Essentials of Nutrition for Sports

Studies have shown that diets with higher intakes of vitamin C
are associated with decreased in

cidence of cancers of the mouth,

throat and vocal chords, esophagus, stomach, colon-rectum, and lung. Studies have

not

shown that dietary supplements with

antioxidants reduce the risk of developing cancer.

Although antioxidants may have a role in slowing the aging

process and preventing heart disease and strokes, good studies do not prove this

4. Some studies have shown an

increased

risk of heart

attack with the use of antioxidants.

It is premature to make reco

mmendations regarding antioxidant

supplements and disease prevention.

Exercise and Oxidative Damage

Aerobic exercise can increase oxygen utilization up to 20 times

the resting state. This increases the generation of free radicals, prompting concern about enhanced

damage to muscles and other

tissues.

Do athletes need to defend against increased free radicals

resulting from exercise? Can they? Do athletes need to take extra antioxidants?

Regular physical exercise enhances the antioxidant defense

system and protects against exercise-induced free radical damage. These changes parallel other adaptations to exercise.

The role of antioxidant supplementation in well-nourished

athletes is controversial. Good studies have not proven benefit.

There is no firm evidence to support supplementation with

antioxidants.

Performance

Antioxidant supplements have not been shown to be useful as

performance enhancers.

Toxicity

Antioxidants supplements are not harmless. They have

interactions and potential toxicity.

Little is known about the long-te

rm consequences of megadoses

of antioxidants.

Bottom Line: Fruits and Vegetables

Other chemicals and substances found in natural sources of

antioxidants may also be responsible for the beneficial effects.

The best way to ensure an intake

of the antioxidant nutrients is

through a balanced diet including five or more daily servings of fruits and vegetables.

4 For a discussion about what makes a good study, see page 135. Nutrition for Sports, Essentials of 26