History of soils in relation to animal and human health

What are the factors that influence animal and human health? Most people could rapidly list a number of items, most likely things like good nutrition, proper medical care, exercise, clean safe water, and so forth. Most people probably would not include soil on their list, but studies have shown that the properties of soils are actually very important to both animal and human health. This is true for many reasons, for example, soils supply many of the nutrients found in our food, serve as filters to clean the water we drink, and are a major source of medications. Soils can also expose animals and humans to pathogens or toxic levels of various elements and chemical compounds. This can happen through ingestion, inhalation, or penetration of the skin (Steffan et al. 2017). While the scientific study of the relationships between soils and animal and human health is pretty new, the idea that such relationships exist goes back to at least 1400 before common era (BCE) (Brevik and Sauer 2015). This paper will explore some of the highlights of this history and how our understanding of soil/animal-human health relationships has changed over time. It will conclude by drawing on this understanding of history to off er some perspectives on where such studies need to go as we look to the future.