FDA GRAS Dossier Preparation Guide: How to Conduct a Dietary Exposure Assessment and Key Considerations

General Principles of Dietary Exposure Assessment

• Comprehensiveness: The assessment must encompass all potential dietary sources, including natural occurrence, intended uses, other dietary sources (e.g., dietary supplements), and non-dietary sources (e.g., pharmaceutical uses).

• Representativeness: Estimates should be representative of the target population and account for the specific consumption patterns of different population subgroups, such as the general population, children, pregnant women, and high consumers.

• Conservativeness: In cases of data uncertainty or multiple plausible scenarios, conservative assumptions should be adopted to ensure that the assessment adequately captures the potential for the highest possible exposure levels.

• Transparency and Traceability: All data sources, calculation methods, assumptions, and any adjustment factors should be clearly documented to ensure the transparency and verifiability of the assessment process.

Key Data Sources and Methodologies

• Food Consumption Data: Assessments must rely on the most current and nationally representative food consumption survey data from authoritative sources. In the United States, the primary data source is the National Health and Nutrition Examination Survey (NHANES).

• Substance Concentration Data: This includes data on naturally occurring levels, added amounts during processing, and results from validated analytical methods used for quantification.

• Exposure Modeling Approaches: Common methodologies include point estimates (e.g., mean intake and high-percentile intake) and probabilistic models.

Common Considerations in Dossier Preparation

The dietary exposure assessment section of a GRAS notification typically includes the following key components: data sources and methodologies, estimated dietary exposure results, uncertainty analysis, and conclusions. Key considerations to be mindful of during drafting are outlined below:

• Integration with the Toxicological Section: The results of the dietary exposure assessment serve as a critical input to the toxicological safety evaluation. It is essential that exposure estimates are expressed in units consistent with those used in toxicological studies (e.g., mg/kg bw/day) to enable direct and meaningful comparisons between exposure levels and established toxicological benchmarks.

• Special Consideration for Sensitive Subpopulations: For substances intended for use in infant formula or foods for young children, particular attention must be paid to the intake estimates for these age groups. Due to their lower body weight and more limited dietary patterns, infants and young children may experience disproportionately higher exposure on a per-body-weight basis, warranting specific assessment.

• Avoiding Overly Conservative or Unrealistic Assumptions: While a conservative approach is generally appropriate in exposure assessment, excessively conservative or unrealistic assumptions may lead to unnecessarily inflated exposure estimates, resulting in wasted resources or the unnecessary rejection of a safe substance. Assumptions should be grounded in sound scientific evidence and reflect realistic use conditions.

• Clear Language and Professional Terminology: The exposure assessment section should be written in precise, technically accurate language, avoiding ambiguous or misleading expressions. The report should be logically structured and clearly presented to facilitate understanding by regulatory reviewers and other stakeholders.

• Continuous Updates and Data Validation: Dietary consumption patterns and food composition data evolve over time. Therefore, prior to submitting the GRAS dossier, it is critical to ensure that all referenced data are the most current, relevant, and representative of the intended use conditions and target population.