Food Safety Assessment of GM Crops and Pesticides– Similarities & Differences Robert Hollingworth Institute for Integrative Toxicology

June 27 June 12

HT – Herbicide tolerance Bt – Bacillus thuringiensis

Meet Cobzilla and Frankenfood

Method of Producing Transgenic Plants Insertion of a “foreign gene into a plant (40,000 genes) Selectable marker e.g. Further plant breeding and selection Final variety Modified Ti Plasmid stop Vector transferred to Agrobacterium

Common GM Traits Herbicide Tolerance Insect Resistance Virus Resistance Stacks Drought Tolerance Nutritional/processing improvement High oleic oils Low acrylamide production Anti-browning B-Carotene levels (Vitamin A) Iron fortification

Human Nutrition Challenges in Uganda Micronutrient undernutrition Micronutrient deficiencies are rated by the World Health Organisation as one of the most serious world public health problems The major micronutrient deficiencies in Uganda are: Vitamin A deficiency (VAD) Iron deficiency anaemia (IDA) Demographic and Health Survey 2006: 15-32% of children < 5 years had VAD 13-31% of women had VAD 50-80% of children < 5 years had IDA 32-64% of women had IDA

FDA’s 1992 Policy for Foods Derived from New Plant Varieties Safety evaluation is based on the objective characteristics or components of the food, rather than its method of development. Applies to all methods of breeding, including recombinant DNA New foods are evaluated relative to their traditional counterparts Standard is “as safe as” conventional food

Regulation of biotech.-derived organisms and foods in the US Philosophy: Biotech. introduces no novel risks, so new regulatory laws are not needed. These organisms, and foods made using them, are therefore handled under existing laws. Results: Complexity – Depends on the type of organism and modification and its intended use: Three regulatory agencies are involved (EPA, FDA, USDA) Regulation is possible under as many as 10 laws. For detailed information see: pewagbiotech.org/resources/issuebriefs/1-regguide.pdf

US Biotech Regulation 1986 Coordinated Framework: - Regulate based on product use - Use existing laws and regulations - Agency coordination http://usbiotechreg.nbii.gov Environmental Protection Agency US Department of Agriculture (APHIS) Food & Drug Administration FIFRA; TSCA PPA FFDCA Plant-Incorporated Protectants (PIPS) e.g. Bt protein; treated as pesticides Biotech. pesticides (microbial) Herbicide and insecticide resistance management Import, transport, planting of transgenic organisms. Food & feed safety; Labeling Key factor is the intended use of the product: Food items or drugs are regulated under FFDCA Industrial agents under TSCA , etc.

FDA approach to regulation of biotech foods and feeds Food components from GM organisms are presumed to be GRAS (Generally Recognized As Safe) unless they “differ significantly in structure, fuction or composition from substances currently existing in foods”. Manufacturers may, but are not required to, consult with FDA pre-market. However, such pre-market consultation is conducted routinely.

FDA’s Consultation Process Conducted by CFSAN (plants) & CVM (animals) Biotechnology Evaluation Team (BET) is established Initial Consultation: Food developer contacts FDA before market entry. Discussion of potential issues and data needs. Final Consultation: Biotechnology Notification submitted by the manufacturer requesting GRAS status including required data. Letter posted on FDA’s website. States that FDA has “no questions at this time” regarding the claims of safety in the submission. A memo describing the data and FDA’s analysis are also posted. As with the other voluntary premanufacturing consultation processes, the FDA makes no direct statement regarding the safety of the food.

Core Concept of Molecular Biology GENE (DNA) mRNA Transcription PROTEIN Translation Direct Effects (Toxicity, Allergy) ? Metabolites Enzymes, Cell structure ?

Assessing the safety of new expressed proteins: Toxicity History of safe use. Protein sequence homology to known vertebrate-toxic proteins. Toxicity when fed to vertebrates at high doses. If pesticidal, the product is regulated by EPA as a pesticide.

Mechanism of insect toxicity of Bacillus thuringiensis endotoxin

Assessing the safety of new expressed proteins: Allergenicity Case 1: Gene is from a known source of human allergens Can test the transgenic protein for any reaction with serum antibodies or skin reactions in sensitive people. Typically using genes from sources of known human allergens is avoided.

Assessing the safety of new expressed proteins: Allergenicity Case 2: Novel proteins – no history of allergenicity No single predictive test exists for allergenicity/no acceptable animal models. Current weight-of-evidence approach with mulltiple characteristics: Amount of protein Stability Heat/cooking Digestion Molecular characteristics of protein Sequence homology to know allergens Possible glycosylation Labeling of foods (typical approach with known allergens) Regulatory caution – StarLink corn example

Regulatory caution – the StarLink corn example StarLink corn was engineered to contain a Bt toxin (cry9c) that resisted digestion in the insect gut for greater potency. Unfortunately it also resisted digestion in the human gut and thus failed the “digestibility” test in the weight of evidence. Consequently it was not approved for human consumption in the USA, even though were no direct indications that it could cause allergies -- regulatory caution. However, it was approved for feeding to animals – a serious error. Soon afterwards it started to be found in many corn products in human foods in the US e.g. taco shells. Subsequent studies did not confirm any cases of allergy due to consumption of these products, but the foods were recalled. The total damages cost over $200 million. Now GM crops are not approved for non-food uses if they are not also safe for human consumption.

