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Fundamental flaws – Poorly defined
1.
The most obvious problem with ‘Substantial Equivalence’ assessments is that they are simple compositional analyses which are unlikely to detect the unexpected or unintended impacts of genetic modification. Assessments can only detect problems they are designed to look for. ‘Substantial Equivalence’ assessments are limited in scope because they only look for known substances, not unknown substances.
2.
The premise which forms the bedrock of ‘Substantial Equivalence’ is problematic because it assumes science knows about the safety of conventional foods against which GM foods are required to be evaluated. Historically food safety concerns have focused on issues of contamination from disease causing bacteria or industrial chemicals rather than attempting to analyse how food compounds interact with human health. This makes meaningful comparisons between conventional food and GM food almost impossible. Similarly, the lack of extensive background information on conventional food crops as they effect the environment makes it extremely difficult to conduct environmental impact assessments on GM crops.
3.
The concept of ‘Substantial Equivalence’ is ill defined and open to interpretation. What actually constitutes a ‘substantial degree of equivalence’ between a GM food and a non-GM food has never been clearly defined and therefore may be applied in starkly different ways. This can be seen in how differently substantial equivalence judgements are made in the USA and Europe. The EU stipulates that a GM food can only be considered to be substantially equivalent to a non-GM food if it does not contain any GM protein or DNA, and shows no other differences in composition. The US position (GRAS) is almost exactly the opposite – it presumes GM protein and non-GM protein are substantially equivalent unless shown otherwise.
4.
The concept of ‘Substantial Equivalence’ will become less effective as an assessment tool as GM foods become more complex. The greater the difference between a GM crop and its non-GM counterpart, the more difficult it is to apply the concept of ‘Substantial Equivalence’. It has already been pointed out that comparing GM foods with non-GM foods is difficult because we lack scientific knowledge about conventional foods. As GM foods become more complicated (more genes added, or more radical genetic changes made) comparisons between them and non-GM foods will become almost impossible to make. The EU has sought to solve this problem by suggesting that the more different GM foods become to conventional ones, their ‘Substantial Equivalence’ should be assessed against existing GM foods. This proposal does not solve the problems already associated with the concept of ‘Substantial Equivalence’ - moreover it is likely to increase the uncertainty of the concept given that mistakes made with one generation of GM foods could be rolled-over and compounded into the next.
Scientists recognise the limitations
“The use of substantial equivalence as a decision threshold by regulatory agencies is, in the Panel´s view, scientifically unjustifiable when used to exempt new products from full scientific scrutiny.” The report went on to say that GM food or feed “should be based on rigorous scientific assessment of their potential for causing harm to the environment or to human health. Such testing should replace the regulatory reliance on substantial equivalence as a decision threshold.”
(See: Elements of Prediction: Recommendations for the Regulation of Food Biotechnology in Canada, a report published by the Royal Society of Canada, January 2001.)
“We are looking at such a very large, potential range of transgenic crops and foodstuffs in the future that I think the whole concept, the framework, of substantial equivalence will assume increasing importance. And used in the way that it is currently used, I do not think it will necessarily be adequate for that purpose.”
(Dr. Andrew Chesson, senior scientist at the Rowett Research Institute and a member of one of the EC´s scientific advisory committees, giving evidence to the UK government´s Select Committee on Science and Technology in 1999.)
“Substantial equivalence is a pseudo-scientific concept because it is a commercial and political judgement masquerading as if it were scientific. It is, moreover, inherently anti-scientific because it was created primarily to provide an excuse for not requiring biochemical or toxicological tests. It therefore serves to discourage and inhibit potentially informative scientific research. The case of GTSBs (GM glyphosate-tolerant soya beans) shows, moreover, that the concept of substantial equivalence is being misapplied, even on its own terms, within the regulatory process. If policymakers are to provide consumers with adequate protection, and genuinely to reassure them, then the concept of substantial equivalence will need to be abandoned, rather than merely supplemented. It should be replaced with a practical approach that would actively investigate the safety and toxicity of GM foods rather than merely taking them for granted, and which could give due consideration to public-health principles as well as to industrial interests.”
(A reference from an article by E. Millstone, E. Brunner and S. Mayer, ‘Beyond 'substantial equivalence'’, in Nature 401 (1999), pp. 525–526.)
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