Antioxidants 101

What Are Antioxidants?

As the name implies, antioxidants are substances that are capable of counteracting the damaging, but normal, effects of the physiological process of oxidation in animal tissue. Antioxidants are nutrients (vitamins and minerals) as well as enzymes (proteins in your body that assist in chemical reactions). They are believed to play a role in preventing the development of such chronic diseases as cancer, heart disease, stroke, Alzheimer's disease, Rheumatoid arthritis , and cataracts.

Oxidative stress occurs when the production of harmful molecules called free radicals is beyond the protective capability of the antioxidant defenses. Free radicals are chemically active atoms or molecular fragments that have a charge due to an excess or deficient number of electrons. Examples of free radicals are the superoxide anion, hydroxyl radical, transition metals such as iron and copper, nitric acid, and ozone. Free radicals containing oxygen, known as reactive oxygen species (ROS), are the most biologically significant free radicals. ROS include the radicals superoxide and hydroxyl radical, plus derivatives of oxygen that do not contain unpaired electrons, such as hydrogen peroxide, singlet oxygen, and hypochlorous acid.

Because they have one or more unpaired electrons, free radicals are highly unstable. They scavenge your body to grab or donate electrons, thereby damaging cells, proteins, and DNA (genetic material). The same oxidative process also causes oils to become rancid, peeled apples to turn brown, and iron to rust.

It is impossible for us to avoid damage by free radicals. Free radicals arise from sources both inside (endogenous) and outside (exogenous) our bodies. Oxidants that develop from processes within our bodies form as a result of normal aerobic respiration, metabolism, and inflammation. Exogenous free radicals form from environmental factors such as pollution, sunlight, strenuous exercise, X-rays, smoking and alcohol. Our antioxidant systems are not perfect, so as we age, cell parts damaged by oxidation accumulate.

Omega 5 oil products contain antioxidants, and so do pomegranate juice and pomegranates seed oil.

Do Antioxidants Improve Health?

Since antioxidants counteract the harmful effects of free radicals, you would think that we should consume as much as of them as possible. The truth is, although there is little doubt that antioxidants are a necessary component for good health, it is not clear if supplements should be taken and, if so, how much. Once thought to be harmless, we now know that consuming mega-doses of antioxidants can be harmful due to their potential toxicity and interactions with medications. Remember — antioxidants themselves may act as pro-oxidants at high levels.

There are several possible explanations to account for the results.

• The amount of antioxidants in supplements may be so high compared with that in the diet that it leads to a toxic effect.
• Other nutrients may be present in fruits and vegetables that work in sync with antioxidants and are necessary to provide a protective effect.
• The study participants may have been too old to start taking antioxidants, or they may have led lifestyles that were too unhealthy for the antioxidants to make a positive difference.

Furthermore, literally hundreds, if not thousands, of observational studies (where investigators look for associations without giving participants supplements to take) have linked diets rich in antioxidant-rich fruits and vegetables to a lower risk for diseases like cancer, heart disease, stroke, cataracts, Parkinson's, Alzheimer's, and arthritis. So, despite the disappointing findings of trials, scientists remain certain of the many potential benefits of dietary antioxidants — they simply haven't figured out exactly how the different antioxidant systems work together in our bodies to protect us from free-radical damage.