Evolutionary Medicine: Incorporating Evolutionary Theory on the Formation of Brazilian Health Professionals

ABSTRACT The aim of this paper is to introduce some principles of Evolutionary Medicine to the community of medical educators in Brazil. Evolutionary Medicine can be defined as the application of the theory of evolution through natural selection to the understanding of human health problems. This innovative approach provides the medical field with a theoretical framework which contributes to the explanation of a great variety of serious disorders. Evolutionary Medicine, which dates back to the early 1960s, aims to explain diseases based both on recent physiological causes — those most commonly addressed by medicine — and on more distant evolutionary causes — those responsible for the emergence and survival of useful and functional biological structures throughout the history of the planet. Evolutionary Medicine rests on the assumption that functional biological characteristics are the result of evolutionary adaptive processes. Therefore, it is possible to analyze a great number of diseases in terms of adaptive vulnerabilities connected to our phylogenetic inheritance, such as human bodily inadequacies in relation to the modern environment. Besides presenting a definition of Evolutionary Medicine, this paper discusses two health problems recently dealt with in the light of the theory of evolution through natural selection. First, we discuss how the appearance, the ethnic and geographic distribution of lactose intolerance (and, on the other hand, the persistence of lactase) can only be understood taking our species’ recent evolutionary history (including its cultural transformations) into consideration. The limitations faced by previous explanations, which lacked evolutionary causes — are discussed. Secondly, the paper discusses herniated spinal disc, trying to demonstrate the link between this condition and the adaptation problems that bipedal posture may entail in view of the demands of modern lifestyle. The understanding of such problems of adaptation, combined with restrictions to natural selection pressures when adjusting a quadruped structure to a biped lifestyle, serve as the basis for the development of specific concepts used to formulate a hypothesis with relevant diagnostic potential. Finally, the paper describes ways in which medical students could incorporate this relatively new knowledge into their education.