Puts the practice of dirt eating by women into a larger context: that of dirt eating, or geophagy, in the animal kingdom and dirt eating by entire human populations, men, women and children. Presents the idea that we are all dirt eaters in that we all add salt to our diet and that dirt eating is neither an uncommon, nor an abnormal behavior, but a reflection that being a human omnivore is a tricky business in many parts of the world. Humans need forty or fifty nutrients to stay healthy, and sometimes we have to go outside the bounds of what is considered food to find them. Or, we have to add things to our diet, like clay, in order to turn toxic foods into nutritious ones.

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... Sing and Sing (2010) report how identified clays are collected, mixed with available animal fats and/or grain flours, molded into serviceable portions, and baked or left drying naturally. Pre-made soil cakes are common in local marketplaces in sub-Sahara Africa (Allport, 2002, Hunter, 1973. ...

The term geophagy is applied to the recurrent intentional eating of soil with multifactorial motivation. Geophagists are generally defined by gender (women), age (children), physical status (e.g. pregnancy, lactation, postpartum), social status (people exposed to significant nutritional deficiencies), and culture, but lost awareness of traditional medical meaning of this practice is changing these consumption patterns and increasing health risks. Moreover, although the holistic anthropological perspective recognizes soil consumption as mineral supplementation under certain circumstances, we should consider how the living environment has changed and is changing, along with diet, nutrition requirements, and habits. Therefore, benefits-to-risks ratio of cultural behaviours initiated centuries ago based on traditional medical practices requires deep revision and assessment. Knowledge on minerals metabolism, bioavailability and interactions is required to properly assess the role of geophagy in a balanced and safe intake of micronutrients. Most important, the risk of unbalanced intake of minerals may be serious since the mineralogy and chemistry of geophagic clays are uncontrolled, variable, and difficult to standardize. In addition, other factors (radioactive materials, organic chemicals and soil pathogens) complicate the risk assessment for population groups consuming soil. Since the geophagic practice is expected to persist despite economic development, the paper discusses the multifaceted spectrum of geophagy to highlight critical aspects for risk management.

... The clay mineral kaolin, which is found in some soils, has been widely used as a digestive aid. The original formula for the anti-diarrheal medicine Kaopectate was a combination of kaolin and pectin (Allport, 2002;Tobey and Covington, 1975). The formula was changed in the early 1990s when the kaolin-pectin mix was replaced by attapulgite, another soil mineral. ...

Many different fields are interested in soils and human health, including but not limited to soil science, geology, geography, anthropology, biology, agronomy, sociology, public health, and the medical profession. Individuals from many of these fields were solicited as both authors and reviewers of the chapters in this book. Due to the wide-ranging target audience, it was necessary for chapter authors to communicate useful and accurate information without getting too deep into the professional jargon of any particular field. Therefore, readers of this book will likely find that the chapters don't go as deep into their specialty areas as a publication that was written specifically for that specialty would, but our goal was to make this publication accessible and valuable to these disparate fields of study. It is our hope that the approach taken will provide useful information to all target fields while also being understandable by a professional in any of those fields. It is up to you as readers and users of this book to decide whether or not this effort was successful. Another major goal was to elucidate the current state of knowledge in soils and human health and to identify places where more work is needed. The study of soils and human health is very complex. Traditional scientific approaches that isolate a single variable and investigate that variable do not work well in the study of soils and human health because many of the issues that affect human health have complex, synergistic relationships. To truly understand soils and human health we have to gain an understanding of interactions between multiple variables. We also have to gain an understanding not only of the properties of soils and processes occurring in soils, but also of relevant properties and processes outside of the soil that influence what occurs within soil. And, of course, we have to understand how soil exposure in its many potential forms and ways influences the human organism. Going forward, the diverse array of fields with an interest in soils and human health need to have increased cross-disciplinary communication and cooperation if we are going to adequately address soil and human health issues. Complex interdisciplinary research teams will be needed with expertise in the relevant areas and the ability for the team members to communicate effectively with one another at a professional level. In a scientific world where the trend has often been ever increasing specialization and increasing difficulty communicating, in some cases, even with other discipline experts in related but separate subfields, the interdisciplinary nature of soils and human health studies presents a significant challenge going forward. Eric C. Brevik and Lynn C. Burgess Dickinson, ND March, 2012

