micronutrients Flashcards
give an overview of vitamins & micronutrients
- vitamins, minerals and trace elements are fundamental groups of nutrients to sustain life
- they have a physiological role at the cellular level
- vitamins, organic molecules are derived from plants, act as co-enzymes in metabolic pathways
- minerals and trace elements participate in wide rationing cellular mechanisms
how many vitamins do humans require?
13
what are the 4 fat soluble vitamins?
A, D, E, K
what are the nine water soluble vitamins?
vitamin C and the 8 vitamin Bs
what are the 7 vitamin Bs?
- thiamine: B1
- riboflavin: B2
- niacin: B3
- pantothenic: B5
- vitamin B6
- folate: B9
- vitamin B12
what are you deficient in when you have alcohol liver disease?
- thiamine (B1)
- vitamin D
what are you deficient in when you have inflammatory bowel disease?
- iron
- B12
- vitamin D
- vitamin K
- folic acid
- selenium
- zinc
- vitamin B6
- vitamin B1
what are you deficient in when you are obese?
- vitamin D
- copper
- zinc
name the 4 water soluble vitamins
- vitamin C
- B1
- B2 (riboflavin)
- B12
name the dietary source, site of absorption and mechanism of absorption for vitamin C
- dietary source: food of plant origin
- site of absorption: buccal mucosa, stomach, small intestine
- mechanism of absorption: buccal - passive diffusion, GI absorption is rapid and via carrier-mediated transport system
name the dietary source, site of absorption and mechanism of absorption for vitamin B1
- dietary source: common in all food
- site of absorption: jejunum and ileum
- mechanism of absorption: at low concentrations by active Na+ dependent processes and at high concentration by passive diffusion
what do you get if you are low in vitamin C?
scurvy
what do you get if you are low in vitamin B1?
Wernicke Korsakoff Syndrome
name the dietary source, site of absorption and mechanism of absorption for vitamin B2 (riboflavin)
- dietary source: in most foods in coenzyme form
- site of absorption: small intestine
- mechanism of absorption: 2 stage process released from proteins - proteolytic enzymes and then hydrolysed by brush border enzymes
name the dietary source, site of absorption and mechanism of absorption for vitamin B12
- dietary source: synthesised by microorganisms
- site of absorption: distal portion of ileum
- mechanism of absorption: pepsin and HCl release B12 from proteins and B12 bind with transcorrin released from salivary glands/in bile/gastric and pancreatic secretions . In jejunum B12 released from TC and binds to intrinsic factor
what do you get if you are low in vitamin B12?
pernicious anaemia
what are the 2 fat soluble vitamins?
- vitamin A
- vitamin D
name the dietary source, site of absorption and mechanism of absorption for vitamin A
- dietary source: long chain fatty acid found in animals
- site of absorption: small intestine, carotenes upper region of SI (duodenum and jejunum)
- mechanism of absorption: protein-retinol complex hydrolysed by pepsin in stomach and other proteolytic enzymes in SI and then absorbed, carotenes solubilised into micelles absorbed through membrane and concerted to retinol
name the dietary source, site of absorption and mechanism of absorption for vitamin D
- dietary source: animal food, synthesis in skin from UV light
- site of absorption: small intestine 50% is absorbed, dietary vitamin D2, UV light vitamin D3
- mechanism of absorption: absorbed from mixed micelle by passive diffusion into intestinal mucosal cell. The liver 25-hyroxylase enzymes convert vitamin D2 and D3 to the main circulating vitamin which is the converted by the kidney and other tissues to the active form
what are the risk factors of vitamin D deficiency?
- pigmented skin
- lack of sunlight exposure
- skin concealing garments or strict sunscreen use
- multiple short interval pregnancies
- elderly or housebound
- vegan/vegetarian or high phytogeography consumption such as in chapatis
- malabsorption
- uses of anticonvulsants, rifampicin, cholestyramine, anti-retrovirals
name the dietary source, site of absorption and mechanism of absorption for calcium
- dietary source: dairy products, plant products
- site of absorption: primarily duodenum, jejunum, fermentation of plant products in colon
- mechanism of absorption: 20-30% is absorbed in an acid medium. Vitamin D-dependent calcium transport system the intake is low and requirement high, passive process when intakes are high
name the dietary source, site of absorption and mechanism of absorption for iron
- dietary source: haem iron in animal food, non-haem iron in plant food
- site of absorption: primarily proximal small intestine
- mechanism of absorption: haem iron is absorbed as intact porphyrin complex. Non-haem iron ionised from ferric to ferrous form 35% or iron absorbed when stored are low and 5% with normal iron status
what are some roles of calcium?
- egg activation
- early embryonic events
- right-left axis patterning
- organ development
- bone formation
- blood clotting
- brain function & neurotransmission
- heart function
- muscle function
what are some of the roles of iron?
- function role in all cells
- oxygen-binding site of haemoglobin and myoglobin
- synthesis of many proteins
- necessary for the synthesis of DNA
- helps produce nerve-signalling neurotransmitters
- boosts immune system and wards off infections, bacteria and viruses
