Selenium is a microelement necessary for proper metabolism. Its most important role is in close cooperation with vitamin E - together they create the body’s antioxidant shield (being part of the enzyme glutathione peroxidase), which protects cells against damage and slows down the aging process. Therefore, it is probably not neutral in the prevention and treatment of cancer [1] [2]. In addition, selenium is necessary for the proper functioning of the thyroid gland (it determines the transformation of its hormones into the active form), and also strongly supports the immune and reproductive systems and participates in the synthesis of DNA. [1] [2]. The selenium content in natural dietary ingredients is slightly lower than in ready-made foods, but selenium of natural origin is probably more bioavailable than from processed products [2].
What it contains: Red muscle meat, offal (mainly kidneys and liver), sea fish meat (salmon, cod) and, in smaller quantities, egg yolks [1].
Deficiency: Rarely occurs alone, usually goes hand in hand with vitamin E deficiency. It leads to weakness and soreness of skeletal muscles, subcutaneous edema, anorexia, depression, shortness of breath and cardiac muscle dysfunction, and even to coma [2].
Excess: Chronic overdose with supplements leads to selenosis. Classic symptoms include: a characteristic smell of garlic from the animal’s mouth, matting and massive hair loss, brittle and deformed claws, and severe liver and kidney damage. [3]. Symptoms of chronic food poisoning include: anorexia, emaciation, anemia, growth retardation, and ascites. Nervous system disturbances such as staggering may occur. Acute poisoning is fatal [2].
Sources
- National Research Council (2006). Nutrient Requirements of Dogs and Cats. National Academies Press. https://nap.nationalacademies.org/catalog/10668/nutrient-requirements-of-dogs-and-cats
- Zentrichova V, Pechova A, Kovarikova S (2021). Selenium and Dogs: A Systematic Review. Animals 11(2):418. https://pmc.ncbi.nlm.nih.gov/articles/PMC7915357/
- Merck Veterinary Manual. Selenium Toxicosis in Animals. https://www.merckvetmanual.com/toxicology/selenium-toxicosis/selenium-toxicosis-in-animals