AFTER CANCER: PREVENTING NEW CANCERS. ANTIOXIDANTS

What Are Antioxidants?

Antioxidants are micronutrients (substances found in tiny amounts) that serve as the body’s primary defense against free radicals and reactive oxygen molecules (two by-products of normal metabolism that are thought to cause damage to normal cells, possibly predisposing the damaged cells to become cancerous). If free radicals trigger the early changes of cancer, then antioxidants would protect patients by mopping up these free radicals. Antioxidants include

• carotenoids

• beta-carotenes

• vitamin С

• vitamin E

Selenium is an essential component of antioxidant enzymes.

What Are the Facts regarding Antioxidants as Protection against Cancer?

Animal studies suggest a protective role for antioxidants in the fight against various types of cancer, particularly lung and epithelial cancers. We cannot draw conclusions about humans on the basis of animal studies. The results from animal studies help us proceed to human studies in a safe and expeditious manner. Human studies have shown an association between

•a diet low in carotenoids and an increased risk of lung cancer

•a diet low in vitamin С and an increased risk of oral, esophageal, and stomach cancer

•a diet high in vitamin С and beta-carotene and a decreased risk of cervical dysplasia and oral leukoplakia

•a diet high in vitamin С and a protective effect against cancers of the esophagus, mouth, stomach, pancreas, cervix, rectum, breast, and possibly lung

•low blood levels of beta-carotene and an increased risk of lung cancer

•low blood levels of vitamin С and an increased risk of stomach cancer

These and other data certainly suggest that antioxidants protect against some types of cancer. Well-designed human studies are under way to determine definitively which antioxidants in what dose and form guard against which specific cancers.

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