Mitchell, Nicole Jean (2013-08). Human Exposure to Foodborne Toxins in Ghana: Intervention Strategy for Reduction of Aflatoxin and Fumonisin Bioavailability. Doctoral Dissertation.
Thesis
International health has typically focused on remediation of infectious diseases in developing countries. However, recent reports from the International Agency for Research on Cancer (IARC) have highlighted the importance of cancer incidence/ mortality in the developing world. Foodborne mycotoxins produced by fungi, called aflatoxin (AF) and fumonisin (FB), have been associated with hepatocellular and esophageal carcinomas among other deleterious effects, such as growth faltering and immune dysfunction. Exposure to these toxins in Ghana is particularly high due to food insecurity, climate, and lack of regulatory infrastructures. Work to alleviate AF and FB contamination in Africa has focused on instituting good agricultural and storage practices however, exposures remain inextricable in many communities. Utilization of a calcium montmorillonite clay, UPSN, shows promise of tightly binding both AF and FB in the gastrointestinal tract, thereby reducing their bioavailability. The objectives of this research were to determine exposure susceptibility in Ghana and to assess efficacy and safety of UPSN treatment within vulnerable populations. Cross-sectional data from six different regions of Ghana indicated that AF exposure is associated with maize consumption and region of residence. However, food preparation practices were not correlated to AF levels in the present study. Therefore, future intervention strategies were focused on the end point of the food consumption chain by reducing AF exposure from maize immediately prior to ingestion (i.e. UPSN treatment). In a three-month trial an encapsulated montmorillonite clay was efficacious in reducing AF exposure. However, concern for sustainability and its applicability for children led to an effort to alter the dose dissemination form. Inclusion of UPSN in common Ghanaian foods retained the efficacy of the clay, reducing a short-term biomarker (AFM_(1)) by 55%, and was determined to be safe in children (ages 3-9). Importantly, daily assessment of AFM_(1) levels was successful in providing statistical significance of intervention effects within only five days of treatment. Initial results indicate that UPSN could efficiently to bind both AF and FB in the gastrointestinal tract, reducing biomarkers for both toxins in animal models. Thus, UPSN could positively impact health in developing communities at risk for AF and FB exposure.
