The air we breathe Everyone knows that oxygen is essential for all life - the body uses it as it breaks down food and creates energy for cells. But did you know that, as well as being an absolute necessity for good health, its use in the body can also result in the production of certain unwanted by-products, called oxidants. These particles are free radicals - unstable molecules that can damage DNA and cell structure. They cause harm because they are constantly trying to stabilise by attempting to 'steal' electrons from nearby molecules. This, in turn, damages those molecules and makes them unstable too, causing them to also seek out other electrons. And so, a vicious circle is created. Free radicals and oxidants Free radicals are produced as a result of both internal (endogenous) and external (exogenous) factors. Endogenous free radicals are produced as a result of normal biological processes, like aerobic respiration, metabolism and inflammation. In contrast, exogenous free radicals are produced as a result of environmental factors. For example, pollution, sunlight, stress, UV rays, poor diet, alcohol intake, smoking, strenuous exercise and X-rays. Unfortunately, in this modern age of pollutants and toxins, both in the environment and in our food chain, levels of free radicals in our bodies are higher than ever before. It is impossible to avoid damage from free radicals, and our body's own defences against it are not foolproof. When our levels of free radicals exceed the protective capabilities of those defences, what is referred to as "oxidative stress" occurs. This means that the system is no longer able to readily detoxify or to repair the resulting damage. As time goes on, cell parts damaged by oxidation accumulate, contributing to toxic load, ageing, a strained immune system and illness. Our natural defences The human body is pretty amazing and, for the most part, its complex processes run smoothly. However, like everything else, it eventually comes under strain and can even break down, especially as we age, and physical ailments can start to crop up. The key is to provide our bodies with as much nutritional support as we can, so that it can fuel its own natural defences. The body's primary defence against free radical damage is antioxidants - substances that help counteract the damaging effects of oxidation in tissue. Antioxidants Antioxidants are nutrients (vitamins, minerals, carotenoids, polyphenols and other phyto-chemicals), as well as enzymes (proteins in the body that assist in chemical reactions). While it is not entirely clear how antioxidants work, their most important characteristic in terms of supporting the body against free radicals is that they are stable with or without the extra electron, so they can help to stop the chain reaction referred to above. Antioxidant foods Antioxidants are present in many natural, whole foods (such as fruit and vegetables). In many cases, it is possible to identify antioxidant-rich sources through their distinctively bright colours. For instance, the deep red of cherries; the deep purple of beetroot; the bright orange of carrots; the yellow of turmeric; and the blue-purple of blueberries, blackberries and grapes. Vitamin C and vitamin E are two of the most potent antioxidants found in nature, present in high levels in foods such as parsley, rosehips, elderberries, blackcurrants, citrus fruits, broccoli, nuts and whole grains (oatmeal, rye, barley). Foods that have exceptionally high levels of antioxidants are often referred to as "superfoods" or "superfruits", for that reason. For example, green tea, acai berries and wheatgrass. Supporting your antioxidant levels Our bodies produce metabolic enzymes that are extremely effective antioxidants. However the body's ability to produce these enzymes drops significantly in our late twenties. Similarly, if your lifestyle is conducive to high levels of free radical production, it is a good idea to support your antioxidant levels through external (dietary) sources. Eating a balanced diet, rich in a variety of seasonal (preferably organic) fruits, vegetables, green leafy plants and whole grains, is one of the best ways to support your body's antioxidant levels. However, if you feel that you need additional support, a more concentrated intake, or a more convenient and reliable source, food-based antioxidant supplements can be the perfect solution.