Selenium is an essential trace mineral indispensable for your cat's body, albeit in small quantities. It occurs naturally in various food sources and plays an integral role in many biological processes.

A primary function of selenium is its powerful antioxidant activity , which helps safeguard your cat's cells from damage inflicted by unstable molecules known as free radicals. These free radicals are natural byproducts of metabolism, but excessive levels can overwhelm your cat's defenses and contribute to various health complications.

Selenium serves as a key component of antioxidant enzymes, such as glutathione peroxidase (GPx), which effectively neutralizes these harmful free radicals.

While selenium's importance for the immune system is well-documented across various animal species, research specifically on cats is still evolving. A recent study investigated the impact of selenium supplementation, both alone and with Vitamin E, on feline immune parameters.

Key findings reveal that while selenium supplementation alone showed limited immune benefits , the combination of selenium with Vitamin E demonstrated significant enhancement of immune function, particularly for phagocytic activity of peripheral blood leukocytes. The research indicated that Vitamin E played a more prominent role in stimulating lymphocyte proliferation and overall immune response, suggesting that the synergistic effect of both nutrients offers superior immune support compared to selenium supplementation alone, which showed minimal impact on immune cell markers, IgG concentration, and PGE2 levels in healthy cats.

It's important to note that this research involved healthy cats with diets already meeting recommended selenium levels. The findings suggest that in cats with sufficient dietary intake, supplementing with additional selenium alone may not substantially boost measured aspects of immune function.

The minimum dietary requirement for selenium in cats is 0.3 mg/kg of dry matter (DM). Overt signs of selenium deficiency appear relatively uncommon in cats under normal dietary conditions.

Research on growing kittens suggests a minimum dietary concentration of 0.4-0.5 mg/kg DM to account for potential low bioavailability.

In many species, maintaining selenium intake within a narrow range is crucial. In dogs, excessive selenium intake is considered above 5 mg/kg of diet, with signs including nausea, vomiting, diarrhea, loss of appetite, hair loss, and cardiovascular changes.

Cats, however, exhibit a unique selenium metabolism . Their serum selenium concentrations increase linearly with dietary intake without reaching a clear plateau, and they appear to tolerate higher levels compared to other species. Currently, no specific maximum selenium intake is established for cats.

Some wet cat food formulations contain selenium levels that could be toxic to other species (up to 6.12 mg/kg DM), although low bioavailability in seafood-based products and cats' apparent tolerance might mitigate this risk.

The aforementioned study also explored combined effects of selenium and Vitamin E on immune health. While the combination enhanced phagocytic activity of peripheral blood leukocytes, this enhancement was not significantly greater than Vitamin E supplementation alone for most immune parameters.

This suggests that in cats with adequate selenium levels, adding selenium to Vitamin E supplementation may not consistently provide added benefits for all aspects of immune function.

Selenium is an essential trace mineral supporting your cat's overall health and immune function. Current evidence indicates that a combination of high-quality commercial diet formulated for your cat's life stage and dietary supplements containing selenium provides the most comprehensive support for your cat's immune health.

For any concerns regarding your cat's diet and health, always consult with your veterinarian for personalized guidance tailored to your feline companion's specific needs.