... The clay mineral kaolin, which is found in some soils, has been widely used as a digestive aid. The original formula for the anti-diarrheal medicine Kaopectate was a combination of kaolin and pectin (Allport, 2002;Tobey and Covington, 1975). The formula was changed in the early 1990s when the kaolin-pectin mix was replaced by attapulgite, another soil mineral. ...

  • Eric C. Brevik Eric C. Brevik

Few people recognize the connection between soils and human health, even though soils are actually very important to health. Soils influence health through the nutrients taken up by plants and the animals that eat those plants, nutrients that are needed for adequate nutrition for growth and development. Soils can also act to harm human health in three major ways: i) toxic levels of substances or disease-causing organisms may enter the human food chain from the soil ii) humans can encounter pathogenic organisms through direct contact with the soil or inhaling dust from the soil, and iii) degraded soils produce nutrient-deficient foods leading to malnutrition. Soils have also been a major source of medicines. Therefore, soils form an integral link in the holistic view of human health. In this presentation, soils and their influence on human health are discussed from a broad perspective, including both direct influences of soils on health and indirect influences through things such as climate change, occupational exposure to soil amendments, and the role of soils in providing food security.

  • Thiele-Bruhn Sören Thiele-Bruhn Sören

Intact, 'healthy' soils provide indispensable ecosystem services that largely depend on the biotic activity. Soil health is connected with human health, yet, knowledge of the underlying soil functioning remains incomplete. This review highlights selected services, i.e. (i) soil as a genetic resource and hotspot of biodiversity, forming the basis for providing (ii) biochemical resources and (iii) medicinal services and goods. Soils harbour an unrivalled biodiversity of organisms, especially microorganisms. Some of the abilities of autochthonous microorganisms and their relevant enzymes serve (i) to improve natural soil functions and in particular plant growth, e.g. through beneficial plant growth-promoting, symbiotic and mycorrhizal microorganisms, (ii) to act as biopesticides, (iii) to facilitate biodegradation of pollutants for soil bioremediation and (iv) to yield enzymes or chemicals for industrial use. Soils also exert direct effects on human health. Contact with soil enriches the human microbiome, affords protection against allergies and promotes emotional well-being. Medicinally relevant are soil substrates such as loams, clays and various minerals with curative effects as well as pharmaceutically active organic chemicals like antibiotics that are formed by soil microorganisms. By contrast, irritating minerals, soil dust inhalation and misguided soil ingestion may adversely affect humans. This article is part of the theme issue 'The role of soils in delivering Nature's Contributions to People.

  • Kimberly Jamie
  • Gary Sharples Gary Sharples

While sociologists have made significant theoretical contributions to the antimicrobial resistance (AMR) debate, little attention has been given to the antimicrobial products themselves. Here we advocate a significant new direction which centers on the social and material life of antimicrobials, specifically on what they are made from and how this affects their use. This focus is timely because, in the context of declining efficacy of biomedical antibiotics, diverse materials are increasingly taking center stage in research and drug discovery as potential agents for new antimicrobial treatments. Of particular significance are natural antimicrobials, such as plants, honey and clay, whose antimicrobial potential is well-documented and which are increasingly moving into mainstream antimicrobial research. Alongside this biomedical focus, we suggest that the social and material lives of these antimicrobial materials require attention to (i) highlight the ways they have been, and continue to be, used in diverse cultures globally, (ii) explore ways we might theorize these materials within wider AMR debates, and (iii) examine the impact of antimicrobials' materiality on their use by patients. This article takes the example of clay, whose antimicrobial properties are well-established and which has been used to treat wounds and gastrointestinal problems for millennia. We first locate clay as an exemplar of a wider shift toward natural products drug discovery in pharmaceutical science and antimicrobial research. We then offer a number of theoretical "ways in" for sociologists to begin making sense of clay as it comes under the western biomedical gaze. We map these conceptual lenses on to clay's physical and symbolic mobility from its use in the global south into western biomedical research and commercialization. We particularly concentrate on post-colonial theory as a means to understand clay's movement from global south to north; laboratory studies to examine its symbolic transformation to a black-boxed antimicrobial artifact; and valuation practices as a lens to capture its movement from the margins to the mainstream. We finish by reflecting on the importance of materiality in addressing optimal use of medicines and by advocating an interdisciplinary approach to AMR which positions sociology as a key contributor to AMR solutions.

