Photo of researchers with genetically modified corn
Genetically modified food has caused illness in many animal species, why should humans be the exception?

Where’s the proof that GM food is safe to eat?

2 July, 2012

People eat it, animals eat it, but just how ‘safe’ is safe when it comes to GM foods?

Globally our exposure to GM organisms via food is unquantifiable. In the UK you can’t buy GM foods in the supermarket, but conventionally reared livestock are largely reared on GM feed. As the recent news story that biotech giant Syngenta hid data that proved its Bt176 maize could be lethal to livestock shows, we can’t trust the GM companies to be honest about the potential damage being done to our health.

Recently a GM pathogen new to science has been found that could well be in Roundup Ready GM soybean and corn that may be responsible for high rates of infertility and spontaneous abortions in livestock.

Does that reassure you – or make you wonder what else we don’t know about the risks of eating (and growing) GM food?

Where’s the evidence?

In America GM is more widely consumed in the form of food additives, as an unintentional contaminant in non-GM food and in animal feed. Monitoring of the global food system, however, is poor making it impossible to guarantee that conventional crops have not been contaminated to some degree by pollen drifting from fields of genetically modified crops or by being carelessly mixed together during storage.

The fact that we may all already be eating GM food to some degree, and have been for some years, is the core of the ‘safety’ argument put forward by big biotech and the government – although this is hardly grounded in sound science.

In any other field we would base our understanding of the safety of a thing in part on human studies. There would be toxicological assessments, tissue studies and long term multigenerational studies to identify any damage from eating GM foods that accumulates in children, grandchildren and great grandchildren.

Mostly the same?

The global industries that produce and lobby for a genetically modified future, unlike industries of comparable sizes including the mobile phone industry and the pharmaceutical industry however, are not required to produce any of these things.

Instead they rely on a method called ‘substantial equivalence’ i.e. they are allowed to claim – on the basis of no evidence whatsoever – that GM crops are mostly the same as others.

Substantial equivalence has been described in the hard-line scientific journal Nature as a “pseudo-scientific concept” which was “created primarily to provide an excuse for not requiring biochemical or toxicological tests”.

With this method just a few key chemicals, such as nutrients and known toxins are compared to those in the non-GM plant. If the levels are considered similar the whole plant is considered to be substantially equivalent to its non-GM counterpart.

Unfortunately, this process leaves literally thousands of plant chemicals, which have been potentially altered through genetic modification, unidentified and untested. What is more, current testing methods only look for nuclear DNA (that is the DNA found in the nuclei of cells) as opposed to the more abundant chloroplast DNA (the DNA found in organelles, those part of the plant cell which are responsible for photosynthesis).

A legacy of GM damage in animals

Nuclear DNA does not appear to survive food processing or digestion, but chloroplast DNA does and fractions of genetically modified chloroplast DNA from animal feed can be found in milk, eggs and meat.

Most of the studies upon which industry relies to ‘prove’ the safety of GM foods are not safety studies at all. Instead they are studies designed to evaluate the effect of GM crops on commercial feed performance indicators such as livestock growth rates or milk production. Deducing safety from such studies is rather like looking for elephants at the bottom of the ocean and, having found none, concluding that elephants don’t exist.

A useful, if alarming, briefing paper by the Soil Association, GM Crops – The Health Effects, pulls together the safety data to date on what happens when animals consume GM foods.

The only long term feeding trial (lasting 24 months) found that consumption of Roundup Ready soya affected key body organs, and changed the cell structure and cell functioning of the  liver, pancreas and testes in mice. Monsanto’s own testing has found that rats eating GM maize (MON863) developed smaller kidneys and showed startling changes in blood chemistry including an increased white blood cell count (indicating an immune response to the food).

In a 2005 Russian trial female rats were fed Roundup Ready soya before mating, during pregnancy and during lactation: 56% of the rat pups born to mothers on the GM diet died within 3 weeks of birth, compared to just 9% of those whose mothers ate a non GM diet. Amongst the surviving GM-fed pups there was stunted growth, and smaller organs.

Two US trials reviewed in the book Food Safety: Contaminants and Toxins (CABI Publishing 2003 – available online in Google books) have also found unexplained deaths amongst test animals, with 7 of 40 rats (17.5 %) in a feeding study of GM tomatoes dying within two weeks, and a 7% mortality rate for chickens fed GM glufosinate-tolerant Chardon LL maize (twice the rate of the non-GM fed chickens).

In 2005 an Australian study showed that the transfer of a ‘safe’ gene into a different plant species produced allergic reactions in mice that consumed genetically modified peas.

In 2009 a study in the International Journal of Biological Sciences showed that GM corn and other GM food could be contributing to the obesity epidemic. In addition to the same type of organ dam age seen in previous studies, mice fed GM corn showed an overall increase in body weight of nearly 4%.

GM DNA survives in the human gut

Two UK trials funded by the Food Standards Agency – one the only known trial involving humans eating GM soya, the other with sheep eating GM maize – found that some of the inserted genes remained in the gut after ingestion and were transferred to the gut bacteria. This effect is particularly worrying because of the health implications for humans if gut bacteria start showing certain GM traits such as resistance to antibiotics (which can evolve from the herbicide resistance trait), or producing a transgenic protein such as the Bt toxin (exposure to which is linked to allergic reactions)

Other studies have found the potential to cause haemorrhage in the gut. Two separate feeding trials have found that GM potatoes caused lesions (weak spots) in the gut wall of rats and mice, and two unpublished US feeding trials using GM tomatoes also found lesions in the gut wall of rats. These are reviewed in reviewed in the book, referenced above, Food Safety: Contaminants and Toxins.

The science of small exposures

When it comes to food safety, it is inevitably the smallest things that cause the most harm; things like bacteria, viruses, prions, acrylates, packaging contaminants, dyes and other additives.

The human system is exquisitely sensitive and responsive to things that shouldn’t be there, are there at the wrong time, or in the wrong amounts. All the more worrying, then, that GM toxins have been detected in the blood of the vast majority of mothers and babies tested.

Where the damage comes from

While the causes of all the effects documented so far in animals, and what this might mean for human health is not known – several factors could be influential.

For all its claims of scientific excellence, the genetic modification process is a crude one. There’s a lot of trial and error involved in inserting the genes from one animal or plant into just the right place into the genetic material of another and it is still not possible to insert a new gene with any real accuracy.

The artificial insertion of a gene can disrupt the function of other genes through the damage caused by the insertion process. In addition, the chemical functioning of the new gene may  interact with the activity of the plants’ existing genes and biochemical pathways, and this can disrupt its metabolism in unpredictable ways.

Beyond genetics

However, newer research is showing that genes account for only a part of the control of the biochemistry of organisms: and that there is a level of control above genes that regulates their activity.

The mechanism of this interaction is largely unknown and the relatively new study of it is known as ‘epigenetics’ (literally above genetics).

What epigenetic research has shown so far is that the mechanics of genetics is many times more complex than our crude science (and regulatory processes) can account for. Far from reassuring us that we know all we need to know to prove the safety of GM food, epigenetics has highlighted how pathetically skimpy our understanding is.

Once we take that step into the world of genetically modified food, there is no turning back. You can’t simply unplant GM crops. You can’t remove pollen contamination from non-GM crops or traces of GM from the food system.

Like drugs such as DES that have generational effects, the health damage caused by GM may also pass down the human and animal bloodline in unpredictable ways. Before we allow ourselves to become shackled to a future with so few options, we should be much more demanding of the science and the claims of ‘safety’ of this proposed new way of feeding the world.