Below is an excerpt from our published paper: Ho, M.W. and Steinbrecher, R. (1998). Fatal flaws in food safety assessment: critique of the joint FAO/WHO biotechnology and food safety report, Environmental & Nutritional Interactions 2, 51-84. We are reproducing the Section on the principle of substantial equivalence to show how rediculous it is.
The most serious shortcomings of the report are in the principle of "substantial equivalence" on which all safety assessment is based.
"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)" (Joint FAO/WHO Biotechnology and Food Safety Report, 1996, p. 4)
This principle is unscientific and arbitrary, encapsulating a dangerously permissive attitude toward producers, and at the same time it offers less than minimalist protection for consumers and biodiversity, because it is designed to be as flexible, malleable, and open to interpretation as possible.
"Establishment of substantial equivalence is not a safety assessment in itself, but a dynamic, analytical exercise in the assessment of the safety of a new food relative to an existing food. The comparison may be a simple task or be very lengthy depending upon the amount available knowledge and the nature of the food or food component under consideration. The reference characteristics for substantial equivalence comparisons need to be flexible and will change over time in accordance with the changing needs of processors and consumers and with experience." (Joint FAO/VMO Biotechnology and Food Safety Report, 1996, pp. 4 and 5)
In other words, one can choose to compare whatever is the most convenient at a particular time, and for a particular purpose. And if on one set of criteria the product is not substantially equivalent, a different set of criteria could be used, always to the advantage of the producers.
In practice, this principle allows comparison of the transgenic line to any variety within the species, and even to an abstract entity made up of the composite of selected characteristics from all varieties. That is exemplified in the safety evaluation reported by the company Calgene on several of their products (Redenbaugh et al., 1995). By a judicious use of additional varieties, any changes from the control recipient variety could be bracketed. In theory, a genetically engineered line could have the worst features of every variety and still be substantially equivalent. Such comparisons rather than comparing the transgenic line to the parental nontransgenic line would rarely, if at all, pick up significant changes resulting from the genetic modification per se, which should alert conscientious researchers to a more careful characterisation of the genetically modified organism-
Bernard Shaw was reputed to have been propositioned by a beautiful though not too bright lady who wanted to have his child so it would have his brains and her looks, 'but Shaw was said to have discouraged her by pointing out that the child could end up having her brains and his looks instead. So, it is the particular combination of characteristics that makes all the difference. But under the present safety assessment regime, both combinations would be deemed "substantially equivalent." The danger is that particular combinations of nutrients or metabolises might fall within the "equivalent" range determined in this fashion, and yet be antinutritional, toxic or cumulative lethal.
And if that were not enough, producers are assured that, even when products are not substantially equivalent, they can be shown to be substantially equivalent except for defined differences, and "further safety assessment should focus only on those defined differences" (Joint FAO/W'HO Biotechnology and Food Safety Report, 15)96, p. 8). Lest one is in any doubt, it is stated an page 11 of the report that "UP to the present time, and probably for the near future, there have been few, if any, examples of foods or food components produced using genetic modification which could be considered to be not substantially equivalent to existing foods or food components." Calgene's genetically engineered Laurate canola oil should, by no stretch of the imagination, be considered substantially equivalent to ordinary canola oil. But, "other fatty acids components are Generally Recognised as Safe (GRAS) when evaluated individually because they are present at similar levels in other commonly consumed oils." Similarly, "substitution of Laurate canola for coconut and palm kernal oils does not raise any safety concerns for intended uses, in part because the major components, the fatty acids laurate and myristate, are identical" (Rodenbaugh et al., 1996)
In other words, it is already a foregone conclusion that most, if not all, the products now and for the foreseeable future will be assessed as "substantially equivalent," and if not, then considered GRAS by a judicious choice of a comparator.
It is significant that the Dutch courts have recently ruled Monsanto's genetically engineered soy beans not equivalent in quality to natural soy beans, as was claimed in the advertisement of Albert Heijn, the biggest supermarket chain in the Netherlands. Albert Heijn is itself part of the Dutch multinational Ahold, which owns super- market chains in many countries around the world. The complaint was filed by the Dutch Natural Law Party (Storms, 1997).
Given that "substantial equivalence" can be interpreted in the widest possible sense--and if not, then by a judicious choice of comparator the product can be considered as GRAS-it is difficult to imagine which remaining products cannot pass muster.
