Mouldy maize could cause cancer

Maize may have a contaminant that could cause cancer and other diseases in humans and animals.

The trouble is caused by fumonisin b1, produced by fungi, according to the Hyderabad-based National Institute of Nutrition. Fumonisin b1 has already been classified by the International Agency for Research on Cancer as ''possibly carcinogenic''.

The NIN study found that high levels of fumonisin b1 found in mouldy maize and sorghum were responsible for the outbreak of an ''acute disease'' in parts of Andhra Pradesh and Karnataka recently.

Leader of the NIN study group, Dr Ramesh V Bhat, said fumonisins occurred naturally in maize and maize-based animal feed in levels ranging from a few nanograms to a few hundred micrograms. In general, maize and its products meant for animal consumption contained higher levels of fumonisin b1.

Though it is known for a long time that consumption of fungus-infected maize causes health hazards in human beings and animals, the toxin responsible for these effects was not identified till the discovery of fumonisins in 1988 by researchers from the South African Medical Research Council.

Dr Bhat said the two major diseases associated with fumonisins were the fatal degeneration of the brain's white matter in horses and pulmonary oedema in pigs. These diseases struck the Deccan plateau in October 1996, when rain-soaked maize and sorghum were consumed. Following this, death of domestic animals and outbreak of an acute disease in humans was reported.

A survey conducted in 50 villages in six districts of Andhra Pradesh and Karnataka showed that the affected humans knew that their abdominal pain and diarrhoea were caused by the mouldy grains. However, they continued eating them as the problem was not life-threatening. Besides, they had no alternate source of food.

The disease was characterised by black, sticky diarrhoea, loss of weight, lameness and mortality. Antibiotics and vitamin supplements had no effect. Feed withdrawal reduced the damage done.

Fumonisins have also been associated with the high incidence of human oesophageal cancer in certain parts of the world, including South Africa and China. But no fumonisins were found in Assam, which has the highest incidence of human oesophageal cancer in the world.

Dr Bhat said the cancer in Assam might be caused by a special food ingredient called kalakhar, a highly alkaline liquid made from banana stem.