Slum children may be exposed to fungi toxin from food

Some children living in urban slums in Bangladesh may experience longtime exposure to certain toxins produced by fungi that grow over food and contaminate food grains, suggests a new icddr,b study.

Toxin grown in crops may be present in some processed foods. Photo: GMB Akash / icddr,b

The poisonous element known as ‘Aflatoxin’ is produced by a group of fungi, which can contaminate crops in the field or at harvest or during storage in warm and humid conditions.

The study, in collaboration with Johns Hopkins University, University of Virginia, University of Venda and supported by the Global Health Program of Bill and Melinda Gates Foundation (BMGF), has analysed data from the BMGF-supported MAL-ED (Etiology, Risk Factors and Interactions of Enteric Infections and Malnutrition and the Consequences for Child Health and Development) multi-country study spanning over three continents.

“Our evidence suggests that some slum children were exposed to aflatoxin over a longer period. We are yet to determine whether they are at any higher health risk from this exposure in comparison with non-slum children,” says Dr Mustafa Mahfuz, associate scientist at icddr,b and principal investigator of the study published in Nature Journal of Exposure Science & Environmental Epidemiology.

The icddr,b study is the first-of-its-kind to have examined aflatoxin exposure over a period of three years in more than 200 children in Mirpur slum settlements. Around 62% of these children were more likely to be exposed to the toxin by the time they were three years old.

“Occasional exposure to Aflatoxin, unlike long-term aflatoxin poisoning, may not cause major health problems. However, given the opportunity of long-exposure, certain types of Aflatoxin bind with other elements in the body and these remnants may lead to health risks,” explains Dr Mahfuz.

Long-term contact with certain aflatoxins are associated with growth faltering in children and heightened risk of liver cancer, notes National Cancer Institute at the National Institutes of Health (NIH).

Researchers will explore whether toxin intake and stunting are related. Photo: Shumon Ahmed / icddr,b

icddr,b researchers are looking for more insights into whether aflatoxin is associated with stunting in urban slums but this requires extensive toxin detection mechanisms. They have already assessed several aflatoxin detection methods, according to findings published in Toxin Reviews, to ascertain the most appropriate and feasible method for a developing world setting.


Why Aflatoxin is relevant to the slum children

Existing studies especially those conducted in Sub-Saharan Africa have indicated similar findings, that aflatoxin causes growth faltering in children, notes the icddr,b study.

Dr Tahmeed Ahmed, senior director of icddr,b nutrition and clinical sciences division, have conducted decades of research on growth faltering and malnutrition in Bangladesh. Children living in urban slums are among those most likely to suffer from many nutritional deficiencies, especially stunting.

“We were interested to examine whether any environmental toxin is partly responsible for the persistently high prevalence of stunting among the children in urban slums,” observes Dr Tahmeed, also senior author of the icddr,b study.

A view of an urban slum in Dhaka. Photo: Shumon Ahmed / icddr,b

Moreover the slum-setting in Bangladesh provides an ideal context for aflatoxin exposure. The fungi that produce aflatoxin is found more frequently in places with a wet environment caused by heavy rainfalls and in places with food and food grain storage problems.

The study also found that chronic aflatoxin exposure is linked to children who started consuming family food once they were no longer exclusively breastfeeding. These indications provide evidence that some children may have long-exposure to the environmental toxin, and this warrants further investigation as to how it may affect their health.

Muhamamd Zahir Hassan Nabil