9th June 2015
Many people take supplements to improve recovery after exercise but new research suggests this could be, at best, a waste of time or, worse, actually hinder the recovery process. Here’s why:
The traditional theory, the so-called antioxidant-exercise hypothesis, suggests that intense exercise produces high levels of free radicals, or reactive oxygen species (ROS). These damage cell membranes and DNA and impair muscle function, hastening fatigue. The imbalance is sometimes called ‘oxidative stress’. The idea behind antioxidant supplementation is to offset exercise-induced ROS damage and speed recovery.
Although previous studies have suggested antioxidant supplementation may be beneficial, these are no longer considered valid due to small subject numbers and poor study design.
Newer studies suggest that antioxidant supplements either have no effect on performance or can actually decrease training efficiency and prevent adaptation of muscles to training – the very opposite of what athletes want. Although supplements reduce post-exercise oxidative stress, this isn’t a good thing because oxidative stress is needed to stimulate muscle growth. In other words, oxidative stress and inflammation are desirable and are considered essential for training adaptations. ROS generated during intense exercise signal to the body that it needs to adapt to the stress of training by becoming stronger and more efficient. By prematurely quenching these ROS with high doses of antioxidant supplements, you could be preventing muscle adaptations.
Studies suggest that the body adapts to exercise by increasing its own antioxidant defences, making more glutathione peroxidase and superoxide dismutase. Thus, taking supplements will provide no further benefit.
A review of more than 150 studies by Australian researchers concluded that there is insufficient evidence that antioxidant supplements improve performance. And a double blind randomised controlled trial found that vitamin C (1000mg) and E (235mg) supplements blunted the endurance training‐induced increase of mitochondrial proteins, which is important for improving muscular endurance. There was no difference in aerobic capacity or performance between those taking supplements or a placebo. The researchers concluded that vitamins C and E hampered cellular adaptations in the muscles and therefore provided no performance benefit. In another study, cyclists taking antioxidant supplements experienced no performance benefit during 12 weeks of strenuous endurance training compared with those taking a placebo). In other words, supplementation with antioxidants appears to reduce rather than improve the benefits of training.
There is no benefit to be gained from taking high dose antioxidant supplements. Instead of improving performance or promoting recovery, they may actually hamper it by disrupting the mechanisms designed to deal with exercise-derived oxidative stress.
Getting your vitamins and minerals through a varied and balanced diet remains the best approach to maintain an optimal antioxidant status. There’s good evidence to suggest that a diet rich in foods that are naturally high in antioxidants is associated with better health outcomes. The following foods are particularly rich in antioxidants:
- Red/orange and green vegetables (e.g. carrots, peppers, broccoli, cabbage, spinach)
- Red and purple fruit (e.g. strawberries, blueberries, raspberries, cherries)
- Onions, garlic, leeks
- Citrus fruit
- Nuts and seeds
- Whole grains
- Tea (black, green)
- Whole grains
- Nuts and seeds
- Oily fish, avocado, eggs
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