Majid Koozehchian, M.S.
In our bodies, oxygen constantly produces toxic substances called reactive oxygen species (ROS), also known as oxidants. Antioxidants, biomolecules that combat oxidant damage, are produced by the body and can also be taken in supplement form. Disruption of normal cellular function by ROS is termed oxidative stress, and can be considered an imbalance between ROS production and the body’s production of antioxidants, weighted on the oxidant side (Fig.1). Low levels of antioxidants can contribute to muscle atrophy and fatigue. Further, inadequate levels of antioxidants increase age-related loss of muscle mass (sarcopenia), weakening the body and causing more susceptibility to injuries and worsening conditions affected by inactivity, such as frailty and osteoporosis.
How does exercise affect this imbalance? During exercise, the stress on muscle metabolism increases production of free radicals, a type of ROS. Unfortunately, little evidence has shown that body production of antioxidants after strenuous exercise protects skeletal muscle cells during recovery.
Does an athlete need more dietary antioxidants?
The simple answer is yes, an athlete needs more dietary antioxidants, for several reasons. During endurance exercise, whole-body oxygen consumption increases 10-20 fold, and up to 100-200 fold in active skeletal muscles as opposed to a resting state. Fortunately, oxidative damage can be minimized or prevented by antioxidants. However, poor dietary habits or caloric restriction for weight control can increase risk of oxidative damage due to inadequate antioxidant intake.
Does antioxidant supplementation improve physical performance?
Muscle fatigue occurs when a muscle’s ability to generate force decreases, i.e. when its functional limit has been met. However, there’s another factor at work – free radical production. It is believed that ROS play a part in contracting skeletal muscles; however, if the ROS level is too high, it can cause oxidative damage to muscle proteins and/or lipids and decrease muscle force production. Scavenging excess free radicals by antioxidants can protect skeletal muscles against oxidative damage and delay fatigue during prolonged submaximal exercise. So there are several situations in which body production of antioxidants may be inadequate: poor dietary habits, weight control, and muscle fatigue. Supplements can be helpful in these cases.
Three critical antioxidant supplements to consider
Certain non-enzymatic antioxidants are more relevant to athletes: glutathione, coenzyme Q10, vitamin E, vitamin C, lipoic acid, and carotenoids. Each provides important benefits.
GSH helps stabilize body immunity and neutralizes harmful effects of free radicals in the body. It also helps to remove toxins from the body, fight Parkinson’s disease, and fortify other antioxidants so that they perform optimally.
Coenzyme Q10 (CoQ10)
CoQ10 is well-known for its ability to support cardiovascular function. CoQ10 is a vitamin-like compound that aids in the production of 95% of the body’s energy, because it’s found primarily in mitochondria. The highest concentrations of CoQ10 are located where energy is most needed – heart, liver, and kidney.
Alpha lipoic acid (ALA)
ALA is a multipurpose nutrient with potent antioxidant and glucose-control actions. As an "insulin mimicker," ALA is not only capable of increasing glucose uptake by muscle cells, it decreases the glucose uptake into fat cells, resulting in increased energy production in muscles and less fat stored.
The bottom line is that although athletes need to make sure they have an adequate antioxidants intake, it is unreasonable to take excessive amounts of only one or two antioxidants. Athletes, especially endurance trainers, need to consume a wide variety of effective plant-based antioxidants. Also, little evidence supports the short term benefit(s) of antioxidants for athletes; so long term usage of different antioxidants likely produces more health benefits.
Further related information related to antioxidants:
- Oxidative stress, exercise, and antioxidant supplementation: Urso and Clarkson. Toxicology. Volume 189,Issues 1-2, 15 July 2003, Pages 41-54
- Reactive oxygen species are signalling molecules for skeletal muscle adaptation. Powers, Duarte, Kavazis, and Talbert, Experimental Physiology,2010,95, 1-9
Fig.1. Relationship between oxidants and antioxidants. An increase in oxidants or antioxidants results in a disturbance in cellular redox balance.