Antioxidants and Free Radicals – Understanding the Relationship


After the Christmas and New Year over indulgence most people are looking to reconnect with a healthier lifestyle.  Here is an article originally published by me on that will provide some information to start your new healthier lifestyle.Antioxidant foods and antioxidant vitamins are currently hot topics. Less is known about free radicals and free radical damage.

In order to understand the health benefits of antioxidants it is important to know that they are among the major players on the first line of defence against free radical damage.


What Are Free Radicals

Free radicals are oxygen molecules that have mismatched pairs of electrons.  They can be created naturally in the body by

  • exercise
  • inflammation
  • mitochondria
  • ischemia

They are also created externally by

  • environmental toxins
  • cigarette smoke
  • ozone
  • ultraviolet light
  • drugs
  • pesticides

The lack of matched electrons cause free radicals to move about the body creating havoc as they try and steal electrons from other molecules.  Free radicals have been implicated in diseases such as

  • cancer
  • atherosclerosis
  • cataracts
  • aging
  • endothelial cell injury

Not all free radicals should be destroyed since the body uses these molecules to defend itself against pathogenic microbes however an overabundance of free radicals with too few antioxidants will cause oxidative stress which will in turn cause chronic damage to tissue.

What are Antioxidants

Antioxidants are molecules stable enough to donate an electron to a free radical and thereby neutralize it.  Antioxidants include the antioxidant vitamins e and c as well as carotenoids.  These molecules can be found in vitamins as well as certain colour rich foods, teas and dark chocolate.
Green tea benefits as antioxidants are in the news daily.  The presence of EGCG a member of the catechin family is thought to be the most beneficial component of green tea.  It has benefits against cancer, atherosclerosis and tooth decay.

Antioxidant Foods

Carotenoids are the red yellow and orange pigments in plant  foods like fruit and vegetables.  Of this group of molecules the most important appears to be b-carotene.  The body cannot produce this substance and so must ingest it from an external source.  Beta Carotene can be found in carrots, strawberries, egg yolks peppers and a number of other foods.  Low levels of b-carotene in adipose tissue has been shown in studies to be a contributing factor in myocardial infarction in people who smoke.

Treatment of various pre-cancerous lesions with b-carotene has been shown to cause these lesions to regress.  Studies have shown that b-carotene can be useful in the prevention of stomach and breast cancer.

Beta carotene supplements are available but there is controversy about whether or not they actually increase the risk of certain cancers.  By far the best way to increase b-carotene in the body is through the consumption of highly coloured vegetables and fruits.  The recommended daily amount of fruits and vegetables is 5 servings.  Whole fruits and vegetables are higher in b-carotene and other antioxidants than the juices.

Antioxidant Vitamins

Antioxidant vitamins include vitamin e and vitamin c. Vitamin c being water soluble interacts with the free radicals within the water compartment of cells as well as with the fluid between the cells.  It is considered one of the most important antioxidants for extracellular fluids.

Vitamin c generates vitamin e from its interaction with the tocopheroxyl radical.  Vitamin c is  important  for its protective effects in cancer, arthritis, coronary artery disease  (vitamin c assists in keeping vascular walls toned and functioning.) and aging.

Many studies have reported the protective effects of consuming fruit and vegetables.  These effects have been attributed to the presence and protective effects of vitamin c.

Vitamin e like b-carotene cannot be manufactured by the body and therefore must come from an external source.. Vitamin e is the principal antioxidant in the body.  It has a protective effect on polyunsaturated fatty acids in the cell membranes.  It can work at high oxygen pressures which cause free radicals to be scavenged and tissue damage to be minimized.

Vitamin e is an effective anti-aging compound.  In fact it is found in many anti-aging cosmetic formulas.  As well as its anti-aging effects vitamin e has been known to protect against cancer, ischemia, arthritis and even some neurological disorders.

It is clear that while some free radicals are needed to fight against disease most are not.  By getting 5 servings of fruit and vegetables per day a person can help to protect themselves against disease and aging.