Hi-tech crops are bad for the brain

"Miracle" crops, hailed as the answer to global famine, are contributing to widespread brain impairment in the developing world, a new report concludes.

"Miracle" crops, hailed as the answer to global famine, are contributing to widespread brain impairment in the developing world, a new report concludes.

It says that the high-yielding rice and wheat varieties that brought about the much-heralded "Green Revolution" are among a range of environmental factors undermining human intelligence.

The study, which looks at environmental threats to human intelligence, is part of the £15m Global Environmental Change Programme, financed by Britain's Economic and Social Research Council. It is published tomorrow.

It concludes that a deadly combination of soil erosion, pollution and inadequate diet is affecting the intelligence of millions of people, with effects ranging from severe intellectual disabilities to "sub-clinical decline" in whole populations.

The Green Revolution crops, introduced in the late 1960s and early 1970s, produce several times as much grain as the traditional varieties they replaced, and they spread rapidly. They enabled India to double its wheat crop in seven years, dramatically increasing food supplies and averting widely predicted famine.

But the report says that the new crops, unlike their predecessors, fail to take up minerals such as iron and zinc from the soil. So even as people consumed more calories, their intake of these key "micronutrients" fell. "High-yielding Green Revolution crops were introduced in poorer countries to overcome famine," the report says. "But these are now blamed for causing intellectual deficits, because they do not take up essential micronutrients."

The report is written by Dr Christopher Williams, a research fellow with the Global Environmental Change Programme. Using already published UN data he has calculated that 1.5 billion people - one quarter of the earth's population - are affected by "Green Revolution iron deficiency". He claims the condition impairs the learning ability of more than half of India's schoolchildren.

He concludes that, eventually, the evolution of the brain could go into reverse as humans develop more extensive digestive systems to cope with the lack of nutrients - sacrificing intelligence in the process.

The professor's sources include the Food and Agriculture Organisation of the United Nations which has compiled evidence that the amount of the metal in people's diets fell throughout most of the Third World in the 1970s and 1980s, making iron deficiency the only form of malnutrition to increase over the two decades. The greatest drops in the intake of iron took place in South and South East Asia, the very areas where the Green Revolution was most successful.

Other UN figures show that half the world's pregnant women are anaemic, because they have too little iron, putting both them and their babies at risk. The condition is thought to be responsible for 200,000 deaths a year. And the World Bank reckons that deficiencies of iron, iodine, and vitamin A together wipe out some 5 per cent of the GDP of developing countries, a crippling blow to poor economies.