The Dietary Reference Intakes (DRI) are a series of nutritional guidelines published by the Food and Nutrition Board of the Institute of Medicine. These guidelines are based on available science to evaluate the amounts of certain food compounds, such as vitamins and minerals, to support optimal health.
The DRIs are published, maintained, updated, and made freely available by the National Academies Press. They can be downloaded or viewed here.
These guidelines are discussed, amended, and updated periodically based on evolving science. The DRIs are developed with the goal of promoting “safety and adequacy” within the US food supply both in terms of promoting optimal health and avoiding disease.
Some compounds are missing adequate data to make conclusive recommendations. Others, such as Calcium or Magnesium have more robust data and the DRIs are able to set more specific guidelines.
Recommended Daily Allowance (RDA)
The RDA represents the recommended amount of a given nutrient required to meet the daily physiological needs of 97-98% of people. This level of recommendation requires the most robust availability of supportive data and isn’t available for all nutrients. The RDA is an advisory guideline based on the estimated adequate requirements of a compound.
Estimated Adequate Requirement (EAR)
The EAR describes the amount of a nutrient that will meet the daily needs of an estimated 50% of the US population. This level of the measure was designed to help develop nutritional strategies for large populations of people, not individuals. EARs are pre-requisites for the determination of an RDA. No EAR—no RDA.
Adequate Intake (AI)
When there is not enough available scientific data to generate and EAR and RDA, an estimate of required nutrition for healthy individuals to maintain an “adequate” nutritional state. Such adequacy is defined as maintaining regular growth rates, normal plasma levels of certain vitamins and minerals, and general well-being as determined from a clinical standpoint.
Tolerable Upper Intake Level (UL)
The UL is an estimate for the total amount of a certain nutrient that can be absorbed before negative side effects occur. This varies from nutrient to nutrient as well as life stage to life stage. Except in specific cases where a compound has specific life stage implications (such as folate in fetal brain development) the Tolerable Upper Intake Level isn’t used as a function nutritional guideline. That means maxing out a diet to the UL of every compound isn’t an advisable course of action. However, maxing out folate intake during pregnancy might be.
Dietary Reference Intakes for Magnesium
The EAR, RDA, and AI are often presented in varying availability for different life stages. Each reference type tends to vary from age to age, though often recommendations may remain somewhat consistent throughout life. Below is an example of the DRIs for magnesium. Note that the EAR and RDA are not available for infants in the 0-6 month and 7-12 month ranges. Therefore, an AI range is provided. For other stages, sufficient data exists to put forth an EAR and RDA—therefore there is no AI provided.
|0-6 m||30 mg||–||–|
|7-12 m||75 mg||–||–|
|1-3 y||–||65 mg||80 mg|
|4-8 y||–||110 mg||130 mg|
|9-13 y||–||200 mg||240 mg|
|14-18 y||–||340 mg||410 mg|
|19-30 y||–||330 mg||400 mg|
|31-50 y||–||350 mg||420 mg|
|51-70 y||–||350 mg||420 mg|
|> 70 y||–||350 mg||420 mg|
|9-13 y||–||200 mg||240 mg|
|14-18 y||–||300 mg||360 mg|
|19-30 y||–||255 mg||310 mg|
|31-50 y||–||265 mg||320 mg|
|51-70 y||–||265 mg||320 mg|
|> 70 y||–||265 mg||320 mg|
The Dietary Reference Intake publications maintained by the National Academies Press is an ideal place to learn more about the EAR, RDA, AI, and UL framework. Reports do well to describe the varying factors that go into consideration for each recommendation. Publications are available to view online (very well-formatted and organized), to download freely, or to purchase as physical copies.