The report recognised that "products could be developed which could be considered to have no conventional counterpart and for which substantial equivalence could not be applied" (Joint FAO/WHO Biotechnology and Food Safety Report, 1996, p. 11). For example, one phrase used is "products derived from organisms in which there has been transfer of genomic regions which have perhaps been only partly characterised" (p. 11) This gives the impression that such are hypothetical cases that might arise in future,
But that is not so. The report has failed to point out that at least one such transgenic organism already exists: Tracy, a sheep engineered with a large segment of a human genome-most of which contains unknown sequence with unknown functions--to produce huge quantities of alpha-antitrypsin in her milk (Colman, l996). Tracy and her clones may he walking incubators for cross-species viruses to arise by recombination between human and sheep viral sequences. All genomes contain endogenous proviral sequences, and recombination between endogenous and erogenous viral sequences are already implicated in several kinds of animal cancers (.5ce Ho, 1997a). One might think that the report would treat such cases with extra caution. Not so.
We are assured that even if a food or food component is considered to be not substantially equivalent, producers need not despair, for "it does not necessarily mean it is unsafe and not all such products will necessarily require extensive testing" (Joint FAO/WHO Biotechnology and Food Safety Report, 1996, p. 12). The-report seems to prepare the grounds for slipping those products through a regulatory framework that is already worse than toothless.
Further on, in Section 6.6 on "Food organisms expressing pharmaceuticals or industrial chemicals" (Joint FAO/WHO Biotechnology and Food Safety Report, 1996, p. 19), there is the telling statement, "The Consultation recognised that, generally, the genetically modified organism would not he used as food without prior removal of the pharmaceutical or industrial chemical" (p. 19). That is a prelude to serving up the rest of Tracy and the "elite herd' cloned from her, or, more likely, superannuated "pharm" animals and any failed transgenic experiment, whatever, as meat for our dinner tables. Transgenic technology is very inefficient and generates a lot of transgenic wastes--the large numbers of failed experiments. Such "foods" from transgenic wastes may be sources of exotic, cross-species foodborne viruses, as mentioned earlier. Furthermore, they will be exempt from safety assessment if the report is to be taken seriously. A similar category of transgenic waste could be the leftover carcasses of pigs engineered for xenotransplantation. All the signs are that the producers are handed carte blanche to do as they please for maximum profitability, with the regulatory body acting to allay legitimate public fears and opposition.
The procedure for establishing substantial equivalence, described in less than three pages in the 27-page report (pp. 6, 7, and 8), comes under two headings: 'background information an the characterisation of the modified organism, and actual determination of substantial equivalence, or characterisation of the food product itself.
One glaring omission in the background information is the propensity of the transgenic organism for gene-rating pathogenic viruses by recombination (and whether experiments have been carried out to investigate this propensity). This information is highly relevant for assessing impacts an biodiversity as well as food safety, in view of our current knowledge that superinfecting viruses may he generated from many transgenic plants at much higher frequencies than previously thought and that insecticidal recombinant viruses may attack human liver cells. There is also disturbing new evidence that viral DNA can survive digestion in the gastrointestinal tract of mice, with large fragments getting into the blood stream and into many kinds of cells (Schubbert et al., 1994, 1997).
Likewise, information on the stability of transgenes, and potential for mobility of introduced genes, which are mentioned on page 6 of the report, ought to 'be based on data collected over a number of generations, documenting the stability of the insert as well as expression of the transgenes and the transgenic line in successive generations, so that both consumers and farmers can have confidence in quality control. In a paper presented at a World Health Organisation (WHO) workshop, Conner stated, "The main difficulty associated with the biosafety assessment of transgenic crops is the unpredictable nature of transformation. This unpredictability raises the concern that transgenic plants will behave in an inconsistent manner when grown commercially" (Conner, 1995) In general, the inheritance of genetically engineered traits is non-Mendelian in subsequent generations (Schuh et al., 1993) necessitating clonal propagation.
Earlier this year, 60,000 bags of genetically engineered canola seeds, enough for planting 600,000 acres, had to be recalled after they were sold in western Canada, because unexpectedly a gene, not yet approved for market, turned up in the seeds. The seeds were bred and sold by Limagrain, under licence from Monsanto (reported in Mani- toba co-operator, 24/4/97, and in The Ram's Horn, No. 147, April 1997). If the transgenic plants had been monitored for genetic stability of both the transgenes and the transgenic line in successive generations, as they should have been, and careful records kept, those seeds would never have reached the market. This incident also indicates the necessity for product segregation, clear labelling, and postmarket monitoring as part of the condition for market approval.
