GM-free Scotland

News | August '08 | An explosion looking for a place to happen


An image of a maize bombWe have had four major warnings of the potential for unexpected harmful qualities to emerge in GM foods.

  1. In 1989, a rogue batch of tryptophan food supplement pills were responsible for 31 deaths and 1,511 chronically disabled. These statistics apply only to the USA, as records were not compiled in other countries where the pills were sold. The offending supplement contained extracts from a bacterium, Bacillus amyloliquefaciens, transformed with a stack of four genes to make it overproduce the desired tryptophan. Investigation revealed trace amounts of a toxic by-product, which the GM-lobby was quick to blame on inadequate purification procedures: the company responsible denied this. The GM bacteria, which can never be recreated because genetic transformation is unpredictable, were destroyed, and no further investigation has ever been possible.
  2. In 1996, a Brazil nut gene was inserted into soya, tobacco, oilseed rape and beans. The aim was to generate novel proteins to make up for known deficiencies in nutrient composition of these crops, especially for animal feed. The transgenic protein was shown to be safe when fed to test animals, but experiments on human nut-allergy sufferers found it inexplicably provoked an immune response. This line of research was discontinued.
  3. In 1999, potatoes containing a pesticide-generating gene from a non-food plant (snowdrop) were found to be stimulating immune responses in the gastro-intestinal tract of experimental rats. The pesticide itself, in extracted form, had been proved safe. This experimental programme was halted before completion and the scientists fired; it has never been repeated.
  4. In 2005, peas transformed with a pesticide-generating gene derived from another food-plant (a bean) were tested on laboratory mice. The GM peas were found to have become allergenic, and worse, were found to provoke allergic reactions to common proteins. The commercial development of these peas was abandoned.

Look now at the assessment procedure used to 'check' the safety of GM foods.

It focuses on:

  1. The history of safe use of the transformed and source organisms (referred to in the US as GRAS, 'generally recognised as safe').

    2. Nothing in the four warnings described above failed the safe-history test, but they all have question marks over them depending on how you define 'safe'. Potatoes are known to produce toxins on occasion (they belong to the deadly nightshade family), soya is known to produce anti-nutrients and hormone disruptors and is a common allergen, beans are known to produce anti-nutrients, Brazil nuts are notorious for occasional lethal allergic reactions (that was the only reason the soya with Brazil nut gene could be tested), snowdrops aren't recognised as toxic plants but neither are they a food, and all bacteria have the potential to cause disease because they evolve quickly and can swap genes with each other, while even the most benign can become an opportunistic pathogen. How do you decide what factors can be ignored when assessing the historical 'safety' of any of these organisms, especially when you are about to change them at their most fundamental level. How relevant is the previous knowledge of any organism whose genome function has since been disrupted?

  2. The safety of the protein generated by the inserted gene.

    3. None of the four warnings failed this test.

    Despite its safety always being a prime consideration, the GM protein is rarely, if ever, actually tested. Instead, a similar, purified protein derived from another GM organism is used. This substitute will probably have been fed to rats, and if they don't keel over during the experiment, the untested actual GM protein is held to be 'safe'. Any remaining doubts will be dispelled by subjecting the purified protein substitute to a laboratory-simulated 'digestion': if the protein disappears, or looses its activity, the untested actual GM protein is held to be 'safe'.

    The science here is non-existent: the tests are carried out on a different protein ('similar' is not scientifically nor toxicologically valid); the 'digestion' is carried out under optimum conditions without the presence of interfering materials, which never happens in reality. Moreover, tests on animals may not have any relevance to humans, and are valueless unless followed by clinical studies.

  3. Acute toxicity of the food to rodents.

    4. There is no reason why all four warnings above might not have passed this 'test' with flying colours.

    The GM food may be force-fed to rats for a few days or weeks. If there are no gross symptoms of ill-health, the food is 'safe'. If the food is also intended for animals, feeding tests will be carried out to ascertain its nutritional, and therefore commercial, usefulness; tests on livestock (ruminants, birds etc.) are not relevant to humans and since intensively reared animals are never intended to live very long, chronic effects from the feed are not of interest.

  4. Chemical composition

    5. None of the four warnings described above would have had any problem with this 'safety' test, especially the lethal, highly purified tryptophan.

    This test measures breakdown products (assuming complete digestion), and known toxins. It provides an important check of the feed quality for intensively reared livestock whose diet is restricted, but is of questionable relevance to most humans who eat a large variety of different foods, and is incapable of revealing the presence of any novel toxin or allergen. The routine employed seems to be that when statistically significant differences in composition are identified in GM food compared with its non-GM counterpart, these are dismissed by forgetting the science and introducing a 'comparator' plant or even a whole set of 'comparator' plants instead of a control, or applying the imaginative but undefined concept of 'biological significance', or even 'substantial equivalence'.

  5. Stability

    6. Lack of stability of the novel DNA construct and, more especially, of the DNA of its host genome, may have been a factor in any of the four warnings.

    Tests of stability are restricted to the function of the transgene (i.e. does the GM plant retain herbicide-tolerance or its ability to kill insects). This characteristic may be irrelevant because the DNA can change without altering the activity of the protein it generates (see MON810: IS THIS REGULATION? - News, June 2008). There is also has a time-factor, which is never examined: this year's 'safe' food might be next year's killer.

Note. Have you noticed how often questions of 'relevance' pop up in all of this?

Here are some even bigger warnings to emerge from the ones we've already described:

Toxic by-products in trace quantities in food can survive processing and can cause chronic disease or death. These will only be noticed if they produce distinctive symptoms and if their source can be clearly identified (i.e. if they are bought and consumed knowingly, and fully traceable).

Allergens, and allergen-sensitisation, can be generated in a totally unpredictable manner.

Adverse reactions to novel foods leading to chronic disease are only likely to be apparent in short-term animal testing if microscopic examination of the cells of the intestinal lining and other major organs is included.

With the help of the biotech industry, whose expertise does not lie in the field of food safety testing, focus is carefully directed onto these limited, unscientific, or invalid tests and away from any relevant, targeted testing of possible harm to people.

The risk review carried out at the Stockline factory in Glasgow, where a gas explosion caused the tragic loss of nine lives, had many uncomfortable parallels to GM risk assessment: the person who carried out the routine checks wasn't fully qualified nor experienced; the (highly significant) age of the pipes was noted and then ignored; the underground pipes whose corrosion led to the fatal gas leak were simply not part of the inspection.

Downing Street insists the Prime Minister's view on GM is that “we must be guided by the scientific evidence”, while the Environment Minister reiterates that “ ... safety is the top priority and that GM crops are to be considered on a case-be-case basis, based entirely on the science”. So, ask them to GET the scientific evidence of safety, before we have a silent explosion of chronic ill-health.


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