Final answer:
The RDA is designed to meet the needs of almost all (97.5%) healthy people. It is set based on the EAR to ensure that nutrient intakes are adequate to support health and well-being for various demographic groups, considering factors such as age, gender, and activity level.
Step-by-step explanation:
The Recommended Dietary Allowances (RDA) are guidelines designed to meet the nutritional needs of nearly all (97.5%) healthy individuals in a specific age and gender group. The RDA values act as a goal for daily intake to ensure adequate nutrition, taking into consideration various factors such as age, gender, health status, and activity level. By assessing the quality of people's diets against the RDA, nutritional professionals can guide individuals toward eating patterns that support overall health and well-being.
Importantly, the RDA is based on the Estimated Average Requirement (EAR), which is the average daily nutrient intake level estimated to meet the requirements of half the healthy individuals in a particular life stage and gender group. As a safeguard, the RDA is set higher than the EAR to cover the needs of most of the population. Factors influencing the exact nutrient needs include health conditions and lifestyle, such as physical activity level. Additionally, the Dietary Reference Intakes (DRIs) comprise a broader set of nutrient guidelines, including RDA, Adequate Intake (AI), Tolerable Upper Intake Level (UL), and EAR, catering to different needs and helping prevent chronic diseases.