Expert Report

Safety of Genetically Engineered Foods: Approaches to Assessing Unintended Health Effects (2004)


Genetic engineering is one of the newer technologies available to produce desirable traits in plants and animals used for food, but it poses no unique health risks that cannot also arise from conventional breeding and other genetic alteration methods. Any of those methods could result in unintended changes in the composition of the food. The report concludes that all altered foods should be assessed on a case-by-case basis before they are sold to the public to determine whether unintended changes in the composition of the food could adversely affect human health. Surveillance after a food is on the market might also be needed in some cases.

Key Messages

  • All new crop varieties, animal breeds, and microbial strains carry modified DNA that differs from parental strains. Methods to genetically modify plants, animals, and microbes are mechanistically diverse and include both natural and human-mediated activities.
  • Although current analytical methods can provide a detailed assessment of food composition, limitations exist in identifying specific differences in composition and interpreting their biological significance.
  • Analytical profiling techniques are appropriate for establishing compositional differences among genotypes, but they must also take into account modification of the profile obtained due to genotype-by-environmental interactions (the influence of the environment on expression of a particular genotype).
  • Current voluntary and mandated safety assessment approaches focus primarily on intended and predictable effects of novel components of GE foods. Introduction of novel components into food through genetic engineering can pose unique problems in the selection of suitable comparators for the analytical procedures that are crucial to the identification of unintended compositional changes.
  • Currently available bioinformatics and predictive tools are inadequate for correlating compositional analyses with biological effects.
  • During the past decade, analytical methodologies for separating and quantifying messenger ribonucleic acids, proteins, and metabolites have improved markedly. Applying these methodologies to the targeted analysis of known nutrients and toxicants will improve the knowledge base for these food constituents.
  • Health outcomes could be associated with the presence or absence of specific substances added or deleted using genetic modification techniques, including genetic engineering, and with unintended compositional changes.
  • Predictive tools to identify the expected behavior of complex and compound structures are limited and require a priori knowledge of their chemical structure, their biological relevance, and their potential interactive targets.
  • The knowledge base required to interpret results of profiling methods, however, is insufficiently developed to predict or directly assess potential health effects associated with unintended compositional changes of GM food, as is the necessary associative information (e.g., proteomics, metabolomics, and signaling networks).
  • The process of identifying unintended compositional changes in food is best served by combining premarket testing with postmarket surveillance, when compositional changes indicate that it is warranted, in a feedback loop that follows a new GM food or food product long term, from development through utilization.
  • There is a need, in the committee's judgment, for a broad research and technology development agenda to improve methods for predicting, identifying, and assessing unintended health effects from the genetic modification of food.