Answer to Question 1
To help people meet dietary guidelines, the National Academy of Sciences has developed a set of dietary nutrient intakes for healthy people in the United States and Canada, the Dietary Reference Intakes (DRIs). The DRIs are based on a review of the most current research on adequate amounts and maximum safe nutrient intakes of healthy people. Within the umbrella of DRI are four types of reference values for planning and assessing diets:
1 . The Estimated Average Requirements (EAR) is the amount of nutrient that is estimated to meet the nutrient requirement of half the healthy people in specific age and gender groups. At this nutrient intake level, the nutritional requirements of the upper 50 percent of the people are not met.
2 . The Recommended Dietary Allowances (RDA) set forth the daily amount of a nutrient considered adequate to meet the known nutrient needs of nearly all healthy people in the United States. The RDA is set well above the EAR and covers about 98 percent of the population. The RDA could be considered a goal for adequate intake.
3 . When data are insufficient or inadequate to set an EAR, an Adequate Intakes (AI) value is determined instead of the RDA. The AI value is derived from approximations of observed nutrient intakes by a group or groups of healthy people. The AI value for children and adults is expected to meet or exceed the nutritional requirements of a specific healthy population.
4 . The Tolerable Upper Intake Levels (UL), which eventually will be available for all nutrients, establish the highest level of nutrient intake that seems to be safe for most healthy people and beyond which there is an increased risk of adverse effects. As intakes increase above the UL, so does the risk for adverse effects. Generally speaking, the optimum nutrient range for healthy eating is between the RDA and the UL.
Answer to Question 2
TRUE