Substantial equivalence

In the early-to mid 1990s, with the development and commercialisation of genetically modified food (GM foods) becoming an imminent possibility, national and international authorities began to consider a framework for the regulation of the new technologies. The "substantial equivalence" approach was eventually adopted. The exact definition of "substantial equivalence" in this context is hard to pin-down. Indeed the definition of the term proved so elusive that the approach was subjected to several conflicting interpretations.

Initially, it meant that if a GM food was thought to be "substantially equivalent" to its traditional counterpart then risk assessments were deemed unnecessary. The test compared, for example, protein, carbohydrate and fatty acid levels between the novel food and its traditional counterpart. Crucially however there were no clear and universal guidelines over exactly what to test and how similar the two should be. Therefore, the amount of comparative data that was required to establish "substantial equivalence" involved "a somewhat subjective judgement" (Royal Society 2002: 5-6).

Perhaps unsurprisingly, then, the approach proved immensely controversial. Consumer organisations, environmental groups and a few leading scientists criticised "substantial equivalence" for helping to play down the novelty of GM technology and thus facilitating its commercialisation. In response, over the years, the approach came to mean something very different and ultimately it was demoted as a regulatory tool - albeit implicitly.

The capability to classify a novel food as being "substantially equivalent" no longer justifies a lack of safety assessments. The regulatory process now places much more emphasis on identifying the unintended consequences of genetic modification. Moves are being made to develop better methods for testing composition, metabolic activity, toxicity, allergenicity, etc. In contrast to its initial implementation, now the official consensus is that "substantial equivalence" should only be used to guide safety assessments, as a starting point in the regulatory process and not an end point.

Bibliography

Royal Society (2002) Genetically Modified Plants for Food Use and Human Health – an update, [1]