A well-planned out triathlon training program will enhance your physical fitness and optimize your health, but all the hours spent swimming, biking, and running also results in increased output of highly reactive substances known as free radicals that can cause injury to skeletal muscles and may also contribute to muscular fatigue during endurance events. 7,30
Free radicals are produced anytime oxygen is processed, which makes free radical production a commonality among all endurance athletes. In fact, up to 30 times more oxygen is produced during exercise secondary to deep breathing patterns and increased metabolism1,6, with 2-4% of it resulting in the generation of free radicals.8,12
Fortunately, our bodies are able to naturally ward off some of the free radical damage with the help of antioxidant enzymes and compounds, all of which work at different sites within the body.2,15 Physical training can increase the activity of the enzymes that ward off free radicals, but there is some evidence that our natural antioxidant defenses can be overwhelmed during high intensity or high volume training, thereby increasing muscle damage.2,4,5,7,11,14,16,17,18,25,26,27
Furthermore, critical tissues, such as the heart, have lower levels of protective antioxidant enzymes, thereby making them increasingly susceptible to free-radical damage.7 Consequently, sport scientists have been exploring the potential performance benefits of dietary and supplemental intake of antioxidants.
A diet rich in whole grains, legumes, nuts, fruits, and vegetables provides superior antioxidant protection but for the athlete whose food intake revolves around processed convenience foods or whose food intake is restricted, antioxidant supplementation may help to maintain the integrity of cell membranes, enhancing the blood's oxygen carrying capacity and positively affecting aerobic performance.
Furthermore, some reports indicate that nutrients from food required by the body to maintain our antioxidant enzymes are lost because of many agricultural issues, including soil degradation, ripening, storing, drying, cooking, freezing, blanching, pasteurization, hydrogenation, ultra-filtration, hormone injection and a myriad of other "modern" food processing procedures.10
There is a plethora of antioxidants spotting the supplement aisle, including the most popular vitamins: vitamin A, vitamin C, and vitamin E, as well as the less known compounds oligomeric proanthocyanidins (OPCs), Alpha Lipoic Acid, grape skin, grape seed, beta-carotene, lutein, and tocopherols, tocotrienols.
According to research, a few months of consuming more antioxidants in the form of colorful fruits and vegetables and potentially supplementing with an antioxidant compound may reduce incidence of infection, quicken recovery and enhance daily performance. Below, I explore the roles of the major antioxidant players among athletes, specifically beta-carotene, vitamin C, and vitamin E.
What Are Antioxidants?
- Compounds that protect against cell damage inflicted by molecules called oxygen-free radicals, which are a major cause of tissue damage, disease and aging.
- Includes vitamin C, vitamin E, selenium and carotenoids, (such as beta-carotene, lycopene, and lutein).
Belonging to a large class of compounds called carotenoids, beta-carotene helps to stimulate detoxifying enzymes, protect against free radical damage, and enhance immune function.27 Just 30 mg of beta-carotene has been shown to significantly elevate plasma carotene concentration and add some protection against the oxidative stress occurring during intense training.28
|Beta-Carotene (1/2) retinol equivalents|
|Sweet potato (1/2 cup)||2,800|
|Red bell pepper (1/2 cup)||285|
|Broccoli (1/2 cup)||70|
|Spinach (1 cup)||375|
Beta-carotene is especially potent when taken in coordination with vitamins C and E, helping to reduce post-exercise muscle damage and reduce incidence of upper respiratory function. In fact, this antioxidant cocktail has been reported to reduce incidence of upper respiratory infection by almost 40%.19 To naturally boost your intake of beta-carotene, look for the color orange in the produce section.
Vitamin C (a.k.a ascorbic acid)
The only vitamin present in every cell of the body, vitamin C plays several important roles in the body, including serving as a potent antioxidant that helps neutralize free-radical molecules and protect against muscle damage during intense training.7,21
While performance does not seem to be enhanced by vitamin C supplementation in healthy athletes, untrained or vitamin C-depleted individuals have been shown to exhibit reduced work efficiency and performance during sub-maximal exercise.13 Furthermore, research suggests that athletes engaged in heavy endurance training have greater vitamin C requirements than others.
|Vitamin C (1/2) milligrams|
|Red bell pepper (1/2 cup)||95|
|Cantaloupe (1/2 cup)||35|
|Broccoli (1/2 cup)||60|
|Spinach (1 cup)||15|
One study showed that runners supplementing with 600 mg of vitamin C daily for 3 weeks prior to the South African Comrades Marathon (90-km running race) reduced the incidence of post-race upper-respiratory tract infection by more then 50%.20 An intake of 800-2000 mg of vitamin C split into several smaller doses each day is recommended by some health professionals.
Note that excessive vitamin C has been documented to solicit diarrhea and joint pain among other problems so be aware of overdoing supplemental vitamin C, which is often found in sport foods as well as the ever-so-popular Emergen-C packets which contain 500 mg vitamin C per packet. To naturally boost your intake of vitamin C, aim at covering each meal plate with 50% fruits and vegetables.
While endurance training improves the body's enzymatic antioxidant defense, muscle and other tissues consume vitamin E during increased physical activity making vitamin E supplementation potentially beneficial for protection against exercise-induced free-radical damage.3,4,7,17,22,24,29
|Vitamin E (1/2) milligrams|
|Wheat germ (1 Tbsp)||3.9|
|Hazelnuts (1 oz)||5.8|
|Almonds (1 oz)||4.2|
|Sunflower seeds (1 oz)||2.3|
|Safflower Oil (1 Tbsp)||4.6|
|Almond oil (1 Tbsp)||5.3|
|Sunflower (1 Tbsp)||6.1|
In fact, vitamin E, which is a fat-soluble vitamin made up of several compounds known as tocopherols, has been touted the most powerful antioxidant due to its ability to maintain cell membrane integrity. This quality has been shown to help accelerate post workout recovery by protecting against muscle protein breakdown and reducing muscle inflammation and soreness.
One study showed that men supplementing with 1000 IU of vitamin E daily for 12-weeks significantly reduced the level of muscle damage seen after 45 minutes of downhill running at 75% VO2 max.23
Because vitamin E is fat-soluble, athletes on a low-fat diet may benefit from the use of vitamin E. Furthermore, several studies have found that the recommended daily value for vitamin E, 30 IU, is rarely obtained from diet alone. Research has yielded positive results from doses ranging from 400-1000 IU. Vitamin E is most effective as a recovery aid when consumed in combination with vitamin C. To naturally boost your intake of Vitamin E, snack on almonds, sprinkle wheat germ in yogurt, slice avocado onto sandwiches, and cook with sunflower oil.
Boosting Antioxidant Intake Naturally
Every meal plate should contain foods providing plenty of color, especially fruits and vegetables. Fruits and vegetables, especially those with a deep hue, are loaded with antioxidants, which help protect our immune cells from harmful oxygen molecules called free radicals.
Studies have found that individuals consuming at least 5 servings of fruits and vegetables each day display the highest antioxidant protection. Follow a menu similar to that seen below to help enhance your antioxidant protection!
Sample 2,000 Calorie Antioxidant-Rich Menu
The Bottom Line
Triathlon training can create a large amount of free radicals, especially during base training when most workouts are aerobic in nature. During high intensity and high volume training, the body's natural defenses against these harmful substances may not be able to counter the negative effects of free radicals, thereby increasing muscle damage and risk for injury.
Recent research has investigated whether dietary antioxidants, especially beta-carotene, vitamins C and E, can help this situation by blocking the actions of free radicals in the cell. It is apparent that athletes with poor dietary habits or those training in extreme environments (altitude, heat, pollution) may benefit from supplementation with antioxidants.
However, based on information currently available, there is insufficient evidence to support the need for antioxidant supplementation in athletes who consume a well-balanced diet that is rich in fruits and vegetables.