Zinc, Selenium, Molybdenum

Question 1

what are the main functions of zinc

Answer 1

maintains integrity of skin, improves wound healing, necessary for taste, mobilizes vitamin A from liver

Question 2

blood pressure regulation is NOT a function of

Answer 2

Zinc

Question 3

biomarker used for Zinc assessment

Answer 3

serum metallothionein

Question 4

what are populations at risk of zinc deficiency?

Answer 4

elderly, vegans, preschool picky eaters, alcoholics

Question 5

how does zinc function in gene expression?

Answer 5

zinc is KEY cofactor for transcription factors that stabilize proteins through zinc fingers to bind DNA and regulate gene expression ->
enables proteins to control transcription and/or translation of specific genes

Question 6

where did discovery of zinc deficiency happen and why? what are the results?

Answer 6

-Iran in males with short stature and underdeveloped sexual organs
-diets high in phytates from chickpeas and pita (unleavened bread)
-chewing clay (pica) = bound up zinc
-treatment: zinc supplements for increased height, weight and sexual development

Question 7

how can trace element status influence lead toxicity in children?

Answer 7

-deficiency of >2 trace elements (iron, zinc or copper) could increase absorption of LEAD (they compete for intestinal absorption)
-in deficiency, competition decreases so lead absorption increases
-ex: when children eat old paint chips with lead (well nourished children would ABSORB less but poor trace element status = more)

Question 8

role of zinc in host defense and immunity? how does it compare to Cu and Fe?

Answer 8

-Zinc: promotes differentiation and proliferation of T cells = influence cell survival
-infection: lowered plasma zinc by sequestering in liver, hard for pathogens to grow and replicate
-also decreases plasma Fe because Fe is sequestered in ferritin
-plasma Cu increases b/c high Cu from macrophages fights infection

Question 9

2 mechanisms for Zn absorption

Answer 9

1. active transport (with ZIP4 or DMT1 transporters) which is 7-9 mg
2. passive diffusion (when intake exceeds ZIP4 capacity) >20mg

Question 10

populations at risk of selenium deficiency + who is NOT at risk

Answer 10

vegans/ veg, patients getting TPN, people undergoing kidney dialysis, HIV

*NOT at risk: young children

Question 11

vitamins substitute for some functions of selenium

Answer 11

vitamin E

Question 12

highest level of selenium in the body

Answer 12

Thyroid

Question 13

consequence of molybdenum toxicity? cause and consequence

Answer 13

gout, a painful deposit of uric acid crystals in a joint (molybdenum interferes with uric acid metabolism in the body, inhibits its excretion)

Question 14

why was sulfur used as food additive and no longer used?

Answer 14

sulfites were used as an antioxidant to prevent browning of foods. no longer used because a lot of people are allergic to it.

Question 15

name and cause of selenium deficiency in china in 60/70’s? how is it different form other deficiencies?

Answer 15

-Kesan disease
-low selenium in soil (deficiency) + Coxsackie virus
-due to a virus, virus created mutations, increased requirements of selenium

Question 16

molybdenum interaction with copper, what happens with high intakes in cattle and humans? how can it be useful in medicine?

Answer 16

-Mo prevents Cu from binding to plasma proteins
-cattle; high levels of Mo = Cu deficiency anemia
-humans: inhibit angiogenesis (blood vessel growth) can be therapy for cancer and macular degeneration

Question 17

populations experiencing Mo toxicity? consequences? and include quantities

Answer 17

-soil in Armenia has high levels, resulted in dietary intake of 10-15mg/d
-upper limit is 2 mg/ da
-toxicity led to gout, crystal deposits of uric acid

Question 18

selenoprotein, how prevalent in nature? what do they do?

Answer 18

-about 25
-what: protein with selenium inserted in place of sulfure in methionine and cysteine
-why: protect oxidative modification of lipids, reduce inflammation, prevent platelet aggregation

Question 19

kashin-beck’s disease, where did it occur? what mineral is it related to and why?

Answer 19

-China
-osteoarthropathy and degeneration of joints
-eating grains contaminated by a fungus, caused production of mycotoxins and radicals
-selenium effective treatment for antioxidant activity

Question 20

What is white muscle disease? In which species does it occur? What are the consequences and treatment?

Answer 20

-muscle fiber degeneration, giving muscle tissue a white color
-caused by selenium and/ or vitamin E deficiency
-normally seen in young calves