Talk of potential benefits of antioxidants in foods such as acai berries and kale has led to the term "superfoods". Searching the web for this returns more than 39.3million hits (more than twice as many as for "Chuck Norris").

Antioxidants is a general term for a group of substances that prevent oxidation, or oxidative damage, caused by "free radicals". The levels of free radicals in our body are well tolerated under normal conditions. Nevertheless, some of our bad habits such as smoking and food choices can increase their production, therefore increasing the risk of diseases such as Alzheimer's and cardiovascular disease.

Plants are our major source of antioxidants. The amount and type varies with the plant (legumes, fruits or vegetables) and these are influenced by climate, ripening, processing and storage. There are well over a thousand types of antioxidants and famous ones include carotenoids, vitamin C and vitamin E. The rise of interest in antioxidants started in the early 1990s when researchers were at the beginning of understanding how cellular processes relate to the development of chronic conditions such as atherosclerosis and cancer. Studies showed people with low consumption of antioxidant-rich fruit and vegetables had higher chances of developing such conditions. Clinical trials looked at the effects of individual and relatively pure antioxidants. Before these trials were even finished, the health industry began promoting the benefits in foods and supplements. Since then, numerous clinical trials have shown mixed results but the industry has skyrocketed.

The benefits of "pure" (or a mixture of) antioxidant supplements is yet to be established. Controversially, some studies have shown that high doses of antioxidants can actually increase the risk of cancers and other diseases. The negative effects of antioxidant-rich supplements have also been described in relatively healthy individuals as well.

It is important to emphasise that consumption of a particular food with a significant quantity of antioxidants does not necessarily protect you from cancer or any other chronic disease.

Response by: Caroline Gouws, PhD Candidate and Dr Nenad Naumovski, Discipline of Nutrition and Dietetics, University of Canberra

Brought to you by the Fuzzy Logic science show, 11am Sundays on 2XX 98.3FM. Send your questions to askfuzzy@zoho.com