zinc and copper Flashcards

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1
Q

zinc is essential in the function of what enzymes

A

carbonic anhydrase
superoxide dismutase
polymerases
kinases
nucleases
transferases
phosphorylases
transcriptases

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2
Q

what is zinc essential for

A

growth
cell division
bone formation
integrity of skin (collagen)
immunity
synthesis of lean tissue
appropriate insulin response

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3
Q

what percentage of zinc is in our body pool

A

60%

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4
Q

how many grams of zinc are in skeletal muscle

A

2g

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5
Q

what percentage of zinc in our body is in bone

A

30%

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6
Q

what percentage of our zinc is in our skin

A

5%

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7
Q

what are sources of zinc

A

Red meat
Seafood (oysters; mussels)
Poultry
Dairy products
Leafy and root vegetables
Wholegrains

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8
Q

whats the EAR for men and women for zinc

A

Males 7.3 mg/d
Females 5.5 mg/d

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9
Q

whats the RNI for men and women of zinc

A

Males 9.5 mg/d
Females 7.0 mg/d

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10
Q

how much of the zinc we consume is absorbed

A

30%

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11
Q

what can a lack of zinc in diet lead to

A

Genetic disorder:
acrodermatitis enteropatica
zinc deficiency

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12
Q

what are symptoms of zinc deficiency

A

Skin lesions (infected; skin; knees; buttocks)

Impaired growth

Poor sexual development

Impaired glucose tolerance

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13
Q

what are some inhibitors of zinc absorption

A

Phytate
Oxalate
Polyphenols
Folate
Iron
Copper
Calcium

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14
Q

explain zincs interaction with vit A

A

metabolism of retinol to retinal (alcohol dehydrogenase) hepatic synthesis of retinol binding protein (Zn deficiency)

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15
Q

what can zinc supplementation lead to

A

copper deficiency (metallothionein)

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16
Q

what is the tolerable upper limit of zinc per day

A

40 mg/d

17
Q

what are the 2 forms of copper

A

(cuprous [Cu1+] and cupric [Cu2+])

18
Q

what is copper required for

A

superoxide dismutase

lysyl oxidase

cytochrome c oxidase (ETC)

amine metabolism (tyramine,histamine, dopamine, 5-HT, polyamines)

Synthesis of noradrenaline from dopamine
19
Q

what is Superoxide dismutase in terms of copper

A

anti-oxidant enzyme removing superoxide radical (O2-) with protons to form O2 and H2O2

20
Q

what is lysyl oxidase in terms of copper

A

crosslinks connective tissue proteins e.g collagen, elastin

21
Q

what is tyrosinase for, in terms of copper

A

Synthesis of melatonin

22
Q

what are some more roles of copper

A

immune system

nerve myelination

angiogenesis

transcription regulation
23
Q

what are some sources of copper

A

Seafood (shellfish; 0.3-4.4 mg/100 g)
Liver (4.5 mg/100 g)
Red meat (0.1 mg/100 g)

Nuts and seeds (1.1-2.2 mg/100 g)
Legumes (0.25 mg/100 g)
Dried fruits (0. 3 mg/100 g)

note: low in milk (premature babies)

24
Q

what is the RNI for copper

A

1.2 mg/d

25
Q

where is the active carrier mediated for copper absorption

A

principally in small intestine; more in cuprous (Cu1+) form

26
Q

what percentage of copper is absorbed

A

50%

27
Q

what enhances copper absorption

A

some amino acids
eg histidine, methionine, cysteine

28
Q

what are inhibitors of copper absorption

A

phytate, zinc, iron, calcium, phosphorus, ascorbic acid

29
Q

whats menkes disorder cause by in terms of copper

A

X-linked disorder of transport between intestine and peripheral tissues

30
Q

how is copper transported

A

Transported in blood attached to ceruloplasmin (liver; ferroxidase I):

Also oxidase and anti-oxidant, involved in oxidation of minerals e.g ferrous (Fe2+) to ferric (Fe3+)

Also acute phase protein involved in scavenging free radicals of oxygen (inflammation)

31
Q

what are some copper deficiencies

A

Anaemia (poor mobilisation of iron)
Osteoporosis (demineralisation)
Low pigmentation (melatonin)
Poor immune function
Neurological, cardiovascular and respiratory abnormalities