Selenium

Question 1

What are the chief biological functions of selenium?

Answer 1

Antioxidant and enzyme conversion of T4 to T3

Question 2

What is the antioxidant form of selenium?

Answer 2

Glutathione peroxidase (GPX)

Question 3

What are the major selenoproteins?

Answer 3

GPX-1, 2, 3, phospholipid hydroperoxide GPX (GPX-4), and iodothyronine 5’-deiodinase (DI-1)

Question 4

What determines the amount of selenium in foods?

Answer 4

The enrichment in soil, since Se is derived primarily from volcanic reactions.

Question 5

What is the efficiency of Se absorption?

Answer 5

Very efficient (80-90%)

Question 6

What is the RDA for Selenium for adults and children?

Answer 6

Adults - 55ug/d
Children - 20-60ug/d

Question 7

What is the requirement to be considered a trace element?

Answer 7

RDA must be <100ug

Question 8

List 2 food sources high in Se

Answer 8

Brazil nuts and canned tuna, but very ubiquitous

Question 9

When does Se deficiency usually occur?

Answer 9

Occurs if only consuming local sources of food without various and in an isolated area. Not very common since ubiquitous and highly absorbed.

Question 10

What is the UL of Se and the symptoms?

Answer 10

UL = 400-1000ug/d
Brittle hair and nails and garlic breath.
Vomiting and diarrhea if >2000ug/d

Question 11

Selenium can reduce the risk of what toxicity?

Answer 11

Arsenic toxicity. Take Se supplement if you know you will be at risk.