Fail to ensure that your diet is adequate in anti-oxidants and you're asking for your body to be attacked by free radicals. And the potential severity of this attack should not be underestimated, because free radicals are strongly implicated in the aging and degeneration of our cells and therefore of our bodies as a whole.

If you're at all interested in diet and nutrition you've probably heard of free radicals and gathered that they're regarded as highly damaging. You may also be aware of research suggesting that so-called "anti-oxidant" foods (sometimes referred to as "superfoods") and supplements may play a useful role in counteracting the effects of these free radicals.

But what exactly are free radicals and anti-oxidants, and how do they do what they do within the body?

To provide a detailed explanation would probably require a PhD in molecular biochemistry, but the basics appear to be as follows.

Every cell in the body is comprised of molecules, which are in turn comprised of atoms. Each atom is made up of a nucleus surrounded by layers of electrons and it is the electrons in the outermost layer which form stable molecules by bonding with the electrons of other atoms. Free radicals are formed, however, when normal metabolic reactions within cells sometimes leave some of these electrons unbonded and their molecules thereby destabilised.

This is a perfectly normal and natural process, and free radicals may even serve a useful purpose in helping the body's immune system to counteract threats such as viruses and bacteria. Normally the body can in any case handle free radicals, but problems can arise if they're produced in excessive quantities or if insufficient anti-oxidants are present. If left unchecked, free radicals multiply themselves through chain reactions which can rapidly lead to cellular damage and ultimately even disease. The importance of anti-oxidants is that they seem to counteract the effects of free radicals by using their own electrons to bond with and stabilise them.

The problem for us in the twenty-first century is that our environment seems as though it might have been expressly designed to encourage our bodies to produce free radicals. Modern pollutants such as industrial emissions, car exhausts, pesticides, herbicides, dyes and all kinds of everyday household chemicals expose us to ever greater quantities of toxins. An unwelcome by product of its increasingly desperate struggle to detoxify the body is that the liver produces enormous numbers of free radicals.

And all of this is happening just when our diets have never been more deficient in the anti-oxidant nutrients which are most vital for the manufacture of the free radical destroying anti-oxidant enzymes. Most important of all these nutrients are vitamin C, mostly found in fresh fruits and vegetables; and Vitamin E, principally found in whole grains, nuts and certain natural oils. But the modern prevalence of highly refined grains, and the treatment of fruits and vegetables with preservatives, dyes, pesticides and even radiation is a proven disaster for the retention of these vitamins in their natural food sources.

Despite this, many physicians nevertheless continue to insist that a balanced and varied diet including all the main food groups should generally provide adequate nourishment, including anti-oxidants. And in a sense of course they're right. In an ideal world if everybody ate three well balanced meals a day, including an abundance of fresh fruit and vegetables, there might indeed be no need for supplementation. But of course, very few of us do eat like that these days.

It's been reported for example that some 25% of all Americans obtain only around 40mg of Vitamin C from their daily food intake – and that's only 2/3rds of a recommended amount which many authorities regard as in any case far too low. Likewise, the principal food sources of vitamin E make it very difficult indeed to obtain an adequate supply from food alone.

Although the body functions holistically, and needs an adequate supply of a full range of vitamins and minerals if it's to produce a good supply of anti-oxidants, any deficiency in vitamins C or E is particularly serious. Numerous studies have credited both these vitamins with excellent protective effects against the characteristic degenerative diseases associated with excessive free radical activity – including diseases of the heart and circulatory system, age-related cognitive and visual impairment, and even cancer.

Not surprisingly, then, many well informed individuals, including many physicians, take the view that supplementation of their diets with these vital nutrients is a highly sensible precaution.