Because the immune system is critically dependent on accurate cell-cell communication in order to mount a response, immune cell integrity is essential. Antioxidant nutrients help to maintain this integrity, reducing the damage caused by reactive oxygen species to cell membranes and their associated receptors, as well as modulating immune cell function by influencing the activity of redox-sensitive transcription factors and the production of cytokines and PGs. The effects of antioxidants appear to be particularly beneficial during periods of oxidative stress, whether the periods are acute, such as during infections, or chronic, such as in the elderly. However, the results of the prospective studies with p-carotene in smokers show that caution must still be taken in making recommendations regarding the taking of supplements that provide a greater intake than can be achieved by eating a diet rich in fruits and vegetables. In this regard, it is important to remember that the strongest evidence supporting a beneficial effect of antioxidant nutrients in reducing the risk of developing chronic oxidative stress-related disorders has come from epidemiological studies of populations consuming whole foods and not from supplementation studies. Further research needs to be undertaken to examine the interaction between different antioxidant nutrients and to establish the levels of intake required to optimize immune responsiveness in different sectors of the population (e.g. the elderly, cigarette smokers). In addition, greater emphasis should be placed on studying the effects of enriching the diet with antioxidants via real foodstuffs rather than by supplementation, since these foods undoubtedly contain beneficial compounds that we have still to discover.
Was this article helpful?