What Are Antioxidants?

What Are Antioxidants?

Antioxidants are molecules that are available in whole foods and dietary supplements which are known to help promote health and prevent disease. They prevent oxidation, a natural process which leads to the formation of free radicals. Free radicals are unstable or chemically reactive molecules that can trigger a series of dangerous chain reactions leading to cell damage or death. In short, antioxidants prevent cell damage and death by binding to these free radicals before they can destroy other cells, thus protecting the body from premature aging and chronic disease.

Naturally occurring antioxidants may be found in the body while others come from the diet. They may exert their effects independently and/or synergistically. Examples of powerful antioxidants that are naturally synthesized in the body include glutathione, melatonin, and uric acid while those that are obtained mostly from the diet include vitamin C and vitamin E.

How They Work

Oxidation is part of the natural process of metabolism that continuously goes on in the body. Although normal body processes produce some free radicals, the body keeps them in control through the synergistic actions of natural antioxidants produced in the body.

Antioxidants obtained from foods in the diet also help control these changes. However, with repeated free radical attacks, continuous damage can occur, leading to the development of chronic diseases like heart disease, cancer, Parkinson’s disease, and Alzheimer’s disease. This is why there is a need to augment one’s defenses by including more antioxidant sources in the diet.

Antioxidant Enzymes: The Body’s Natural Defense

The body produces several enzymes like glutathione that act as antioxidants. Other important antioxidants that are manufactured in the body are lipoic acid and coenzyme Q-10. However, the body needs nutritional building blocks like manganese, zinc, copper, iron, and selenium from food sources to produce these enzymes.

The amount of antioxidant enzymes in the body depends on different factors such as genetics and age. The body’s ability to produce enzymes may be limited by one’s genetic background, but this does not mean that good health cannot be maintained. Eating a wide variety of foods and supplementation can help increase one’s enzyme activities.

As you get older, the production of these antioxidant enzymes diminishes. As a result, mature adults often have lower levels of antioxidants. Food sources may not be sufficient to cover these deficiencies and supplements may be needed to augment your levels.

Food: the Best Antioxidant Sources

The biggest class of antioxidants is the flavonoids, of which around 5,000 types have been identified. These antioxidants are found in a variety of fruits and vegetables. Other types of antioxidants found in fruits and vegetables are phytochemicals called polyphenols.

Other foods that contain antioxidants are herbs and spices like ginger, garlic, turmeric, and cinnamon, and nuts like pecans and walnuts.

US Department of Agriculture (USDA) scientists analyzed more than 100 different foods for their antioxidant concentration as well as their antioxidant capacity per unit serving size, and have found that blueberries, cranberries, and blackberries ranked highest among fruits. Among the vegetables, artichokes, Russet potatoes, and beans were the best sources, while walnuts, pecans, and hazelnuts topped the nut category.

Antioxidants from Dietary Supplements

Professional health care providers advise people to eat a balanced diet that includes various types of foods as a source of nutrients in promoting health and preventing disease. However, there are many reasons why they may also prescribe or advise taking dietary supplements to improve the nutritional status of people, especially the elderly, athletic individuals, or those suffering from chronic illness.

The benefits derived from taking antioxidant supplements like multivitamins are many, including improved appetite, physical performance, and mood. Improvements in cholesterol and blood sugar levels, prevention of dementia and other neurologic disorders and other benefits have also been seen when supplementing with antioxidants.


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  4. Mann, D. Use of Dietary Supplements on the Rise. WebMD.