Antioxidants are an essential part of any diet and assist the body in removing free oxygen from our body which is toxic. As reactive gas oxygen likes to bind with other molecules in the body, forming reactive oxygen species (ROS). ROS are reactive because they are hungry for electrons, and tend to “steal” them from other molecules they come into contact with, which causes cellular damage. For this reason, ROS needs to be kept under tight control. The body has multiple ways to accomplish this, and antioxidants from food and supplements are one of them.
While antioxidants in the diet are essential for good health, some studies have suggested that antioxidant supplements may not be so great in the context of your workout. Initially studied as a possible way to prevent muscle soreness and enhance recovery, the effect of antioxidants on exercise adaptation has a rough track record. Previous research in human subjects has shown that high-dose supplementation with vitamin E and C can negate some of its health-promoting effects, particularly on glucose metabolism and insulin signaling. Other studies have shown that antioxidants may decrease exercise performance or delay recovery.
A recent study sheds some new light on how antioxidants may interfere with muscle building, potentially by suppressing the ability of muscle cells to repair their cell membranes after exposure to a heavy load. Muscle cell membrane damage causes calcium to rush inside of the cell. Mitochondria absorbs the calcium which triggers increased ROS production. Researchers found the increase in mitochondrial ROS production was essential to repair the membranes of muscle and other cell types after injury and microtears from training.
The major take-home is that antioxidant supplements around training time could potentially have a negative impact on your ability to recover and build muscle. Athletes should consume antioxidants through whole food sources outside peri nutrition, the nutrition eaten in the hours around and during training time. It may also be wise to avoid daily very-high-dose antioxidant supplements if aiming for maximum muscle growth and sports recovery.