Before you learn anything else about them, you probably want to know: what are antioxidants?
Antioxidants are nutrient compounds produced by your body and also obtained from eating antioxidant-rich foods. Antioxidants can be vitamins, minerals, or other phytochemicals (plant chemicals).
There are over 900 known phytochemicals (and countless other unknown ones) found in foods, and one serving of a fruit or vegetable may have as many as 100 different ones. Phytochemicals are antioxidants that are responsible for the bright colors in certain fruits and vegetables. Lutein makes corn yellow, lycopene makes tomatoes red, carotene makes carrots orange and anthocyanins make blueberries blue.
Phytochemicals are substances that plants naturally produce to protect themselves against the stress caused by intense sunlight and harsh growing conditions, as well as viruses, bacteria, and fungi. When you eat plant foods, you get the same antioxidant protection for yourself. These phytonutrients are considered nonessential nutrients, meaning that they are not required by the human body for sustaining life. However, it would be foolish to assume that they don't have powerful benefits for optimal health.
The primary purpose for antioxidants is to protect your cells from free radical damage. Free radicals are highly reactive oxygen molecules created as a normal byproduct of your metabolism. Free radicals are considered to be a primary cause of aging. When these particles are allowed to roam freely and become too numerous, you have oxidative stress, now considered one of the primary causes of aging and degenerative diseases.
In addition to the antioxidants that you get from foods, your body also manufactures antioxidant enzymes.
To learn more about how antioxidants protect you from oxidative stress, see the following page: How Do Antioxidants Work?
The action of antioxidants in the body were only discovered recently, with the invention of the electron microscope. This powerful technology led to the development of a completely new branch of science called cell biology. It was the first time that scientists were able to look inside the human cell and observe antioxidants at work.
Dr. Denham Harmon, an organic chemist
at the University of California, Berkeley,
first discovered and isolated antioxidants in 1954.
Dr. Harmon observed how antioxidants extended the life spans of laboratory animals, and how they offered protection against heart disease, cancer, brain disease, arthritis, cataracts and all other degenerative conditions associated with aging. Dr. Harmon proved that age-related immune deficiency is caused by oxidative stress — and can be reversed by antioxidants.
Antioxidants are found in a wide variety:
Antioxidant enzymes that are produced by your body, including superoxide dismutase and glutathione. In order to produce these enzymes, you need nutritional building blocks such as manganese, zinc, iron, copper and selenium; you get these from your diet.
Another way to categorize antioxidants is based on whether they are soluble in water or in fats. You require both types to protect your cells.
The interior of your cells and the fluid between them are composed mainly of water. But your cell membranes are made largely of fat. As you know, oil and water don't mix. Substances that are soluble in water are not soluble in fat, and vice versa.
The fat-soluble antioxidants (such as vitamin E) work primarily in your cell membranes, whereas the water-soluble antioxidants (like vitamin C) are present in your bodily fluids. Some antioxidants, such as lipoic acid and astaxanthin, work everywhere.
Free radicals can strike both in the watery cell contents or the fatty cellular membrane, so you need defenses for both. That's another reason to make sure you get a full complement of antioxidants in your diet.
You may have heard of a standard rating system for antioxidants called ORAC Values. This is one method that has been used to assess the antioxidant capacity of different foods. However, ORAC standards only apply to water-soluble antioxidants — not fat-soluble ones. This makes it useless in comparing the strength of water-based antioxidants to fat-soluble ones.
Here are links to other pages
with more information on what are antioxidants: