Antioxidants - Our Guard Against Free Radicals

Antioxidants are substances that can defend our body from free radicals. Free radicals are compounds with uneven number of electrons, making these compounds very unstable and reactive. When the free radical molecule comes in contact with a stable molecule, it either gains or loses electrons to achieve a more stable form. In the process, the electron balance of the stable molecule is disturbed and the stable molecule becomes a free radical itself. This starts a chain reaction of destruction. Free radicals damage DNA, protein, and fats, causing many degenerative diseases such as aging, cardiovascular diseases, immune dysfunction and cancer.

Free radicals are produced by different means, including external and internal factors. External factors such as radiation, UV, environmental pollutants, cigarette smoke, bad diet (frying foods) produce free radicals in our body. Normal body functions (internal factors) such as immune cell activity and respiration also produce free radicals.

There are several kinds of free radicals, the superoxide radicals, hydroxyl radicals, peroxyl radicals and alkoxyl radicals. Recently, all of these free radicals together with hydrogen peroxide and oxygen are collectively called reactive oxygen species (ROS). Out of these free radicals, the hydroxyl radicals are the most damaging to our body.

Antioxidants are free radical scavengers. They work by donating their electrons to free radicals, restoring stability to these molecules. Antioxidants can also donate electrons to DNA or fatty acids that have lost an electron, thus neutralizing the effect of free radical damage.There are several types of antioxidants, some are produced naturally in our body, and others can be obtained from diet. These include antioxidant enzymes, vitamins and minerals, and some biochemical compounds.

Superoxide dismutase (SOD), catalase and glutathione peroxidase are antioxidant enzymes synthesized in our body. They work with other antioxidants, glutathione, proteins and uric acid, to provide a self defense against free radicals.

Vitamins A, C & E are well known antioxidants but they can convert to weak free radicals themselves once they donate their electrons to other free radicals. In contrast, antioxidant enzymes can convert free radicals to other less harmful forms or even inert and useful compounds without becoming free radicals themselves. Minerals like zinc and selenium are not antioxidants themselves, but important integral components of antioxidant enzymes, so they also play an important role in free radical defense.

Other biochemical compounds including flavonoids and nonflavonoid phenolic compounds are also strong antioxidants. Some common ones include proanthocyanidins, epicatehin, resveratrol, curcumin, silybin, etc. These compounds are abundant in kitchen spices, fruits, vegetables and herbs such as garlic, ginger, curry, parsley, rosemary, cherry, blueberry, strawberry, blackberry, black currant, grape, pomegranate, tomato, broccoli, kale, cabbage, green tea, gingko, milk thistle, hawthorn berry, etc.

Since our body is bombarded by tons of free radicals each day, we need an amply supply of antioxidants for defense. To accomplish this, we need to maintain a healthy lifestyle. Avoiding excess exposure to UV, staying away from radiation and cigarettes, consuming less oxidized fatty food can help us to reduce our exposure to free radicals. On the other hand, eating a lot of fresh fruits, vegetables, drinking green teas, using kitchen spices in cooking, and taking some antioxidant supplements can replenish the supply constantly.