Game Plan for Recreational & Professional Athletes
by Connie Guttersen, RD PhD,
author of the Sonoma Diet
The Olympics and all the glory that accompanies these games will be the focus this summer. This historic event has driven many to pursue a life of training and discipline for the love of competition. Today, many health professionals have also dedicated time to study the effects of health and nutrition on physical performance during exercise.
Sports nutrition is an area where nutritionists can provide valuable information to both professional and recreational athletes. In past years, the ideal diet for the athlete has been quite controversial--from dietary supplements and potions to more realistic approaches which focus on the quality of calories consumed. In recent years, antioxidant nutrients have received increasing attention as possible protectors of oxidative damage incurred by athletes involved in strenuous training.
How appropriate that the prize for victors at the Olympics was a simple olive branch, which was cut with a gold-handled knife, from a wild olive tree. The Greeks believed that the vitality of the sacred tree was transmitted to the recipient through the branch. This same olive tree branch, fruit, and olive oil contain many of the antioxidants which modern research confirms to be essential to the athlete's performance. TOP
Free Radicals & Exercise
Dietary antioxidant research is important because the increase in free radicals generated during strenuous exercise may exceed the body's antioxidant defense system. Exercise produces an increase in oxygen consumption reflecting the muscles use of oxygen to provide energy. As oxygen use increases so does the production of free radicals. It is well known that free radicals can be generated from metabolic situations, which occur as a result of strenuous training.
The metabolic picture relates to balance. Exercise, diet, physical condition and environment are factors, which also play an important role in the balance equation. The body's enzymatic antioxidant defense system (superoxide dismutase, glutathione peroxidase, and catalase) as well as the non-enzymatic antioxidants (vitamins C, E, and beta carotene) are part of the muscles' elaborate defense system to inactivate free radicals.
| Free Radical Damage To the Body |
| |
| Cellular DNA Damage: Cancer |
Premature Aging |
| Atherosclerosis |
Suppressed Immune Function |
| Poor Recovery from Exercise / Muscle Damage |
| Free Radical Damage following Strenuous Exercise in Combination with Poor Diet |
| |
| Increased oxygen consumption |
Increased lactic acid production |
| Injury and inflammation |
Increased catecholamine production |
| Increased muscular fatigue |
|
A study published in May 2004, found that 6 weeks of supplementation of vitamins E (300 mg alpha tocopherol) and C (1000 mg) prevented endurance exercise induced lipid peroxidation in ultra marathon runners. But research has gone beyond the elite athlete to show how important diet is for recreational athletes too. When lifestyle modification included a 4-month treatment plan of exercise, antioxidant therapy, and stress management, there was an increase in circulating antioxidants in the blood stream and a reduction in the circulating product of oxidative stress. Additional studies have also found that vitamin C supplementation decreased muscle soreness in elite athletes after strenuous training.
 Just as a balance between antioxidant intake and free radical production are important, various other factors make some people more susceptible than others to free radical damage. Research indicates that individuals with poor quality diets and deficiencies in antioxidants are more susceptible to damage. Additional factors include living in highly polluted areas, smoking, and certain diseases such as diabetes. TOP
Antioxidants & Diet
Regular exercise, which is not as intense as what is seen in elite athletes, may be associated with a compensatory increase in cellular defenses against free radical damage. These defenses involve several mechanisms such as enhanced antioxidant enzyme activity and changes in protective immune responses. These antioxidant enzymes are synthesized in the body and include certain thiols, glutathione and ubiquinone. Important antioxidants, which cannot be synthesized in the body must come from the diet. These include vitamins C, E, and beta carotene. Cross sectional studies indicate that athletes have higher antioxidant enzyme levels than sedentary individuals. If this is to be true, one could conclude that physically active individuals may indeed be more resistant to free radical damage. Training studies have also confirmed that there appears to be a relationship between weekly training distance and antioxidant capacity. The more trained the individuals, the more likely they are able to counteract an increase in free radicals generated by exercise. The "weekend warrior" who may exercise strenuously only on occasion, may be most at risk for oxidative damage to cells. The key message for a nutritionist to understand is that since strenuous exercise may deplete the pool of antioxidant vitamins, nutrient density and quality of the diet must be addressed in order to provide adequate amounts of these vitamins. One cannot assume that a normal balanced diet is always going to be adequate to provide sufficient antioxidant levels.
The following is a summary of key points related to dietary antioxidants in the Athletes Diet
- Selenium
Important for the synthesis of glutathione peroxidase (antioxidant enzyme produced in the body) in cells and organs. Dietary whole grains as well as organic vegetables can be good sources of selenium.
- Vitamin E
Important for decreasing lipid peroxidation. There is a linear relationship between the amount of unsaturated fat in the diet and lipid peroxidation. Polyunsaturated fats are more susceptible to free radical damage than are monounsaturated fatty acids. Healthy fats such as olives, olive oil, nuts, and avocados not only provide stable monounsaturated fats but are excellent sources of vitamin E.
- Vitamin C
Research has confirmed Vitamin C to reduce the incidence of post-race symptoms of upper respiratory tract infection in ultra marathon runners. This benefit may be associated with greater requirements of vitamin C during extreme endurance events.
- Copper, Managanese, Zinc, and Selenium
Minerals which act as co-factors for antioxidant enzymes and internal body defense systems against free radical damage.
TOP
|
 Designing Optimal Diets For Athletes.
Designing an optimal diet for the athlete must consider two approaches. The first is to provide enough calories to support the body's energy requirement of exercise training. These calories must be balanced to ensure the proper fuel substrate utilization during and after exercise. The recommended balance is 55 - 60% carbohydrate, 30% fat, and 15% protein or 1.2 to 1.8 gms / kg / day. The second approach is to make the calories count. Emphasize nutrient density by prioritizing foods within each food group so as to deliver the most nutrients per calorie consumed. Antioxidants, such as vitamin C, E, beta carotene and phytochemicals are most predominant in fruits, vegetables, beans, legumes, and monounsaturated fats such as olives, nuts, olive oil, and avocados. Stress to athletes the importance and difference between empty calories versus nutrient dense calories. The pyramid below communicates the idea of prioritizing the intake of most nutrient dense foods first.
TOP
|
