What is one key difference between RDA and AI?

RDA, or Recommended Dietary Allowance, is established based on comprehensive scientific research and extensive population studies. It aims to meet the nutrient needs of nearly all healthy individuals within a specific age and gender group. The goal of RDA is to provide a well-founded standard that reflects the intake levels associated with optimal health and prevention of nutrient deficiencies.

On the other hand, Adequate Intake (AI) is used in situations where there is not enough scientific evidence to calculate an RDA. AI is determined through expert judgment and is based on observational data, including intake levels that appear to promote health in a particular population. This may involve looking at average intakes of nutrients in healthy populations or estimating needs when research data are insufficient.

The distinction lies in the basis of their establishment: RDA is firmly rooted in extensive studies, while AI relies more on expert opinion and less robust data. This foundational difference highlights why the correct answer pertains to the nature of the methodologies used to derive these dietary guidelines.