Expected Changed metabolic pathways Unintended effects Expected Changed metabolic pathways Unexpected Increase of endogenous toxins Increase of endogenous allergens Decreased nutritional quality Other????

Standard Methods to Assess the Toxicity of Single Chemicals (e.g. pesticides): Animal Tests Animals are given very high doses of the single well-defined chemical in question compared to the expected human exposure level in order to identify any possible toxic effects. Unrealistically high doses are used because: a. It is desirable not to miss any possible toxic effects b. A small number of animals with low genetic variability are used in the tests c. Humans could be more sensitive than animals After a given exposure time (days to years) the animals are examined for a wide range of possible toxic effects.

Differences – single chemical vs whole food The standard methods used for assessing the toxicity of single chemicals in animals using high doses (e.g. ADI approach) have limited utility for assessing toxic effects from whole foods because: Foods are complex and variable mixtures of many chemicals – control diets are not identical to GM ones Whole foods can’t be fed at high doses: It would lead to nutritional imbalances They often contain natural toxicants They often are unpalatable to test animals The results of such studies therefore have limited predictability and can be difficult to interpret in terms of the risk of any individual food component. So: If it is difficult to assess absolute safety, another approach is needed –relative safety assessment using Substantial Equivalence

Substantial Equivalence Principle: If a transgenic food organism can be shown to be substantially equivalent in composition to that of a conventional organism of the same kind, the modified organism and its products should be judged to be as safe for consumption as the conventional ones. (OECD 1993) The assessment of substantial equivalence is not safety testing, but it is a critical process to determine what, if any, safety testing may be necessary. It is the recommended approach of WHO/Codex Alimentarius and is used by the US, EU and other regulatory bodies.

Substantial equivalence: Characterization of the transformation Description of the host plant/organism including known toxicants, allergens, nutrients and antinutrients, and its use as food. Similar description of the donor organism(s). Description of the transgenic plant/organism. Description of the mode of genetic modification(s). Characterization of the genetic modifications. e.g. number of copies and location of the transgene, stability of integration, expression. Assess possible effects of the transgene and plasmid components on the metabolism/metabolites of the organism.

Substantial Equivalence: Typical Data Examining Substantial Equivalence – typical approach: 1. Grow the transgenic plant, non-transgenic (near isogenic), and conventional ones under identical conditions in several locations. 2. Compare their chemical composition including: Fats, amino acids, fiber, minerals, vitamins Antinutrients (e.g. protease inhibitors, lectins) Known and potential toxic metabolites including any allergens 3. Conduct comparative nutritional studies in one or more animal species. 4. May add short term (3 month) dietary exposure toxicology studies in rodents if needed to resolve toxicological questions, but this is not routine (but recently required by the EU).

Polar Metabolites – Golden Rice Non-Transgenic Transgenic

Possible Outcomes from an Analysis of Substantial Equivalence No significant differences are discovered. The engineered and conventional crops are substantially equivalent. No further study is needed to confirm safety. A few defined differences are found. These would need further consideration to determine the level of risk and any further safety testing before the crop is cleared for use. Many differences are found and/or there obvious serious health implications in the differences. This situation would demand extensive (and probably very expensive) further study. The project would probably be abandoned.

Results from Substantial Equivalence Studies “A recent review of 20 years of literature has shown that for the 148 GM crops approved in the US and the 189 submissions in Japan, in every case substantial equivalence between GM crops and their conventional counterparts was judged to have been established. These studies covered the full range of trait modifications and several types of crops. A large number of academic studies also support this equivalency.” “In addition there is ample evidence that genetic modification results in much less alteration of crop composition than traditional breeding methods which are generally regarded as safe.” Herman R, and Price, D. J. Agr. Food Chem, 2013 -- also true for the European Food Safety Authority’s findings on substantial equivalence

“OK, but what if something else unknown has happened that’s bad “OK, but what if something else unknown has happened that’s bad?” - Absolute and relative safety To begin to answer this question would require extensive non-targeted analysis of the entire crop composition. And, this can be an unfocussed, open-ended and endless question. It is impossible to prove that any human activity has zero risk and this is true of GM food products also. There is no absolute safety. The international standard of GMO safety is “as safe as traditional foods”. USFDA’s general food safety standard is “a reasonable certainty of no harm”. Current GM foods seem to fully meet these relative safety standards.

CONCLUSIONS present no discoverable health risks, and we would expect There are very few risks inherent in producing GM crops and foods that are not also common in conventional plant breeding. So logically each example of a GM crop should be evaluated for safety based on its characteristics and not its method of production. Current GM crops and the foods produced from them present no discoverable health risks, and we would expect none. As far as science is able to tell, they are just as safe as conventional food. No well-substantiated examples of adverse health effects have been reported among millions of consumers (animal or human) over 20 years.

CONCLUSIONS Organisms producing pharmaceuticals or industrial chemicals need careful control and segregation from organisms intended for food use. This has been and is is likely to be challenging. Concurrent clearance for food use is important. Future GM organisms may involve more complex genetic changes and greater risks. Substantial equivalence may not exist e.g. with changes in the nutritional qualities of crops. Toxicological and regulatory approaches must continue to evolve to address this. This evolution is typical with most technologies.