Under background information, it is also crucial to include the upstream and downstream effects of transgenic promoter and enhancer sequences, as well as any possible regulatory elements contained in the coding sequences. Furthermore, the need identification and recently the presence of genetic elements in the host that might compromise the stability of the transgenes. A further serious omission in the background information is the lack of an explicit requirement to disclose the presence of marker genes, especially antibiotic marker genes, which are considered in a later section.
We are told in the report that "characterisation of the food product" entails "molecular characterisation," "phenotypic characterisation," and "compositional analysis." While the latter two categories are elaborated subsequently, "molecular characterisation" has mysteriously disappeared. Nowhere is it specified which methods of molecular characterisation are required, nor what molecular information should be established. Though this would be crucial for identifying unintended effects. A previous document that reports on a WHO Workshop on the principle of substantial equivalence, Applications of the Principle of Substantial Equivalence to the Safety Evaluation of Foods or Food Components From Plants Derived by Modern Biotechnology (WHO/FNU/FOS/95.1, p. 7), leaves molecular characterisation very vague. It refers to "the inserted DNA," and to "the level and mechanism of expression of the protein," which is considered to 'be "more important than knowing the gene copy number." It appears the inserted DNA sequence need not be well characterised at all. The report then mentions "the level and function of the introduced gene product in the plant may be useful in judging substantial equivalence," again implying that the function of the gene product need not be known as a condition for safety approval. If the gene(s) and gene product(s) transferred are well understood, however, the safety evaluation can then "focus on the safety of the expression product and/or changes "brought about by the expression product." This is an open endorsement of a totally inadequate, reductionist safety assessment that ignores effects on the system as a whole, especially in the longer term
In effect, a thorough molecular characterisation of the product is not required. Not even the level of expression of the introduced transgene(s) or marker gene(s) needs to be ascertained, much less the effects of promoters and enhancers on neighbouring genes, as judged by the samples of papers presented in the WHO workshop on substantial equivalence (see Health Aspects of Marker Genes in Genetically Modified Plants, Report of a WHO Workshop, WHO/FNU/FOS.93.6, 1993). If one happens to know what has been transferred, then safety assessment can focus only on the gene product and its effects- So the two main categories of characterisation of the food product are simply the phenotypic characteristics-agronomic, morphological, and physiological-and the compositional comparison-key nutrients and toxicants that are known to be inherently present in the species.
Although the report recognises the possibility of "indirect consequences" (p. 4) and that "assessment of the safety of genetically modified organisms must address both intentional and unintentional effects that may result as a consequence of the genetic modification of the food source" (p. 5), these are limited to phenotypic changes that are readily apparent, and alterations in the concentrations of major nutrients or increases in the level of natural (known) toxicants. There is thus no specific requirement to test for unintended effects per se.
Similarly, while it is stated that "attention must be paid to the impact of growth conditions on level of nutrients and toxicants" and "attention must be paid to the impact of different sails and climatic conditions" (p. 5), these are not elaborated further, and certainly are not required for safety assessment recommended in the report.
The range of tests that are actually carried out, as exemplified by WHO's Workshop Report on applying the principle of substantial equivalence, are not sufficiently discerning to pick out unintended effects Unless there are gross morphological or phenotypic changes, there is no need to lock for them. And even when there are gross abnormalities, the product can still be assessed to be "substantially equivalent." One paper presented in the WHO workshop reported, "Field trials on the transgenic lines used in these studies showed marked deformities in shoot morphology and poor tuber yield involving a low number of small, malformed tubers during field trials.... These changes were attributed to somaclonal variation during the tissue culture phase of transformations. Despite these marked morphological abnormalities, virtually no changes in tuber quality attributes were detected" (Conner, 1995). So much for the discerning power of the tests carried out.
There were no metabolic profiles done by routine analytical techniques such as high-pressure liquid chromatography (HPLC), or two-dimensional gel electrophoresis to scan for unintended expression of genes. The compositional analyses reported are limited to uninformative amino acid profiles, or to known components present at levels greater than 0.1%, or 0.01% at best. And, as mentioned earlier, the arbitrariness of the comparison will already hide any changes due to the transferred gene(s) per se, which should alert researchers to unintended effects. Instead, the tests are aimed specifically at intended effects only, and, if anything, at concealing secondary, unintended effects as much as possible.
