Aflatoxin threat in Nepal, Bangladesh

[KATHMANDU] Aflatoxin produced by the fungus aspergillus flavus — a toxic contaminant in food crops and known to cause liver cancer — prevails at unacceptably high levels in the bloodstream of pregnant women in Nepal and Bangladesh, says a new study. 

The fungus thrives on improperly stored crops such as corn, maize, wheat, rice, peanut, soya bean, and millet, especially in conditions of high humidity. In 2003, an outbreak of aflatoxin poisonings in Kenya left 120 people dead.

The randomised community study, published in the Journal of Food and Chemical Toxicology in October, measured aflatoxin exposure to mother and child during pregnancy, early infancy and at 24 months in the Sarlahi district in southern Nepal and Gaibandha district in northwest Bangladesh.

Using biomarkers — major proteins found in the bloodstream on which the contaminant gets attached — the team, led by Keith West, author and director of the Centre for Human Nutrition at Johns Hopkins Bloomberg School of Public Health, Baltimore, found levels of aflatoxin comparable to those detected during the Kenyan outbreak.

“We are looking at an exposure level that overlaps with a known high risk event that has happened in public health over the past decade,” said West during a scientific symposium in Kathmandu on collaborative research in nutrition in November.

West said it was alarming that traces of aflatoxin were found in cord blood (blood in the umbilical cord and placenta). “This is an indication that the foetus’s liver is already being exposed to and metabolising this carcinogen to noxious agents and secreting it into the bloodstream so it can be picked up in the cord blood.”  

Trials conducted in Benin, West Africa, have shown that aflatoxin contamination in the food system can be reduced by 60 per cent by simple methods such as removing contaminated grains and sun drying, West said.

Such post-harvest interventions are yet to be initiated in Nepal or Bangladesh. “We have not worked on intervention as yet. We are at the project development stage for research at the farmers’ level,” Krishna Prasad Rai, an officer at Nepal’s Central Food Laboratory, Department of Food Technology and Quality Control told SciDev.Net.

Mohammed Miaruddin, chief scientific officer at the Bangladesh Agricultural Research Institute, tells SciDev.Net that while the threat from aflatoxin is not seen as big his organisation “recommends raising of awareness on crop preservation since moisture is a big factor in Bangladesh.” 

The study continues to search for links between aflatoxin exposure and stunting in children. “But even as we evaluate and try to make sense of early life consequences, we can be assured that there are problems in the chronically aflatoxin exposed adult population with respect to cancer risk,” West said.

> Link to abstract in Journal of Food and Chemical Toxicology

This article has been produced by SciDev.Net's South Asia desk.