Supplements of selenium may reduce markers of oxidative stress immediately after exercise for overweight people, suggests a new study.
A daily dose of the mineral was associated with significant decreases in levels of lipid hydroperoxides after exercise. Lipid hydroperoxides are intermediates in lipid peroxidation, which is a well-known indicator of oxidative damage in cell membranes.
“This study has highlighted a potential health benefit of selenium in reducing lipid hydroperoxides levels post-exercise in overweight individuals,” the researchers wrote in the journal Obesity.
Selenium is an essential macronutrient, and is considered to be an antioxidant. The trace element occurs naturally in the soil and is absorbed by plants and crops. From there it enters the human food chain either directly or through consumption of meat and other products from grazing animals. The mineral is included in between 50 and 100 different proteins in the body, with multifarious roles, including building heart muscles, supporting prostate health and promoting healthy sperm.
Researchers from the University of Bedfordshire and Luton and Dunstable Hospital in England recruited 10 normal weight and 10 overweight people to participate in their randomized, double-blind supplementation study. Participants received a daily dose of 200 mcg of selenium for three weeks or three weeks of placebo. At the end of the three weeks, both groups received placebo for three weeks and then crossed over to the other group.
Results showed that selenium supplements were associated with a 0.25 micromole per liter decrease in lipid hydroperoxides levels, compared to placebo, in the overweight participants immediately following exercise. No changes in other markers of oxidative stress were observed between the placebo and selenium groups.
Commenting on the discrepancy between the overweight and normal weight participants, the researchers note that selenium plays a crucial role in the body’s antioxidant defenses, particularly in antioxidant enzymes, such as glutathione (GSH). This enzyme is responsible for removing various oxidizing species from the cell, such as hydrogen peroxide.
The researchers note that the overweight participants had low selenium levels at the start of the study and this may be why they expressed a “compromised antioxidant system and raised lipid hydroperoxides levels at rest and after high-intensity exercise.”
“Selenium supplementation in the overweight group was effective at increasing plasma selenium levels to near recommended levels, which in turn decreased lipid hydroperoxides responses at rest and after high-intensity exercise.
“The lack of selenium supplementation effect on lipid hydroperoxide levels in the normal weight group may be explained by prior sufficient levels of selenium to support maximal expression of GSH-Px activity,” they added.