What is purpose of both the recommended dietary allowance and adequate intake?

The Recommended Dietary Allowance (RDA) serves as a guideline for the average daily intake level of essential nutrients that meets the needs of most healthy individuals in a specific age and gender group. Adequate Intake (AI), on the other hand, is used when there is insufficient evidence to establish an RDA; it represents a level of intake that is assumed to be adequate based on observed or experimentally determined estimates. Both aim to promote optimal health and prevent deficiencies in the population.