NUTR2101 Lecture Notes - Lecture 12: Bone Mineral, Hydroxylapatite, Garlic Bread
Wednesday, 23 May, 2018
Trace Mineral 3
Zinc
-Absorption:
-simple diffusion
-prefer lower pH so absorption occurs in upper duodenum *same for calcium
-high dose higher absorption but will get out of control
-phytic acid target zinc reduce absorption (phytate)
-yeast used to isolate zinc increase absorption (leaven bread)
-alcohol impaired zinc absorption *also water soluble vitamins B1 B2
-reason why thiamin added to bread
-thiamin impaired as well in chronic alcoholic person
-B2 riboflavin presence act as carrier of zinc to enterocyte;
-non-haem iron impaired absorption since often fibre goes with green leafy
-promote synthesis of body metallothiomin; binding zinc like ferritin binding iron act like
‘mucosal block’
-modulates how much zinc in blood similar to ferritin
-if high dose taken, absorption override mucosal block and the binding control lost
-no main storage, mainly zinc pool where different body organs uses *like vitamin C
-excretion as faeces
-factors affecting zinc absorption: when take low to moderate, intake more likely to
absorb more, riboflavin increase absorption when requirements needed
-excessive no good lower is better since too much override metallothionin production;
override mucosal block
-involve neurological function *similar function with iodine
-3 categorises function:
-catalytic: when zinc as cofactor ADH; folate conjugate converting polyglutamate to
monoglutamate in folate; SOD involve in oxidative damage
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Wednesday, 23 May, 2018
-Structural function: bone formation; bone health; protein structure and cell membrane
fingerlike structure stabilise protein receptor on surface of cell for vit a and d
absorption since enter only when present of receptors; stabilisation is important role of
healthy bone
-regulatory role: gene expression zinc finger like protein act as transcription factor in
promotor region; involve in gene expression; prevention of chronic disease check
apotheosis of cell; when cell dies and not functioning in the way
-there is UL; too much not good
-deficiency; anorexia loss of appetite result poor growth, not the same as adult no
cretinism in adult since nervous system dev
-decrease in taste sensation
-can be lack of intake can be need increase requirement e.g. chronic alcohol uses zinc
for metabolism then increase demand will increase urine excretion and mineral loss
-toxicity through supplement
-involve in reproductive system; sperm motality immune formula with zinc and Vit C
-compete absorption of other minerals
-found particularly in seafood oysters, meat and vegetarian sources are limited
-vegan at risk since limited in vegetarian products
Copper
-absorption phytic inhibition; no mucosal block but excess intake bind inside enterocyte
like metallothiamin; bit of storage
-ceruloplasmin transport protein and has enzyme activity for iron; when entering bs
transported as transferrin into the blood
-Fe3+ for circulation need conversion; ceruloplasmin is one of the enzymes (the other
one is hephaestin) which can do the conversion
-metalloenzyme hephastin(main) and cerriloplasmin
-lack copper not as efficient entry of iron to blood
-cofactor copper SOD copper antioxidant enzyme cytochrome C found in ETC like iron
-in bone mineral has role in bone health
-crosslink of fibres assisted by copper with elastin and collagen fibre
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Document Summary
Prefer lower ph so absorption occurs in upper duodenum *same for calcium. High dose higher absorption but will get out of control. Phytic acid target zinc reduce absorption (phytate) Yeast used to isolate zinc increase absorption (leaven bread) Alcohol impaired zinc absorption *also water soluble vitamins b1 b2. Thiamin impaired as well in chronic alcoholic person. B2 ribo avin presence act as carrier of zinc to enterocyte; Non-haem iron impaired absorption since often bre goes with green leafy. Promote synthesis of body metallothiomin; binding zinc like ferritin binding iron act like. Modulates how much zinc in blood similar to ferritin. If high dose taken, absorption override mucosal block and the binding control lost. No main storage, mainly zinc pool where different body organs uses *like vitamin c. Factors affecting zinc absorption: when take low to moderate, intake more likely to absorb more, ribo avin increase absorption when requirements needed.