The hazard of unintended effects is already well attested to by the U.S. epidemic of eosinophilia-myalgia syndrome in the U.S. in 1990, resulting in more than 1500 affected and 37 deaths, which is linked to the consumption of L-tryptophan produced by a genetically modified strain of Bacillus amyloliquefaciens (Mayeno & Glich, 1994). Several trace contaminants identified by HPLC have been implicated in pathogenesis of this syndrome.
A metabolite, mothylglyoxal, was found to accumulate at toxic, mutagenic levels in yeasts engineered with multiple copies of one of several yeast glycolytic enzymes to increase the rate of fermentation (Inose & Murata, 1995). Recently, tobacco plants genetically engineered to produce the gamma-linoleic acid also unexpectedly produced actodecatetraenoic acid, a substance previously unknown in natural tobacco plants (Reddy & Thomas, 1996). In the absence of a metabolic profile on the product, unintended toxic metabolites might have easily escaped notice in safety assessment.
It is equally important to cheek for unintended gene products being produced, which will not be revealed by routine amino acid analyses of total lysates, as is done by Calgene for canola meal (Redenbaugh et al., 1995). A minimum requirement should be a two- dimensional gel electrephoretogram of the total proteins. Even then, minor modifications in a proportion of the proteins may not be detect- able, which may change the properties of the proteins involved. For example, a proportion of the recombinant porcine and bovine somatotropins synthesised in Escherichia coli were found to contain the abnormal amino acid e-N-acetyllysine in place of the normal lysine only when reversed-phase HPLC analyses were carried out (Voland et al., 1994).
Key questions on the allergenic potential of transgenic foods are raised by the recent identification of a brazil-nut allergen in soybean genetically engineered with a brazil-nut gene (Nordlee et al., 1996). It is possible to test for known allergens, as in the case of the brazil-nut soybean, but not for allergenicity to proteins completely new to the foods involved, as acknowledged in the report (Joint FAO/WHO Biotechnology and Food Safety Report, 1996, p. 14). It is significant that allergenicity in plants is thought to be linked to proteins involved in defence against pests and diseases (Franck & Keller, 1995). Therefore, transgenic plants engineered for resistance to diseases and pests may have a higher allergenic potential than the unmodified plants. Furthermore, it has been shown that common food allergens are invariably proteins that have been glycosylated. The whole area of glycosylation and, in fact any posttranslational modification of GE proteins, needs urgent attention with regard to allergenicity. One major novel protein is the insecticide produced by the gene from Bacillus thuringiensis (Bt), now incorporated into a range of transgenic crop plants that had never contained them before. Nevertheless, the producers were able to claim substantial equivalence by pointing to its "comparability" (not identity!) "to one of the proteins contained in the commercial microbial formulations that have been used commercially since 1988" (Fuchs et al., 1995). In fact, the genetically engineered Bt loxin is a truncated, immediately active form of the protein produced by the bacteria itself and is thus entirely new to our diet. One important characteristic of an allergen is that it resists digestion in the stomach (gastric digestion). According to a recent publication (Astwood et al., 1996), known allergens wore stable for 60min, whereas nonallergens were fully digested within 15 s. While one study claimed the Bt protein was readily digestible (Fuchs et al., 1995), another report showed that it failed to he completely digested under gastric conditions after 2 h (Noteborn & Kuiper, 1995). In both cases, we are assured that the protein is safe. In view of the recent discoveries that predators eating pests that have ingested the Bt toxin in transgenic crop plants are also harmed (Bigler & Keller, 1997; Hawkes, 1997), it is irresponsible to assume that the toxin is safe for human, especially [in the] long term.
We accept that no safety assessment system is foolproof. A case in point is the rigorous testing that goes on with pharmacological products. It is estimated that despite such rigorous testing, 3% of the products approved for market turned out to have such harmful effects that they have to be withdrawn, while an additional 10% have sufficiently harmful side effects that limited use has to be recommended (Suurkula, 1997). This underlines the importance of segregation, clear labelling, and postmarket monitoring of the health and other impacts of genetic engineered foods. Labeling is a matter of traceability, especially for the case of potential allergenicity, and should be a scientific requirement, not only a consumer option.
Article first published 1999
Got something to say about this page? Comment