Breath alkanes as an index of lipid peroxidation

Formation of free radicals and lipid peroxidation are mechanisms that are involved in many conditions including cellular damage. In a human body, there are many antioxidant systems likely to limit the production of free radicals and to reduce their deleterious effect. The peroxidation of polyunsaturated fatty acids, such as linoleic acid and linolenic acid which are cell membrane components, induces the formation of volatile alkanes that are excreted in the breath. The determination of breath alkanes (pentane and ethane) is considered to be a valuable and elegant method to assess lipid peroxidation. The method for collecting a breath sample and the chromatographic analysis of the collected gas require a strict methodology. Moreover, we must take into consideration some factors, such as the hepatic function, which may influence the pentane metabolism itself. We critically describe the results of breath alkane determination obtained in humans in different clinical conditions.