Are you eating genetically modified food?

2012-11-06 07:03

Andreas Späth

Are you consuming food made using genetically modified (GM) crops? You probably are, even if you're not aware of it.

The Washington-based Environmental Working Group recently conducted an interesting investigation. Using 2011 data provided by the US Department of Agriculture, they estimated that average Americans consume more than their body weight – 193 pounds or about 87.5 kg – in GM food every year.

The South African government along with much of our agriculture industry has been as enthusiastic about genetic engineering as their US counterparts. This remains the only country in the world that allows GM varieties of its national staple food – white maize – to be grown commercially. In the 2011/2012 season approximately 72% of all maize seed sold in South Africa was GM.

So, unless you’re extremely vigilant or on an organic-only diet, chances are pretty good that you are eating your share of GM food on a regular basis, since maize and its by-products find their way into a surprisingly wide variety of food.

Exactly what the human health implications are remains a very controversial topic. In September, a French study published in a peer-reviewed scientific journal argued that rats fed on GM maize and exposed to Monsanto’s Roundup, a glyphosate herbicide which is routinely sprayed on this maize, increased the rate of premature death in the animals compared to control groups.

They also claimed a significantly raised incidence of cancerous tumours and severe kidney and liver damage. The variety of maize used, Monsanto’s NK603, has been approved in South Africa since 2002 and is extensively planted as yellow and white maize.

As soon as it was released, the study was simultaneously embraced by GM critics and branded as inadequate and deeply flawed by pundits of the technology. What remains a fact, however, is that precious little independent, large-scale and long-term research into the human health effects of GM crops has ever been conducted anywhere. We continue to be our own guinea pigs in this area.

The detrimental environmental impact of GM crops is less contentious. For years, one of the biotech industry’s main selling points has been the promise that GM crops would reduce the use of toxic pesticides.

Some GM crop varieties are engineered to release their own insecticide, supposedly reducing the need for farmers to apply synthetic equivalents. Others GM crops are designed to be resistant to glyphosate herbicides like Roundup. In this case the idea is that limited applications of glyphosate would be sufficient to control weeds while doing no harm to the crops themselves.

There are now increasingly worrying signs, however, that nature is beating the genetic engineers at their game. In September, a paper published in the peer-reviewed journal Environmental Sciences Europe, showed that herbicide use in the USA increased by 239 million kilograms or about 11% between 1996 and 2011, because weeds are becoming increasingly resistant to glyphosate, some developing into so-called superweeds.

Statistics on pesticide use in South Africa are difficult to come by, but data from the UN show that glyphosate imports have risen from 12 million litres in 2006 to 20 million litres in 2011.

Last month also saw researchers from Iowa State University release the results of a study which indicates that western corn rootworm, an insect very destructive to maize plants, has developed resistance to Monsanto’s insecticide-producing YieldGuard variety of GM maize. In the past, this pest, which feeds exclusively on maize, was largely controlled by the age-old technique of crop rotation with farmers alternating their plantings of maize with other crops, like soybeans. As insect resistance to GM crops increases, we can expect the use of toxic insecticides to rise as well.

There is some good news for consumers who want to steer clear of GM food though. On 9 October, the Department of Trade and Industry published a draft amendment to the regulations that govern the labelling of GM food in South Africa. If it’s approved – and let’s hope it is – all imported and locally produced goods that contains 5% or more GM components or ingredients have to be labelled as "contains genetically modified ingredients or components", giving South Africans the option to choose if they want to support this technology or not.

- Andreas freelance writer with a PhD in geochemistry. Follow him on Twitter: @Andreas_Spath

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