Before you eat it ask: just how ‘safe’ is safe?
The Government and Big Biotech say GM food is safe to eat, but with no trials conducted on humans, what they call ‘safe’ and what we call ‘safe’ may be two very different things. Pat thomas reports
When it comes to food safety, it is inevitably the smallest things that bring us to our knees; things that exist in our foods in relatively minute amounts – bacteria, viruses, prions, acrylates, packaging contaminants, dyes and other additives – but which nevertheless have the potential to cause large-scale harm. It’s worth bearing this in mind when considering the safety of genetically modified 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 fed on GM-containing feed. In the us, GM is more widely consumed as food additives and in animal feed. Such is the way of the global food system, however, that it is impossible to guarantee that conventional crops have not been contaminated to some degree with their genetically modified equivalents, either by cross-pollination or simply by getting mixed together in a storage facility.
Although hardly grounded in sound science, the fact that we may all already be eating GM food to some degree – and potentially for some years – is the core of the ‘safety’ argument put forward by Big Biotech and the Government.
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 that accumulates in children, grandchildren and great-grandchildren.
Unlike other large industries, such as those making mobile phones and pharmaceuticals, however, the GM industry is not required to invest in these studies.
Instead, it is allowed to rely on a method called ‘substantial equivalence’ – described in the journal Nature in 1999 as a ‘pseudo-scientific concept’ that was ‘created primarily to provide an excuse for not requiring biochemical or toxicological tests’. Using 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 (i.e. The DNA found in the nuclei of cells), as opposed to the more abundant chloroplast DNA (the DNA found in organelles, those parts of the plant cell responsible for photosynthesis). 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 recent briefing paper by the soil association pulls together the safety data to date on what happens when animals consume GM foods. It makes for alarming reading.
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 lactation; 56 per cent of the pups born to mothers on the GM diet died within three weeks of birth, compared with nine per cent of those whose mothers ate a non-GM diet. The surviving GM-fed pups showed stunted growth and smaller organs.
Two US trials have also found unexplained deaths among test animals: seven out of 40 rats (17.5 per cent) in a feeding study of GM tomatoes died within two weeks, and there was a 7 per cent 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.
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 genetic material remained in the gut after ingestion, and was transferred to gut bacteria. This has particularly worrying health implications for humans, if gut bacteria start showing certain GM traits, such as resistance to antibiotics, or producing a transgenic protein such as the Bt toxin (linked to allergic reactions). Other animal studies involving GM potatoes and tomatoes have found the potential to cause haemorrhage in the gut.
The causes of these effects, and how they might play out in the human body, are unknown, but could be related to several factors. Artificial insertion of a gene, for instance, can disrupt the function of other genes through the damage caused by the insertion process. Similarly, the chemical functioning of the new gene interacts with the activity of existing genes and biochemical pathways, and this can disrupt plant metabolism in unpredictable ways.
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. This relatively new area of study is known as ‘epigenetics’ (literally ‘above genetics’), and what it has shown so far is that the mechanics of genetics is many times more complex than our relatively crude science (and regulatory processes) can cope with. Far from reassuring us that we know all we need to know to step forward with confidence into a genetically modified future, it highlights how dangerously lacking our understanding is.
Once we take that step into the world of genetically modified food, there is no turning back. Before we allow ourselves to become shackled to such a future, we should be much more demanding of the science and the claims of ‘safety’ of this proposed new way of feeding the world.
Pat Thomas is Editor of the Ecologist
- This article was part of a special series of articles on GM in the November 2008 edition of the Ecologist. This article is not available online.
