Exercise increases oxygen consumption to levels between 10 and 15 times above values at rest. The main biological product of exercise are the oxygen reactive species, or ROS, which damage cell membranes and skeletal muscles. ROS are counteracted by the antioxidant defence systems of the body, for whom Selenium (Se) is an important factor.
Selenium is a minor, or trace element, in mammals, that can be found in seafood, lentils, beans, whole grains, organ meats, dairy and vegetables. It has two important functions:
- Antioxidant, as protective of oxidative damage, specially through the enzyme glutathione peroxidase.
- Modulation of the immune system, with a protective role against viral infections.
Se dietary intake has been set at 55 micrograms/day, with usual dietary supplements offering levels between 180 and 240 micrograms/day, usually in the form of selenomethionine or sodium selenite. Levels above 400 micrograms/day are known to cause selenosis disease, characterised by an increased breakability of hair and nails.
Because of the properties of Se it could be useful to improve athletic performance, fasten muscles recovery and increase defence systems. Thus, Se supplementation is often used as an aid for sports. But does it really offer any improvement in performance?
A recent meta-analysis studied the available scientific literature to answer this question. From all articles available, only 6 complied with the inclusion criteria.
Data showed no evidence of beneficial effects on aerobic or anaerobic performance while using Se supplementation.
Despite this lack of performance improvements, Se supplementation could contribute to keep optimal antioxidant levels on active individuals, help in the recovery process and prevent viral infections.
The article points out to the importance of optimal Se levels in blood as a preventive strategy against viral infections, such as the one from Covid-19.
Keep healthy and active and see you soon.
The Role of Selenium Mineral Trace Element in Exercise: Antioxidant Defense System, Muscle Performance, Hormone Response, and Athletic Performance. A Systematic Review. Fernández-Lázaro D, Fernandez-Lazaro CI, Mielgo-Ayuso J, Navascués LJ, Córdova Martínez A, Seco-Calvo J. Nutrients. 2020;12(6):1790. Published 2020 Jun 16. doi:10.3390/nu12061790