muscle pain, headaches, alopecia, liver toxicity, poor muscle coordination
