Ecological, biomedical and epidemiological approaches to understanding oxidative balance and ageing: what they can teach each other

1. Oxidative stress and antioxidants have been studied in a number of disciplines, but these disciplines have not always been informed by each other’s work. 2. Here, we discuss the strengths and weaknesses of oxidative stress and antioxidant research in the areas of (i) ecology, (ii) ageing research, (iii) epidemiology, and (iv) physiology of model organisms, with an emphasis on what ecologists can learn from and bring to other fields. 3. We find that physiologists provide an essential role in clarifying basic mechanisms, but that many of their findings are context-dependent. Ecologists and epidemiologists bring strengths in understanding the relevance of context, whether it is across species, environments, or diets. Ageing research has helped to provide a clear theoretical framework for all fields and has thus spurred much of the research to date. 4. Comprehensive understanding of the complexity of oxidative balance systems will rely on integration of knowledge of physiological pathways from studies of model organisms, knowledge of long-term interactions of many parameters from epidemiological studies, and knowledge of specificity and generality of results across species and conditions as gleaned from ecological studies. 5. Studies of ageing have helped to show that all fields of antioxidant ⁄oxidative stress research should focus not on individual markers of oxidative damage or antioxidant status, but on how they integrate into oxidative balance systems. Free radicals can have beneficial roles in signalling as well as causing damage and should not be interpreted out of context.