Zinc Diseases

Question 1

What are the potential benefits associated with zinc?

Answer 1

Respiratory tract - Zn protective against pollution
Immunity and infections - HSV, cold and flu
Neurological - attention deficit
Growth and weight gain
Skin and hair
Weight management - appetite regulation

Question 2

How is zinc involved in oocytes?

Answer 2

zincosomes are subcellular structures loaded with zinc.
When egg fertilised secrete large amounts of zinc.
Zinc involved in keeping unfertilised egg in metabolically downregulated state.

Question 3

What is the: reference range for zinc.
Deficient range.
Symptomatic range?

Answer 3

Serum reference = 10.7 - 22.9 umol/L
Deficiency = below 7 umol/L
Less than 5 umol/L –> loss of taste, semll, abdo pain, rash and loss of appetite.

Question 4

Who is at risk of zinc deficiency globally?

Answer 4

Vegetarians
Pregnant and lactating women
Athletes
Alcoholics (alcohol dehydrogenase is zinc dependent)

Question 5

How is zinc toxic?

Answer 5

• excess disrupts function of bio molecules e.g. proteins and DNA.
• Anaemia - impaired CU absorption
• Acute excess intake –> GI distress, nausea, vomiting, abdo cramps.
• Air pollution - COPD, asthma.

Question 6

What is the absorption efficiency of zinc?

Answer 6

Between 15-60%
Under normal conditions 1/3 of dietary zn absorbed.
Uptake and retention higher in growing animals
Phytate lowers Zn aborption (1.3 -3.6mg requirment though!)

Question 7

What are the risks of zinc supplementation?

Answer 7

Cu deficiency
Drug interactions
Soil zinc []s have more than doubled in UK since 1843

Question 8

How is zinc excreted?

Answer 8

2 pools (fast turnover = 12.3 d, slow = ~300 days)
Main endogenous loss - secretions into gut from bile and pancreas / mucosal cells 
Urinary losses - <20% under normal conditions.