Selenium

Question 1

How is selenium absorbed?

Answer 1

Selenium is bound to cysteine or methionine in food

• selenomethionine
• selenocystine

Is absorbed bound to these amino acids

50-100% of intake is absorbed

phytates and mercury interfere

Vitamins A, C, E help

Question 2

What is the biologically active form?

Answer 2

Selenocysteine

Used to synthesise glutathione peroxidase

Question 3

How and where is selenium stored in the body?

Answer 3

Stored as selenomethionine

Liver, pancreas, muscle, kidneys

Question 4

What is the function of selenium?

Answer 4

• part of the antioxidant defence system as a cofactor of glutathione peroxidase: prevents peroxidation and spared vitamin E
• thyroid hormone metabolism: cofactor to DIOs which converts T4 to T3

Question 5

What is the result of a selenium deficiency?

Answer 5

• decreased levels of circulating T4

- Keshan’s disease which causes enlarged heart, CVD and higher rates of cancer (not causational)

Question 6

What is caused by selenium deficiency?

Answer 6

• garlic breath
• nausea
• diarrhoea

Question 7

What are good sources of selenium?

Answer 7

• oysters, sardines
• steak
• chicken