Human Geophagia, Calabash Chalk and Undongo: Mineral Element Nutritional Implications

Abstract

The prime aim of our work is to report and comment on the bioaccessible concentrations – i.e., the soluble content of chemical elements in the gastrointestinal environment that is available for absorption – of a number of essential mineral nutrients and potentially harmful elements (PHEs) associated with the deliberate ingestion of African geophagical materials, namely Calabash chalk and Undongo. The pseudo-total concentrations of 13 mineral nutrients/PHEs were quantified following a nitric-perchloric acid digestion of nine different Calabash chalk samples, and bioaccessible contents of eight of these chemical elements were determined in simulated saliva/gastric and intestinal solutions obtained via use of the Fed ORganic Estimation human Simulation Test (FOREhST) in vitro procedure. The Calabash chalk pseudo-total content of the chemical elements is often below what may be regarded as average for soils/shales, and no concentration is excessively high. The in vitro leachate solutions had concentrations that were often lower than those of the blanks used in our experimental procedure, indicative of effective adsorption: lead, a PHE about which concern has been previously raised in connection with the consumption of Calabash chalk, was one such chemical element where this was evident. However, some concentrations in the leachate solutions are suggestive that Calabash chalk can be a source of chemical elements to humans in bioaccessible form, although generally the materials appear to be only a modest supplier: this applies even to iron, a mineral nutrient that has often been linked to the benefits of geophagia in previous academic literature. Our investigations indicate that at the reported rates of ingestion, Calabash chalk on the whole is not an important source of mineral nutrients or PHEs to humans. Similarly, although Undongo contains elevated pseudo-total concentrations of chromium and nickel, this soil is not a significant source to humans for any of the bioaccessible elements investigated.

High Prevalence of Opaline Silica in Urinary Stones From Burkina Faso

“…The material preferentially ingested by geophagists is clay. Its ability to form colloids and to adsorb and exchange ions while interacting with the food bolus and the digestive mucosa results in both beneficial and harmful effects [27,28,29]. Clays are used in traditional medicine for rheumatologic pains, skin infections, anaemia, gynaecologic problems or during pregnancy.…”

Géophagie associée à une anémie sévère chez la femme non gravide : à propos de 12 cas

“…Les caractéristiques des patients de notre série sont concordantes avec les cas déjà rapportés concernant l'âge [1][2][3][4][5]9], avec des observations de patients relativement jeunes (15 à 25 ans). Par contre, contrairement à Lar et al [10] qui rapportait que plus de 90 % de femmes n'avaient pas atteint le niveau secondaire, 8 sur les 12 patientes de notre série étaient scolarisées dont 5 ayant atteint au moins le secondaire.…”

“…Dans la littérature, elle concerne surtout les enfants et la femme enceinte en Afrique Sub-Saharienne [3]. Malgré son rôle supposé dans le renforcement de la barrière digestive face aux toxines alimentaires, le complexe colloïde (argile, bol alimentaire et muqueuse) met en péril l'équilibre alimentaire des géophages en faveur d'une diminution ou d'une augmentation de la biodisponibilité intestinale de certains minéraux (fer, plomb, zinc, cuivre, arsenic, calcium, magnésium, manganèse, chrome, nickel, potassium, sodium) variable selon le pays, le type d'argile consommée au sein d'un même pays et la quantité ingérée [4][5][6]. Concernant son origine, il existe toujours une controverse sur la géophagie comme cause ou comme conséquence de la carence martiale.…”

Potentially Harmful Elements in Urban Soils

“…Several reports have been published concerning this particular topic. For example, the study of Abrahams et al (2013) on the bioavailability of PHEs in two African geophagical materials, Calabash chalk and Undongo, which are commonly used in Nigeria and among the emigrants in different parts of the world, showed that the consumption of these clay soil material does not substantially contribute to PHEs' intake, nor to a better Fe uptake, one of the primary reasons for the geophagy. Conversely, Al-Rmalli et al (2010) showed that a type of clay, sikor, commonly consumed by Bangladeshi women in Bangladesh and in the United Kingdom, especially during pregnancy, may be an important source of As, Cd and Pb intake.…”