Food and medicines in the Mediterranean tradition. A systematic analysis of the earliest extant body of textual evidence

Ethnopharmacological relevance The relationship between food and medicines has long been investigated and is of crucial importance for the understanding of the development of ethnopharmacological knowledge through time. Hippocrates, considered the Father of Medicine, is credited with an aphorism equating food and medicine. No inquiry has been performed, however, into the collection of texts attributed to Hippocrates and, going beyond, into this statement, which is generally accepted without further examination. A clarification is much needed as the question of the relationship between food and medicines as potent substances are crucial to ethnopharmacology. Materials and methods To verify the validity (if not the authenticity) of the theory on the identity of food and medicine attributed to Hippocrates, we digitized the whole collection of texts ascribed to Hippocrates in the original Greek language (the so-called Hippocratic Collection), which date back from the age of Hippocrates (late 5th century and 4th century BCE) to a more recent time (2nd century CE). On this basis, we extracted and databased all the information related to remedial therapy, that is, their materia medica (vegetable, animal and mineral) and their use(s). We identified both the plant species according to modern up-to-date taxonomy and the medical conditions as precisely as possible. We then screened these plants to discover what their uses were and, going backward in time, we examined (when possible) their native distribution, domestication, possible introduction (in the case of non-native species) and cultivation to determine whether these species had been known for a long time and might have been the object of long-term observation as both foodstuffs and medicines. Results Tabulated data from the Hippocratic Collection revealed that 40% of the remedies in the Collection are made out of only 44 plants. Of this group, 33 species (=75% of the group) were also used for nutritional purposes in Antiquity. Domestication history of these species indicates that humans have long been in contact with them, something that the medical uses of these species confirm, as they are multiple and finely distinguished. A pilot analysis of archeological remains of medicines confirms that textual evidence corresponds to physical evidence, that is, to the practice of medicine. As a consequence, textual information can be accepted as reflecting actual practice. Conclusions Although the pseudo-aphorism according to which food are medicines and medicines are food does not appear as such in the Hippocratic Collection, it aptly expresses a fundamental element of the Hippocratic approach to therapeutics, without being, however, a creation of neither Hippocrates nor his followers and the physicians who practiced a form of medicine in the way of Hippocrates. A vast majority of the core group of plant species used for the preparation of medicines were also consumed as foodstuff. Knowledge and use of these plants probably resulted from a long co-existence in the same environment and also from multiple experiences of trial and error over millennia, whose results accumulated over time and contributed to the formation of the Mediterranean medical tradition.