Substantial Equivalence - Substantial Equivalence

Substantial Equivalence

"Substantial equivalence" is a starting point for the safety assessment for GM foods that is widely used by national and international agencies - including the Canadian Food Inspection Agency, Japan's Ministry of Health and Welfare and the U.S. Food and Drug Administration, the United Nation’s Food and Agriculture Organization, the World Health Organization and the OECD.

A quote from FAO, one of the agencies that developed the concept, is useful for defining it: "Substantial equivalence embodies the concept that if a new food or food component is found to be substantially equivalent to an existing food or food component, it can be treated in the same manner with respect to safety (i.e., the food or food component can be concluded to be as safe as the conventional food or food component)". The concept of substantial equivalence also recognises the fact that existing foods often contain toxic components (usually called antinutrients) and are still able to be consumed safely - in practice there is some tolerable chemical risk taken with all foods, so a comparative method for assessing safety needs to be adopted. For instance, potatoes and tomatoes can contain toxic levels of respectively, solanine and alpha-tomatine alkaloids.

To decide if a modified product is substantially equivalent, the product is tested by the manufacturer for unexpected changes in a limited set of components such as toxins, nutrients, or allergens that are present in the unmodified food. The manufacturer's data is then assessed by a regulatory agency, such as the U.S. Food and Drug Administration. That data, along with data on the genetic modification itself and resulting proteins (or lack of protein), is submitted to regulators. If regulators determine that the submitted data show no significant difference between the modified and unmodified products, then the regulators will generally not require further food safety testing. However, if the product has no natural equivalent, or shows significant differences from the unmodified food, or for other reasons that regulators may have (for instance, if a gene produces a protein that had not been a food component before), the regulators may require that further safety testing be carried out.

A 2003 review in Trends in Biotechnology identified seven main parts of a standard safety test:

1. Study of the introduced DNA and the new proteins or metabolites that it produces;
2. Analysis of the chemical composition of the relevant plant parts, measuring nutrients, anti-nutrients as well as any natural toxins or known allergens;
3. Assess the risk of gene transfer from the food to microorganisms in the human gut;
4. Study the possibility that any new components in the food might be allergens;
5. Estimate how much of a normal diet the food will make up;
6. Estimate any toxicological or nutritional problems revealed by this data in light of data on equivalent foods;
7. Additional animal toxicity tests if there is the possibility that the food might pose a risk.

There has been discussion about applying new biochemical concepts and methods in evaluating substantial equivalence, such as metabolic profiling and protein profiling. These concepts refer, respectively, to the complete measured biochemical spectrum (total fingerprint) of compounds (metabolites) or of proteins present in a food or crop. The goal would be to compare overall the biochemical profile of a new food to an existing food to see if the new food's profile falls within the range of natural variation already exhibited by the profile of existing foods or crops. However, these techniques are not considered sufficiently evaluated, and standards have not yet been developed, to apply them.

There are controversies over the definition and application of substantial equivalence. See section in genetically modified food controversies.