The effect of aflatoxins and fumonisins on child growth
February 26 2016
A report by the International Agency for Research on Cancer (IARC) has highlighted the association between exposure to mycotoxins and child health problems. The report found multiple studies demonstrating adverse health effects from both aflatoxin and fumonisin exposure including child growth stunting due to these toxins.
Studies were considered which investigated the prevalence of aflatoxins and fumonisins in staple foods with biomarkers or a combination of food consumption measures and contamination levels. These methods can be used to identify the main dietary contributors to exposure, detect areas with unacceptable exposures, assess the health impacts of mycotoxins and determine the efficacy of intervention strategies. Contamination levels vary widely depending on the country of origin. Developed nations such as Europe and the United States have strict standards (ranging from 2 parts per billion to 20 parts per billion); ensuring that fields and crops are treated to reduce contamination. However, many developing countries don’t maintain the same standards, and farmers don’t have the ability or resources to treat their crops. Both aflatoxin and fumonisins are therefore present at dangerously high levels in foods such as groundnuts, cassava and corn; which together constitute the majority of children’s diets in many African countries
Also investigated was the prevalence of child stunting in developing countries, with the global prevalence of stunting in children younger than 5 years in 2011 estimated to be 26%, with large regional variation, (Africa and South-Central Asia having the highest prevalence). Stunting and other forms of undernutrition are associated with poverty, problems of food insecurity and environmental exposure to infectious agents and toxins. The authors suggest that foetal growth restriction (FGR) is a greater contributor to infant mortality and to stunted growth than previously recognised. Investigations into the causes of FGR and potential interventions are therefore imperative.
The report goes on to highlight six high-quality studies showing an association between aflatoxin/fumonisin exposure and growth impairment in humans. The studies collectively show that children with the highest toxin exposures have the smallest gains in height. For example, Gong et al., (1, 2) undertook both a longitudinal study and a cross-sectional study, and found a significant association between in-utero aflatoxin exposure and growth faltering in infants, while Kimanya and colleagues (3) found similar results with exposure to fumonisin. One critical gap in current knowledge is the causal mechanism or mechanisms for the relationship. An initial suggestion is immune system dysfunction, mediated by mycotoxin exposure, leading to growth impairment from energy loss (e.g. Bondy and Pestka, 4). Though these initial studies are small, the IARC report provides an important foundation from which further investigation can take place. Understanding the mechanism(s) will lead to all-important intervention studies tackling the global burden of disease associated with mycotoxin exposure.
Original source: Sciencemag.org
Full report: IARC
(1). Gong et al., 2002
(2). Gong et al., 2004
(4). Bondy & Pestka, 2000