28/07/2025
Excellent write up of how Vit E and Selenium worth together to enhance muscle, thyroid and immune systems functions all while reducing inflammation and improving wellbeing and athletic performance of our beloved horses.
Well done Rosie Fookes
Hello all! With the Vet Services promo including a selenium level blood test, l thought it may be handy to have a basic understanding of why horses need selenium! Thanks heaps xx
The Basic Actions of Selenium in the Horse
Selenium’s (Se) main function in the horses diet is acting as an antioxidant. Selenium
actually works with vitamin E to achieve it’s antioxidant purpose in the horses body. As
well as an antioxidant, selenium also works and contributes in thyroid gland function,
muscle function and immunity. Selenium is an important component of glutathione
peroxidase. Glutathione peroxidase is (NRC, 2007) an antioxidant in the body that aids in
detoxification of lipo and hydrogen peroxides that are toxic to cell membranes and
intracellular structures. Glutathione peroxidase functions to remove the free radicals that
are created from the breakdown of carbohydrates to water, carbon dioxide and energy in the
body. Selenium and vitamin E coordinate with each other to protect cells and biological
tissue from these free radicals created during oxidation. Free radicals can be very damaging
to the muscle and cell membranes, as well as DNA. Selenium and vitamin E work within
different parts of the free radical cells. Selenium works works in the cell so it’s able to
destroy the cell once it has been created, while vitamin E works in the cell membrane to
help prevent its initial formation. Having adequate selenium in the horses body reduces
oxidative stress, and therefore reduces inflammation and enhances the horses immunity.
Selenium is also required in the equine body for muscle function, development and growth.
Selenium aids in the action of muscle repair and regeneration. When selenium destroys the
peroxides in the body, that therefore prevents the loss of muscle cell membrane integrity.
Selenium is (Wareham, 2023) used along with vitamin E to aid in the prevention against
muscle disorders, a common example is exertional rhabdomyolysis, commonly known as
“tying up”.
Selenium is important for thyroid gland function as it aids in controlling the thyroid
hormone metabolism. Selenium acts in thyroid function, (NRC, 2007) as the enzyme
responsible for deiodination (removing iodine from a compound) is a
selenoenzyme/selenoprotein, these enzymes/proteins require selenium to function
efficiently. The deiodinating enzyme produces most of the circulating T3 and type I
iodothronine 5 - deiodinase, and the most activity from this occurs in the horses liver,
kidneys and thyroid. If the horse is unable to produce these enzymes/proteins due to lack of
selenium, then their thyroid function, metabolism and health will reduces