There has been an upsurge in Medical Geology research in Africa during the last decade, driven by the increased realisation of the criticality of the optimal intake levels of nutritional elements and the need for elimination of potentially toxic elements PTEs) from the food chain for maintaining health. The studies have focussed on understanding the geochemical fluxes of both nutritional and PTEs in the groundwater-soil-food crop continuum, that largely define the nutritional quality of the African diet, and hence the correct balance of micronutrients and vitamins in metabolic processes. Geochemical processes carried to extremes in humid and sub-humid sectors of Africa’s surface environment have led to the evolution of large areas of the Continent that are deficient in some key nutritional elements and other areas that have high amounts of PTEs. We highlight in this review, studies that speak to the criticality of the intake levels of nutritional elements; in particular, the amount that reaches the metabolic centres of activity, which in turn, is determined by geochemobiological parameters such as bioavailability, bioaccessibility and dose-reponse relationships. It is this amount of the element (nutritional or PTE) that determines whether nutritional benefit is realised, or disease is produced. Gaps in knowledge (italicised) regarding optimal intake levels of certain nutritional elements have been identified, illnesses due to excessive intake levels of PTEs are referred, and ways of obviating the resulting maladies are predicated.