Selenium Flashcards
What are some dietary forms of selenium?
Selenomethionine- cereals
Selenate- plants
Selenite- supplements
How is Selenium unique in biology?
Only trace element specified in the genetic code (UGA=selenocysteine)
What are the main selenoproteins?
Glutathione peroxidase, iodothyronine deiodinases, selenoprotein (P, N, S)
What does glutathione peroxidase do and give an example in the body?
Prevents against oxidative stress (peroxidation of cell membranes attacks C=C)
Removes H2O2, lipid and phospholipid peroxides.
Sperm mitochondrial capsule selenoprotein- early phase of spermatogenesis (antioxidant), later phase plays a role in structure
What do the iodothyronine deiodinases do and where are they found in the body?
They are required for thyroid hormone metabolism. Thyroxine is activated to Triiodothyronine (T3). T3 is required for growth hormone synthesis, control of thermogenesis. Combined Se and I deficiency exacerbate hypothyroidism.
What are the common sources of selenium?
Meat, Cereals, fish
What are the DRVs for selenium?
RNI- 75 men, 60 women
LRNI- 40 micrograms per day
Why has selenium intake fallen?
Drop in imports of high Se North American wheat
Changes in break-making technology
Less bread consumed (originally highest contributor)
What diseases exhibit Se definiciency?
Keshan disease
Kashin-Beck disease
What diseases have been shown to reduce in risk as a result of the action of selenium?
Cancer, CVD, immune function, reproduction, thyroid function