Ball clay is known to be naturally contaminated with high levels of polychlorinated di-benzo-p-dioxins (PCDDs). This study evaluated the potential for PCDD, polychlorinated dibenzofuran (PCDF) and polychlorinated biphenyl (PCB) release during the kiln firing of ball clay in an art studio. Toxic equivalence (TEQ) were calculated using World Health Organization (WHO) 2005 toxic equivalence factors (TEF) and congener concentrations. Ten bags of commercial ball clay were found to have an average TEQ of 1370nanograms/kilogram (ngkg(-1)) dry weight (dw), almost exclusively due to PCDDs (99.98% of TEQ). After firing, none of the 29 dioxin-like analytes was measured above the limits of detection (LOD) in the clay samples. Air samples were taken during firings using both low-flow and high-flow air samplers. Few low-flow air samples contained measurable levels of dioxin congeners above the LOD. The mean TEQ in the high volume air samples ranged from 0.07pgm(-3) to 0.21pgm(-3) when firing ball clay, and was 0.11pgm(-3) when no clay was fired. These concentrations are within the range measured in typical residences and well-controlled industrial settings. The congener profiles in the high-flow air samples differed from the unfired clay; the air samples had a considerable contribution to the TEQ from PCDFs and PCBs. Given that the TEQs of all air samples were very low and the profiles differed from the unfired clay, it is likely that the PCDDs in dry ball clay were destroyed during kiln firing. These results suggest that inhalation of volatilized dioxins during kiln firing of dry ball clay is an unlikely source of exposure for vocational and art ceramicists.

  • Kima Cargill

Increasingly, psychologists practicing as clinicians, researchers, and educators are concerned about nutrition, obesity, dieting, and body image. This article describes the development and teaching of an interdisciplinary undergraduate class on the Psychology of Food and Culture. I describe the course philosophy and curriculum as well as make recommendations to educators interested in developing a similar course. I also include recommendations for those who want to integrate components of this course into other psychology classes.

  • David Sing
  • Charles F. Sing

Over evolutionary time humans have developed a complex biological relationship with soils. Here we describe modes of soil exposure and their biological implications. We consider two types of soil exposure, the first being the continuous exposure to airborne soil, and the second being dietary ingestion of soils, or geophagy. It may be assumed that airborne dust and ingestion of soil have influenced the evolution of particular DNA sequences which control biological systems that enable individual organisms to take advantage of, adapt to and/or protect against exposures to soil materials. We review the potential for soil exposure as an environmental source of epigenetic signals which may influence the function of our genome in determining health and disease.

Earth samples (soils and parent materials) eaten by humans on three continents were analyzed chemically and mineralogically. Samples from Changsha county, China, are from three sites and were used as recently as the 1950s as famine food; soil from a site in North Carolina, USA was consumed for general health benefits; samples from Zimbabwe are still used as medicine for digestive problems (diarrhea). In each case, it is 'common knowledge' that the geophagy is beneficial. Chemical analysis of the soils and of soil extracts, and mineralogical analysis of the soils, reveal patterns of element levels and clay minerals relatively consistent with the effects desired or reported by consumers. There are important parallels between geophagy in humans and in animals, in particular the apparent quest for dietary/nutritional and pharmaceutical benefits.