Absorption, metabolism and excretion of phenols derived from olive products.

The ageing population of many societies has been accompanied by an increase in the incidence of chronic diseases. At the same time, people are more interested in healthy dietary patterns and the use of dietary supplements. It is in this context that olive oil and olive leaf have attracted attention. Both products contain a number of biophenols that have been associated with bioactivity and positive health outcomes. Data indicate that the phenols are absorbed and metabolised and that a minor fraction of the ingested dose is excreted in the urine. This is a necessary pre-requisite to biological activity. However, their metabolic fate remains controversial. The outcomes of in vivo human studies are examined and contrasted with in vitro and animal studies. Furthermore, whether the bioactivity translates into physiological outcomes has not been established conclusively and will depend on development of suitable biomarkers of functionality.